thromboxane-b2 and Reperfusion-Injury

Cilostazol improves walking distance in peripheral arterial disease (PAD) patients. The study objectives were to assess the effects of cilostazol on walking distance, followed by the additional assessment of cilostazol on exercise-induced ischaemia-reperfusion injury in such patients.. PAD patients were prospectively recruited to a double-blinded, placebo-controlled trial. Patients were randomised to receive either cilostazol 100mg or placebo twice a day. The primary end-point was an improvement in walking distance. Secondary end-points included the assessment of oxygen-derived free-radical generation, antioxidant consumption and other markers of the inflammatory cascade. Initial and absolute claudication distances (ICDs and ACDs, respectively) were measured on a treadmill. Inflammatory response was assessed before and 30 min post-exercise by measuring lipid hydroperoxide, ascorbate, alpha-tocopherol, beta-carotene, P-selectin, intracellular and vascular cell-adhesion molecules (I-CAM and V-CAM), thromboxane B(2) (TXB(2)), interleukin-6, interleukin-10, high-sensitive C-reactive protein (hsCRP), albumin-creatinine ratio (ACR) and urinary levels of p75TNF receptor. All tests were performed at baseline and 6 and 24 weeks.. One hundred and six PAD patients (of whom 73 were males) were recruited and successfully randomised from December 2004 to January 2006. Patients who received cilostazol demonstrated a more significant improvement in the mean percentage change from baseline in ACD (77.2% vs. 26.6% at 6 weeks, p=0.026 and 161.7% vs. 79.0% at 24 weeks, p=0.048) as compared to the placebo. Cilostazol reduced lipid hydroperoxide levels compared to a placebo-related increase before and after exercise (6 weeks: pre-exercise: -11.8% vs. +5.8%, p=0.003 and post-exercise: -12.3% vs. +13.9%, p=0.007 and 24 weeks: pre-exercise -15.5% vs. +12.0%, p=0.025 and post-exercise: -9.2% vs. +1.9%, p=0.028). beta-Carotene levels were significantly increased in the cilostazol group, compared to placebo, before exercise at 6 and 24 weeks (6 weeks: 34.5% vs. -7.4%, p=0.028; 24 weeks: 34.3% vs. 17.7%, p=0.048). Cilostazol also significantly reduced P-selectin, I-CAM and V-CAM levels at 24 weeks as compared to baseline (p<0.05). There was no difference between treatment groups for ascorbate, alpha-tocopherol, interleukin-6 and -10, hsCRP and p75TNF receptor levels.. Cilostazol significantly improves ACD, in addition to attenuating exercise-induced ischaemia-reperfusion injury, in PAD patients.

Topics: Adult; Aged; Aged, 80 and over; Albuminuria; alpha-Tocopherol; Ascorbate Oxidase; beta Carotene; C-Reactive Protein; Cilostazol; Creatinine; Double-Blind Method; Female; Humans; Intercellular Adhesion Molecule-1; Interleukin-10; Interleukin-6; Intermittent Claudication; Lipid Peroxides; Male; Middle Aged; P-Selectin; Prospective Studies; Receptors, Tumor Necrosis Factor; Reperfusion Injury; Tetrazoles; Thromboxane B2; Vascular Cell Adhesion Molecule-1; Vasodilator Agents; Walking

Abdominal aortic aneurysmectomy (AAAectomy) results in a general ischemia-reperfusion syndrome accompanied by an acute rise in pulmonary artery pressure (PAP). We examined whether ulinastatin, a urinary trypsin inhibitor, prevents ischemia-reperfusion injury and increase in PAP after aortic unclamping (XU) during AAAectomy.. Prospective study.. Public, university-affiliated hospital.. Sixteen patients (11 males and 5 females) scheduled for AAAectomy.. The patients received 300000 IU of ulinastatin intravenously before XU (n = 8) or no additional treatment (n = 8) (control). Heart rate, central venous pressure, PAP, pulmonary arterial wedge pressure, arterial pressure, mixed venous oxygen saturation (Sv(O2)), and cardiac output were monitored. Arterial and mixed venous blood samples were analyzed for pH, Pa(CO2), Pa(O2), hemoglobin, and oxygen saturation, and the physiological shunt function (Qs/Qt) were calculated. Plasma concentrations of malondialdehyde, myeloperoxidase, granulocyte elastase, alpha1-antitrypsine, and thromboxane B2 and the stable hydrolysis products of thromboxane A2 were measured. Measurements were conducted before aortic crossclamping (XC) (baseline) and at 10, 30, and 60 minutes after XU.. A significant increase in PAP was observed 10 minutes after XU in the control group but not in the ulinastatin group. At 60 minutes after XU, Qs/Qt values had increased in the control group but had decreased in the ulinastatin group. There were no significant changes in malondialdehyde, thromboxane B2, granulocyte elastase, and alpha1-antitrypsine levels after XU in either group. A significant decrease in the plasma level of myeloperoxidase after XU was found in both groups.. The present study demonstrated that ulinastatin prevents increase in PAP and shunting after XU during AAAectomy.

Topics: Aged; alpha 1-Antitrypsin; Aorta; Aortic Aneurysm, Abdominal; Blood Pressure; Constriction; Female; Glycoproteins; Hemodynamics; Humans; Infusions, Intravenous; Intraoperative Period; Leukocyte Elastase; Male; Malondialdehyde; Peroxidase; Pulmonary Artery; Reperfusion Injury; Thromboxane B2; Trypsin Inhibitors

Eicosanoids, active metabolites of arachidonic acid (AA), play an important role in the regulation of renal haemodynamics and glomerular filtration. Our study verified the hypothesis on the positive action of exogenously administered PGE(1) on renal function during an operation with temporary ischaemia of the lower half of the body. Also the effect of alprostadil (prostaglandin E(1) analogue) administered during the operation of an abdominal aorta aneurysm on the postoperative systemic metabolism of AA and the glomerular filtration rate (GFR) was investigated. The study included 42 patients with a diagnosed abdominal aorta aneurysm who have been qualified for the operation of implantation of the aortic prosthesis. The patients were randomly assigned to two groups: the study group (I) receiving alprostadil and the control group (II) without alprostadil. The levels of hydroxyeicosatetraenoic acids (15-HETE, 12-HETE, 5-HETE) were determined by RP-HPLC and the level of thromboxane B(2) (TxB(2)) was determined by ELISA in the plasma of the blood drawn from vena cava superior immediately before aortic clamping (A) and 5 min after aortic declamping (B). The administration of PGE(1) affects the metabolism of 15-HETE in a manner dependent on the baseline value of GFR but does not significantly change the postoperative renal function. The metabolism of 15-HETE is affected by the baseline value of GFR1 and a longer period of ischaemia is correlated with lower concentrations of 5-HETE during reperfusion. The results of our studies indicate that TxB(2) influences the postoperative function of kidneys.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Aged; Alprostadil; Aortic Aneurysm; Eicosanoids; Female; Glomerular Filtration Rate; Humans; Hydroxyeicosatetraenoic Acids; Kidney; Male; Middle Aged; Postoperative Period; Reperfusion Injury; Thromboxane B2

Previous work has shown that cardiac ischemic preconditioning reduces cardiac reperfusion injury. We investigated whether cardiac ischemic preconditioning can improve lung preservation in patients who undergo valve replacement.. Forty patients with rheumatic heart disease requiring valve replacement were randomly divided into two groups. Twenty patients received two cycles of 3 minutes of aortic cross-clamping and 2 minutes of reperfusion before cardioplegic arrest (group IP), and 20 patients underwent 10 minutes of cardiopulmonary bypass (group C, control group). Blood samples from the pulmonary vein were collected to measure levels of polymorphonuclear leukocytes, superoxide dismutase, malonedialdehyde, and thromboxane B2, and arterial oxygen tension. Blood samples from the coronary sinus were used to measure calcitonin gene-related peptide values. Hemodynamic data were recorded by a pulmonary artery Swan-Ganz catheter. Lung tissue was collected after 1 hour of reperfusion to evaluate morphology. Clinical outcome data were recorded.. In group C (cardiopulmonary bypass and cardioplegic arrest), the levels of polymorphonuclear leukocytes, thromboxane B2, malonedialdehyde, and calcitonin gene-related peptide were increased after 1 hour of reperfusion, whereas the value for superoxide dismutase was decreased. In group IP, preconditioning attenuated the increase in polymorphonuclear leukocytes, thromboxane B2, and malonedialdehyde (p < 0.05) and increased superoxide dismutase and calcitonin gene-related peptide levels (p < 0.05). Preconditioning also increased arterial oxygen tension and cardiac index compared with controls (p < 0.05) and decreased mean pulmonary artery pressure and pulmonary vascular resistance index (p < 0.05). Histologic findings showed less lung injury and a lower polymorphonuclear leukocyte count in group IP than in group C (p < 0.05). Group IP had fewer postoperative pulmonary complications and a shorter intubation time.. Cardiac ischemic preconditioning improves lung preservation in patients having valve replacement. The mechanism may be that cardiac ischemic preconditioning reduces the accumulation of polymorphonuclear leukocytes in lung tissue and decreases the formation of oxygen free radicals.

Topics: Adult; Calcitonin Gene-Related Peptide; Cardiopulmonary Bypass; Female; Heart Arrest, Induced; Hemodynamics; Humans; Ischemic Preconditioning, Myocardial; Lung; Male; Malondialdehyde; Middle Aged; Neutrophils; Oxygen; Prospective Studies; Reperfusion Injury; Rheumatic Heart Disease; Superoxide Dismutase; Thromboxane B2

Steatosis accentuates the severity of hepatic ischaemia-reperfusion injury (IRI); 'statins' (HMG-CoA reductase inhibitors) protect the heart and brain against post-ischaemic injury. We tested whether short-term administration of atorvastatin protects fatty livers in obese mice against IRI.. Mice with dietary or genetic simple steatosis (SS) or non-alcoholic steatohepatitis (NASH) were subjected to 60 min partial hepatic ischaemia/24 h reperfusion. Atorvastatin was injected intravenously (5 mg/kg) 1 h before IRI. Liver injury, Toll-like receptor-4 (TLR4), cytokines/chemokines, iNOS/eNOS expression, eNOS activity and thromboxane B2 (TXB2) production were determined.. Ischaemia-reperfusion injury was exaggerated by two- to five-fold in SS and NASH compared with lean liver. Atorvastatin pretreatment conferred 70-90% hepatic protection in all animals. Atorvastatin increased post-ischaemic eNOS mRNA/protein and strikingly enhanced eNOS activity (by phospho-eNOS). It also attenuated microparticle (MP) production, NF-κB activation, significantly dampened post-ischaemic thromboxane B2 production, induction of TNF-α, IL-6, MIP-1a, MCP-1, GM-CSF and vascular cell adhesion molecule-1 (VCAM), with a resultant reduction on macrophage and polymorphonuclear neutrophil recruitment. Up-regulation of HMGB1 and TLR4 after IRI was marked in fatty livers; 1 h pretreatment with atorvastatin reduced HMGB1 and TLR4 expression in all livers.. Acute (1 h) atorvastatin administration is highly hepatoprotective against IRI in NASH, fatty and lean livers. Key mechanisms include suppression of inflammation by prevention of NF-κB activation, microvascular protection via eNOS activation and suppression of TXB2 and MP release. Short-term intravenous statin treatment is a readily available and effective preventive agent against hepatic IRI, irrespective of obesity and fatty liver disease, and merits clinical trials in at-risk patients.

Topics: Animals; Atorvastatin; Chemokines; Cytokines; HMGB1 Protein; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Liver; Male; Mice; Mice, Obese; NF-kappa B; Nitric Oxide Synthase Type III; Non-alcoholic Fatty Liver Disease; Reperfusion Injury; Thromboxane B2; Toll-Like Receptor 4; Vascular Cell Adhesion Molecule-1

This study is to investigate the effects of paeoniflorin on cerebral blood flow and the balance of PGI2/TXA2 of rats with focal cerebral ischemia-reperfusion injury. A total of 72 SD rats (3) were randomly divided into 6 groups: sham operation group, cerebral ischemia-reperfusion model group (I/R gourp), low (10 mg.kg-1), middle (20 mg.kg-1) and high (40 mg.kg-1) doses of paeoniflorin groups and nimrnodipine group. Focal cerebral ischemia in rats was made by inserting a monofilament suture into internal carotid artery for 90 min and then reperfused for 24 h. The effects of paeoniflorin on neurological deficit scores and the infarction volume of brain were detected. Relative regional cerebral blood flow (rCBF) was continuously monitored over ischemic hemispheres by laser-Doppler flowmetry (LDF). The expression of COX-2 in hippocampal CAl region was estimated by immunohistochemistry and the contents of prostacyclin I2 (PGI2), thromboxane A2 (TXA2), and ratio of PGIJ2/TXA2 in serum were measured by ELISA kits. Paeoniflorin significantly ameliorated neurological scores, reduced the infarction volume, and increased regional cerebral blood flow relative to the I/R group. In addition, paeoniflorin could inhibit COX-2 expression and the release of TXA2 and prevent the downregulation of PGI2 induced by I/R injury. The neuroprotective effects of paeoniflorin against focal cerebral ischemia-reperfusion rats might be attributed to improve the supply of injured hemisphere blood flow and adjust the balance between PGI2/TXA2.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Brain; CA1 Region, Hippocampal; Cyclooxygenase 2; Glucosides; Infarction, Middle Cerebral Artery; Male; Monoterpenes; Neuroprotective Agents; Paeonia; Plants, Medicinal; Random Allocation; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Reperfusion Injury; Thromboxane B2

Ischemia/reperfusion injury (IRI) is one of the major clinical problems in liver and transplant surgery. Livers subjected to warm ischemia in vivo often show a severe dysfunction and the release of numerous inflammatory cytokines and arachidonic acid metabolites. Cyclooxygenase (COX)-2 is the inducible isoform of an intracellular enzyme that converts arachidonic acid into prostaglandins. The aim of the study was to evaluate the effect of COX-2 inhibition and the role of Kupffer cells in IRI of the liver.. Male Wistar rats [250- 280 g body weight (BW)] were anesthetized and subjected to 30-min warm ischemia of the liver (Pringle's maneuver) and 60-min reperfusion after median laparotomy. The I/R group received no additional treatment. In the COX-2 inhibitor (COX-2I) group, the animals received 1 mg/kg BW meloxicam prior to operation. Gadolinium chloride (GdCl3) (10 mg/kg BW) was given 24 h prior to operation in the GdCl3 and GdCl3 + COX-2I groups for the selective depletion of Kupffer cells. The GdCl3 + COX-2I group received both GdCl3 and meloxicam treatment prior to operation. Blood and liver samples were obtained at the end of the experiments for further investigations.. After 30 min of warm ischemia in vivo, severe hepatocellular damage was observed in the I/R group. These impairments could be significantly prevented by the selective COX-2 inhibition and the depletion of Kupffer cells. Alanine aminotransferase was significantly reduced upon meloxicam and GdCl3 treatment compared to the I/R group: I/R, 3,240 ± 1,262 U/l versus COX-2I, 973 ± 649 U/l, p < 0.001; I/R versus GdCl3, 1,611 ± 600 U/l, p < 0.05, and I/R versus GdCl3 + COX-2I, 1,511 ± 575 U/l, p < 0.01. Plasma levels of tumor necrosis factor alpha (TNF-α) were significantly reduced in the COX-2I treatment group compared to I/R (3.5 ± 1.5 vs. 16.3 ± 11.7 pg/ml, respectively; p < 0.05). Similarly, the amount of TxB2, a marker for COX-2 metabolism, was significantly reduced in the meloxicam treatment groups compared to the I/R group: I/R, 22,500 ± 5,210 pg/ml versus COX-2I, 1,822 ± 938 pg/ml, p < 0.001, and I/R versus GdCl3 + COX-2I, 1,530 ± 907 pg/ml, p < 0.001. All values are given as mean ± SD (n = 6).. These results suggest that the inhibition of COX-2 suppressed the initiation of an inflammatory cascade by attenuating the release of TNF-α, which is an initiator of the inflammatory reaction in hepatic IRI. Therefore, we conclude that preferential inhibition of COX-2 is a possible therapeutic approach against warm IRI of the liver.

Topics: Animals; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Drug Evaluation, Preclinical; Gadolinium; In Situ Nick-End Labeling; Kidney Function Tests; Kupffer Cells; Liver; Liver Diseases; Male; Meloxicam; Rats, Wistar; Reperfusion Injury; Thiazines; Thiazoles; Thromboxane B2; Tumor Necrosis Factor-alpha

To evaluate the renoprotection effects of non-steroidal anti-inflammatory drugs (NSAIDs) in renal ischemia-reperfusion injury (IRI) and the cyclooxygenase (COX)-1/2 blockade association by indomethacin (IMT) in the mice model.. After the left renal pedicle of mice was clamped, IMT was administrated by intraperitoneal injection with four doses: 1, 3, 5, and 7 mg/kg. Blood and kidney samples were collected 24 h after IRI. The renal functions were assayed by the cytokines and serum creatinine (SCr) using enzyme-linked immunosorbent assay (ELISA) kits. Kidney samples were analyzed by hematoxylin and eosin (H&E) and immunohistochemistry stainings.. The mice administered with 5 mg/kg IMT had a marked reduction in SCr and significantly less tubular damage. The tumor necrosis factor α (TNF-α) activity in renal homogenates and interleukin 6 (IL-6) activity in serum had a marked reduction at doses of 5 and 7 mg/kg IMT. The administration of 3 and 5 mg/kg IMT had a marked reduction in the ratio of thromboxane B2 to 6-keto-prostaglandin F1α. COX-1 and COX-2 stainings were weaker in 5 mg/kg IMT groups than that in the other groups.. There was a dose response in the IMT function of renal IRI in mice, and IMT had a protective effect in a certain dose range. The effect of IMT on mice IRI was related to COX-1/2 blockades.

Topics: Acute Kidney Injury; Animals; Anti-Inflammatory Agents, Non-Steroidal; Creatinine; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Cytokines; Dinoprost; Disease Models, Animal; Immunohistochemistry; Indomethacin; Interleukin-6; Kidney; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Reperfusion Injury; Thromboxane B2; Tumor Necrosis Factor-alpha

The Wistar-Furth (WF) rat strain is usually used in models of full major histocompatibility complex-mismatched kidney transplantation. Because these rats have been demonstrated to be resistant to several models of chronic kidney disease, the aim of the present study was to investigate their potential resistance to renal ischaemia-reperfusion (I/R) injury compared with another strain, namely Wistar-Hanover (WH) rats. Anaesthetized male WH and WF rats were submitted to I/R by occlusion of the left renal artery and contralateral nephrectomy. Urine, blood and tissue samples were collected at different time points after I/R to evaluate renal function, inflammation and tubular injury, along with determination of nitric oxide synthase (NOS) expression and thromboxane A2 (TxA2 ) production. Post-ischaemic renal function was better preserved in WF than WH rats, as evidenced by reduced levels of creatininaemia, urinary neutrophil gelatinase-associated lipocalin excretion and proteinuria. In addition, WF rats had less intrarenal inflammation than WH rats after I/R injury. These observations were associated with maintenance of neuronal NOS expression, along with lower induction of inducible NOS expression in WF versus WH rats. Moreover, WF rats excreted a significantly lower amount of TxB2 . The results indicate that WF rats are more resistant to an I/R injury than WH rats in terms of renal function and inflammation. These observations are associated with differential regulation of intrarenal NOS expression, as well as a reduction in thromboxane production, which could contribute to a better outcome for the postischaemic kidney in WF rats.

Topics: Acute Disease; Animals; Dinoprostone; Disease Models, Animal; Kidney; Kidney Function Tests; Male; Nitric Oxide; Nitric Oxide Synthase; Oxidative Stress; Rats, Inbred WF; Real-Time Polymerase Chain Reaction; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; Thromboxane A2; Thromboxane B2

Steatosis accentuates the severity of hepatic ischemia-reperfusion injury (IRI). 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors ("statins") protect the heart and brain against post-ischemic injury, without necessarily lowering serum cholesterol. We tested whether 10-day or 1-day atorvastatin administration protects livers with fatty change or non-alcoholic steatohepatitis (NASH) against IRI.. Mice with dietary or genetic simple steatosis (SS) or NASH were subjected to 60 min of partial hepatic ischemia/24-h reperfusion, with/without atorvastatin administered with food (5 mg/kg body weight) for 10 days, or injected intravenously (5 mg/kg) 24 h before ischemia. Liver injury, Toll-like receptor-4 (TLR4), cytokines/chemokines, endothelial nitric oxide synthase (eNOS), activation and thromboxane B2 production were determined.. Atorvastatin conferred 70-90% hepatic protection against IRI in obese animals with SS or NASH, in which IRI was accentuated twofold to fivefold. IRI markedly upregulated TLR4 and activated nuclear factor-κB (NF-κB); atorvastatin abrogated these effects, as well as activating eNOS. Atorvastatin dampened the post-ischemic induction of thromboxane B2, macrophage inflammatory protein-1a, monocyte chemotactic protein-1, tumor necrosis factor-α, interleukin (IL)-12 p40, γ-interferon, IL-6, and adhesion molecules (vascular cell adhesion molecule-1, E-selectin, vascular endothelial-cadherin), and reduced macrophage and neutrophil recruitment. There was no reduction in serum cholesterol that could explain these effects, and hepatic cholesterol was normal in these mice. A single 24-h injection of atorvastatin conferred equivalent hepatoprotection.. Statins exert major hepatoprotection against IRI in lean, fatty, and NASH livers that is not due to cholesterol removal. Rather, statins downregulate TLR4 to prevent NF-κB activation, with resultant suppression of adhesion molecules, chemokines/cytokines, and thromboxane B2 production. Short-term statin treatment is an effective, readily-available preventive agent against hepatic IRI, irrespective of obesity and fatty liver disease.

Topics: Administration, Oral; Animals; Atorvastatin; Cell Adhesion Molecules; Cytokines; Cytoprotection; Disease Models, Animal; Down-Regulation; Drug Administration Schedule; Enzyme Activation; Fatty Liver; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Injections, Intravenous; Liver; Male; Mice; Mice, Obese; NF-kappa B; Nitric Oxide Synthase Type III; Non-alcoholic Fatty Liver Disease; Obesity; Pyrroles; Reperfusion Injury; RNA, Messenger; Thromboxane B2; Time Factors; Toll-Like Receptor 4

The present study attempts to evaluate the role of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling in intestinal ischemia/reperfusion (I/R)-induced intestinal injury and whether immediate ischemic postconditioning ameliorates intestinal injury via attenuation of intestinal mucosal apoptosis subsequent to inhibiting JAK/STAT signaling activation. Anesthetized adult male Sprague-Dawley rats were subjected to superior mesenteric artery occlusion consisting of 60 min of ischemia and 2 h of reperfusion; sham laparotomy served as controls. Animals received either subcutaneous administration of JAK2 inhibitor (AG490, 8 mg/kg) or STAT inhibitor (rapamycin, 0.4 mg/kg) 30 min before ischemia. Ischemic postconditioning was performed by three cycles of 30-s reperfusion and 30-s ischemia initiated immediately upon reperfusion. It was found that intestinal I/R resulted in conspicuous intestinal injury evidenced by significant increases in Chiu's score, lactic acid, and diamine oxidase activity, accompanied with increases in plasma levels of 15-F2t-isoprostane, endothelin 1, and thromboxane B2, as well as increase in the intestinal tissue myeloperoxidase activity. Meanwhile, the apoptotic index and cleaved caspase 3, phosphorylated JAK2, phosphorylated STAT1, and phosphorylated STAT3 expression were significantly enhanced versus sham control. Both ischemic postconditioning and pretreatment with AG490 or rapamycin significantly attenuated all the above changes. These results indicate that JAK/STAT pathway activation plays a critical role in I/R-induced intestinal injury, which is associated with increased oxidative stress, neutrophil accumulation, intestinal mucosal apoptosis, and microcirculation disturbance. Ischemic postconditioning mediates attenuation of intestinal I/R injury, and cell apoptosis may be attributable to the JAK/STAT signaling inhibition.

Topics: Amine Oxidase (Copper-Containing); Animals; Apoptosis; Caspase 3; Dinoprost; Endothelin-1; Enzyme Activation; Enzyme Inhibitors; Immunosuppressive Agents; Intestinal Mucosa; Ischemic Preconditioning; Janus Kinase 2; Lactic Acid; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; STAT3 Transcription Factor; Thromboxane B2; Tyrphostins

Ischemia-reperfusion (IR) can lead to serious tissue oxidative injury in animals. ShuJinHuoXue tablet (SJHXT) is a Chinese Traditional Medicine which can relax the muscles and stimulate the blood circulation and has been used as a clinical medicine. In the present study, we investigated the effects of SJHXT pretreatment on oxidative injury using an animal model of acute limb IR. Results showed that SJHXT pre-treatment (200, 300 and 400 mg/kg/day) markedly reduced serum endothelin-1 (ET-1), thromboxane B2 (TXB₂) levels and thromboxane B2/6-keto- prostaglandin F1α (TXB₂/6-Keto-PGF(1α)), wet weight/dried weight (W/D) ratio, myeloperoxidase (MPO), creatine kinase (CK), lactate dehydrogenase (LDH) activities, and increased serum nitric oxide (NO), 6-Keto-PGF(1α) levels and NO/ET-1 ratio in the IR+SJHXT groups. In addition, the SJHXT pre-treatment (200, 300 and 400 mg/kg/day) markedly reduced skeletal muscle Ca²⁺, malondialdehyde (MDA) levels, increased Na⁺-K⁺-ATPase, Ca²⁺-Mg²⁺-ATPase, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities. Our results suggest that SJHXT pre-treatment may improve skeletal muscle blood vessel microcirculation, decrease skeletal muscle oxidative injury and enhance antioxidant enzymes activities in IR animals.

Topics: Animals; Ca(2+) Mg(2+)-ATPase; Catalase; Creatine Kinase; Drugs, Chinese Herbal; Endothelin-1; L-Lactate Dehydrogenase; Malondialdehyde; Muscle, Skeletal; Nitric Oxide; Peroxidase; Phytotherapy; Prostaglandins F; Rabbits; Reperfusion Injury; Sodium-Potassium-Exchanging ATPase; Superoxide Dismutase; Tablets; Thromboxane B2

The present study aimed to investigate the protective effects of injectable caltrop fruit saponin preparation (ICFSP) on ischemia-reperfusion injury in rat brain. Rats were injected with ICFSP and then subjected to cerebral ischemia-reperfusion injury induced by middle cerebral artery occlusion. Then the neurological deficit score was evaluated by Bederson's method. The infarct size was assessed by TTC staining. The content of malondialdehyde (MDA) and nitric oxide (NO), and the activity of superoxide dismutase (SOD) in rat cerebrum were measured with kits, and the content of 6 K prostaglandin F1α (6-K-PGF 1α), thromboxane B2 (TXB2) and endothelin (ET) in blood plasma was measured by radioimmunoassay. The results demonstrated that ICFSP led to a decrease in infarct size (p < 0.01), neurological deficit score (p < 0.05) and plasma content of TXB2 and ET (p < 0.05), and an increase of the plasma level of 6-K-PGF 1α (p < 0.05) and SOD activity in cerebrum, where the MDA and NO content were decreased. The treatment improved forelimb function. ICFSP showed a similar potency compared to that of Ligustrazine hydrochloride parenteral solution (LHPS) and nimodipine (Nim). We concluded that ICFSP protects the brain damage caused by ischemia-reperfusion injury in rats, and this may be closely related to the regulation of reactive oxygen species (MDA and SOD activity) and NO levels in the rat cerebrum, as well as vasoactive factors in the plasma (6-K-PGF 1α, TXB2 and ET).

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents; Calcium Channel Blockers; Cerebral Infarction; Cerebrum; Endothelins; Forelimb; Fruit; Infarction, Middle Cerebral Artery; Injections; Male; Malondialdehyde; Neuroprotective Agents; Nitric Oxide; Phytotherapy; Plant Extracts; Rats; Rats, Wistar; Reperfusion Injury; Saponins; Superoxide Dismutase; Thromboxane B2; Tribulus

Prostanoids play a pivotal role among the inflammatory mediators associated with I/R injury. The aim of this study was to determine the effects of oral supplementation of n-3 polyunsaturated fatty acids (PUFA)-rich oil on inflammatory reactions and microcirculatory disorders caused by a hepatic warm I/R in rats. The rats were orally supplemented with n-3 PUFA-rich oil, n-6 PUFA-rich oil, or the same volume of water for 7 days. The PUFA concentration in the blood and liver tissues were evaluated, and the effects on I/R injury of the liver were assessed. The n-3 PUFA supplementation elevated the n-3/n-6 ratio in the blood and liver tissues. After reperfusion, thromboxane B(2) in the blood and prostaglandin E(2) in the liver were significantly suppressed in the n-3 PUFA-treated rats. Hepatic microcirculation was well maintained from the early phase (30 min) of reperfusion, and the serum concentrations of TNF-alpha and IL-6 were significantly lower in this group. The transaminase blood levels were also suppressed in the n-3 PUFA-treated rats. Expression of COX-2 mRNA was increased in all groups at 2 h after reperfusion but there were no differences among three groups. In conclusion, preoperative n-3/n-6 ratio augmentation in the blood and in the liver can result in a successful alleviation of hepatic I/R injury.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Interleukin-6; Liver; Male; Rats; Rats, Wistar; Reperfusion Injury; RNA, Messenger; Thromboxane B2; Tumor Necrosis Factor-alpha

Inflammatory responses exacerbate ischemia-reperfusion (IR) injury of spinal cord, although understanding of mediators is incomplete. The major inducible 70kDa heat shock protein (hsp70) is induced by ischemia and extracellular hsp70 (e-hsp70) can modulate inflammatory responses, but there is no published information regarding e-hsp70 levels in the cerebrospinal fluid (CSF) or serum as part of any neurological disease state save trauma. The present work addresses this deficiency by examining e-hsp70 in serum and CSF of dogs in an experimental model of spinal cord IR injury. IR injury of spinal cord caused hind limb paraplegia within 2-3 h that was correlated to lumbosacral poliomalacia with T cell infiltrates at 3 d post-ischemia. In this context, we showed a 5.2-fold elevation of e-hsp70 in CSF that was induced by ischemia and was sustained for the following 3 d observation interval. Plasma e-hsp70 levels were unaffected by IR injury, indicating e-hsp70 release from within the central nervous system. A putative source of this e-hsp70 was ependymal cells in the ischemic penumbra, based upon elevated i-hsp70 levels detected within these cells. Results warrant further investigation of e-hsp70's potential to modulate spinal cord IR injury.

Topics: Animals; Disease Models, Animal; Dogs; Gene Expression; Gene Expression Regulation; Granulocyte Colony-Stimulating Factor; HSP70 Heat-Shock Proteins; Interleukin-3; Lipid Peroxides; Motor Neurons; Recombinant Fusion Proteins; Recombinant Proteins; Reperfusion Injury; Spinal Cord; Spinal Cord Ischemia; Thromboxane B2; Time Factors

This study investigated whether oral simvastatin and manidipine interact in protecting the perfused rat heart from ischemia-reperfusion damage. Simvastatin (0.3 to 3 mg/kg) and manidipine (1 to 10 mg/kg) were given orally singly or together to normocholesterolemic rats once a day for seven consecutive days. At the end of treatment, systolic blood pressure and heart rate were measured in conscious rats, and the lipid profile and other biochemical markers, such as thromboxane B(2), nitrite/nitrates and 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha)) were determined in the plasma. Hearts were then isolated, perfused with Krebs-Henseleit, and subjected to low flow ischemia-reperfusion injury. Post-ischemic recovery of left ventricular function was measured as left ventricular developed pressure and left ventricular end-diastolic pressure. Creatine kinase, lactate dehydrogenase, tumor necrosis factor-alpha and 6-keto-PGF(1alpha) were measured in the heart effluents. In conscious animals, simvastatin alone increased plasma 6-keto-PGF(1alpha) release while manidipine alone reduced systolic blood pressure with a slight sympathetic reflex increase in heart rate, and increased plasma nitrite/nitrates. The combined treatment produced the same effects, but significantly more marked, and accompanied by a significant reduction of thromboxane B(2). Combined treatment was also significantly more effective than the single drugs in protecting the hearts from ischemia-reperfusion injury, with inhibition of creatine kinase, lactate dehydrogenase and tumor necrosis factor-alpha, and enhancement of 6-keto-PGF(1alpha) during reperfusion. These data show that simvastatin and manidipine interact positively in protecting the rat heart from ischemia-reperfusion injury, possibly through increased prostaglandin and nitric oxide formation by the vascular endothelial cells.

Topics: Animals; Blood Glucose; Blood Pressure; Calcium Channel Blockers; Cholesterol; Creatine Kinase; Dihydropyridines; Epoprostenol; Heart Rate; Hydroxymethylglutaryl-CoA Reductase Inhibitors; In Vitro Techniques; Kinetics; L-Lactate Dehydrogenase; Lipids; Male; Nitrobenzenes; Piperazines; Rats; Reperfusion Injury; Simvastatin; Thromboxane B2; Triglycerides; Tumor Necrosis Factor-alpha

Bradykinin mediates acute inflammation by increasing microvascular permeability, vasodilation, leukocyte migration and accumulation, and the production of arachidonic acid via phospholipase A2 activation. Arachidonic acid metabolites, or eicosanoids, are potent modulators of biological functions, particularly inflammation. Bradykinin exerts its inflammatory effects via the bradykinin B2 receptor. The aim of this study was to evaluate the effect of a bradykinin B2 receptor antagonist, FR173657 (FR), on intestinal ischemia-reperfusion (I/R) injury. Twenty-eight mongrel dogs were divided into four groups (n = 7 per group). Group I underwent I/R alone, Group II underwent I/R and received FR treatment, Group III was sham operated, and Group IV was sham operated and received FR treatment. The FR treatment consisted of FR continuously from 30 min prior to ischemia to 2 hr after reperfusion. In the I/R procedure, the superior mesenteric artery (SMA) and vein were clamped for 2 hr and then released to permit reperfusion for 12 hr. The intramucosal pH (pHi), SMA blood flow, and mucosal tissue blood flow were measured during the reperfusion period. The serum thromboxane B2 and 6-keto-prostaglandin F1alpha levels were determined, and tissue samples were examined histologically. Results showed that tissue blood flow, pHi, and SMA blood flow after reperfusion were maintained in Group II in comparison with Group I. Histopathological examination showed less severe mucosal damage after reperfusion in Group II than in Group I. The serum thromboxane B2 and 6-keto-prostagland in F1alpha levels were significantly lower in Group II than in Group I (P < 0.05). We conclude that FR treatment appears to have clear protective effects on small bowel I/R injury by inhibiting the release of eicosanoids.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Bradykinin B2 Receptor Antagonists; Dogs; Female; Hemodynamics; Hydrogen-Ion Concentration; Intestinal Mucosa; Intestine, Small; Male; Mesenteric Artery, Superior; Quinolines; Regional Blood Flow; Reperfusion Injury; Thromboxane B2

Platelet activation and subsequent aggregation play a key role in the pathogenesis of ischemic brain damage. Recent studies revealed that enhanced platelet activation is also observed after ischemia, suggesting that secondary thrombus formation might participate in the development of cerebral infarction. The binding of platelet glycoprotein GPIIb/IIIa (integrin alpha(IIb)beta3) to fibrinogen is the final common pathway in platelet aggregation. Therefore, GPIIb/IIIa antagonists might be useful in acute ischemic stroke as well as in the secondary prevention of ischemic stroke. In the present study, we evaluated the effect of three compounds, FK419 ((S)-2-acetylamino-3-[(R)-[1-[3-(piperidin-4-yl) propionyl] piperidin-3-ylcarbonyl] amino] propionic acid trihydrate), a novel nonpeptide GPIIb/IIIa antagonist, ozagrel, a selective thromboxane A(2) synthase inhibitor, and argatroban, a thrombin inhibitor, on middle cerebral artery (MCA) patency and ischemic brain damage using photochemically induced MCA thrombosis model in guinea pigs. FK419, ozagrel, or argatroban was administered 5 min after the termination of photoirradiation. FK419 dose-dependently improved MCA patency by decreasing the total occlusion time, time to continuous reperfusion, and the number of cyclic flow reductions, at doses that inhibited ADP-induced platelet aggregation ex vivo. In contrast, ozagrel only improved total occlusion time, and argatroban showed no improvement in MCA patency. FK419 also reduced ischemic brain damage in a dose-dependent fashion, whereas ozagrel and argatroban did not. Finally, FK419 ameliorated neurological deficits, whereas ozagrel and argatroban did not. These results indicate that FK419, a GPIIb/IIIa antagonist, ameliorates ischemic brain damage by improving MCA patency after occlusion and that FK419 is a promising candidate for the treatment of acute ischemic stroke.

Topics: Animals; Antithrombins; Arginine; Blood Coagulation; Blood Platelets; Brain Ischemia; Disease Models, Animal; Guinea Pigs; Infarction, Middle Cerebral Artery; Male; Methacrylates; Pipecolic Acids; Platelet Aggregation Inhibitors; Platelet Glycoprotein GPIIb-IIIa Complex; Reperfusion Injury; Sulfonamides; Thromboxane B2

This study explored the effect of chronic hypoxia on the elevation of pulmonary vascular resistance caused by ischemia-reperfusion (IR) in anesthetized rats. Experiments were separated into five parts. In Part 1, we examined the increase in left pulmonary vascular resistance (Rpl) after ischemia of the left lung and localized the major site for the increased resistance of the left pulmonary vasculature in both the normoxic and chronic hypoxia groups. Here, IR induced a significant increase in Rpl in the normoxic but not the chronic hypoxia group. This increased Rpl in the normoxic group was attributed to contraction of pulmonary arterial segments. Part 2 and Part 3 were focused on the changes in plasma nitrate/nitrite (NOx) and thromboxane B(2) (TxB(2)) levels. TxB(2) increased significantly in the normoxic group, whereas NOx increased significantly in the chronic hypoxia group, following ischemia. Indomethacin (Part 4) prevented IR-induced increase in Rpl in the normoxic group, whereas the IR-induced increase in Rpl appeared in the chronic hypoxia group after N(G)-nitro-L-arginine methyl ester treatment (Part 5). We conclude that IR elicited increases in the cyclooxygenase products such as TxB(2), which in turn caused an increase in Rpl. However, this increased Rpl was attenuated by elevated NOx in the chronic hypoxia group.

Topics: Animals; Hypoxia; Intubation, Intratracheal; Lung; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Organ Size; Pulmonary Circulation; Rats; Rats, Wistar; Reperfusion Injury; Thromboxane B2; Vascular Resistance

To test the hypothesis that the physicochemical properties of perfluorochemical liquid used in partial liquid ventilation can influence ventilatory requirements, pulmonary mechanics, microvascular permeability, and vasoactive mediator release in the abnormal lung.. Prospective, controlled animal study.. Research laboratory in a university setting. SUBJECTS Male Sprague-Dawley rats: sham and intestinal ischemia/reperfusion injury.. Treatment with perfluorochemical partial liquid ventilation (PLV: PP-5 or H-130) or conventional mechanical ventilation (CMV) over 60 mins of superior mesenteric artery occlusion and 60 mins of reperfusion.. Gas exchange, ventilatory requirements, and pulmonary mechanics were measured in vivo. Subsequently, pulmonary vascular resistance, microvascular permeability, and thromboxane were measured by using the isolated perfused lung preparation. PLV with PP-5 required significantly (p <.05) higher positive end-expiratory pressure resulting in increased mean airway pressures and pulmonary vascular resistance in both sham and intestinal ischemia/reperfusion injured animals compared with those treated with CMV or PLV H-130. PLV PP-5 also resulted in significantly (p <.05) lower respiratory compliance and greater microvascular permeability compared with sham animals. Following intestinal ischemia/reperfusion injury, PLV H-130 treated animals had significantly higher (p <.05) respiratory compliance than those treated with PLV PP-5 and a significantly lower (p <.05) intestinal ischemia/reperfusion-mediated increase in microvascular permeability than those treated with CMV or PLV PP-5. Thromboxane levels were significantly higher (p <.01) in injured animals treated with CMV or PLV PP-5 compared with comparably treated shams, were significantly lower (p <.01) in both PLV groups than CMV, and were further attenuated (p <.01) by PLV H-130 compared with PLV PP-5 animals.. We conclude that PLV with perfluorochemical liquids attenuates pulmonary sequelae resulting from remote organ injury and that the extent of lung protection depends on the physicochemical properties of the perfluorochemical liquids.

Topics: Animals; Capillary Permeability; Chemical Phenomena; Chemistry, Physical; Fluorocarbons; Intestines; Liquid Ventilation; Lung; Lung Compliance; Male; Positive-Pressure Respiration; Pulmonary Circulation; Pulmonary Gas Exchange; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Respiratory Mechanics; Thromboxane B2; Vascular Resistance

This study investigated the effects of a selective COX-2 inhibitor, FK3311, on warm ischemia-reperfusion (I/R) injury in the canine lung.. Sixteen adult mongrel dogs were used in this study. In the FK group (n = 8), FK (1 mg/kg) was administered intravenously 15 min before ischemia and 15 min before reperfusion. In the control group (n = 8), a vehicle was injected in the same manner. Warm ischemia was induced for 3 h by clamping the left pulmonary artery, veins, and bronchus. Five-minute clamping tests of the right pulmonary artery were performed before ischemia and 30 min after reperfusion. During the test, left pulmonary vascular resistance (L-PVR), cardiac output (CO), and arterial oxygen pressure (PaO(2)) were measured. The lung specimens were simultaneously harvested for wet-to-dry weight ratio (WDR) measurements, histopathological studies, and polymorphonuclear neutrophil (PMN) counts. Serum thromboxane (Tx) B(2) and 6-keto-prostaglandin (PG) F(1alpha) (stable metabolites of TxA(2) and PGI(2), respectively) were also measured 30 min after reperfusion.. L-PVR, CO, PaO(2), and WDR were significantly (P < 0.05) better in the FK group than in the control group. Histological tissue edema was mild, and PMN infiltration was significantly (P < 0.05) reduced in the FK group compared to the control group. The serum TxB(2) levels were significantly (P < 0.05) lower in the FK group than in the control group, while 6-keto-PGF(1alpha) levels were not significantly (P < 0.05) reduced. Two-day survival rate was significantly (P < 0.05) better in the FK group than in the control group.. FK has protective effects on pulmonary I/R injury stemming from marked inhibition of TxA(2).

Topics: 6-Ketoprostaglandin F1 alpha; Anilides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cardiac Output; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dogs; Epoprostenol; Hemodynamics; Ischemia; Isoenzymes; Lung; Neutrophils; Oxygen; Partial Pressure; Prostaglandin-Endoperoxide Synthases; Pulmonary Artery; Pulmonary Circulation; Pulmonary Veins; Reperfusion Injury; Thromboxane B2; Time Factors; Vascular Resistance

The rat tail ischaemia--reperfusion model of acute hyperalgesia described by Gelgor et al. (Pain 24 (1986) 251) has been investigated pharmacologically and electrophysiologically. Despite the advantages of this reusable animal model, biochemical changes associated with the behavioural response have not been determined. After injury+/-subcutaneous diclofenac pretreatment, we investigated the behavioural response (changes to thermally-induced tail flick latency) and measured diclofenac, prostaglandin E(2), 6-keto-prostaglandin F(1 alpha) and thromboxane B(2) concentrations in the tail, spinal cord and brain. Subcutaneous injection of 40 mg kg(-1) diclofenac sodium abolished the hyperalgesic response, suppressed the increased eicosanoid production in the tail, inhibited eicosanoid synthesis in the brain, but gave equivocal effects on eicosanoid concentrations in the spinal cord. Injection of 10 and 20 mg kg(-1) diclofenac reduced the duration of hyperalgesia but did not abolish the behavioural response. Diclofenac concentrations in all three tissues were similar, being approximately 5--10% of the corresponding plasma concentrations. We propose that both central and peripheral mechanisms are associated with the hyperalgesia and that the findings lend indirect support to a central action for non-steroidal anti-inflammatory drugs.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents, Non-Steroidal; Behavior, Animal; Brain Chemistry; Diclofenac; Dinoprostone; Dose-Response Relationship, Drug; Eicosanoids; Hyperalgesia; Injections, Subcutaneous; Male; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Reperfusion Injury; Tail; Thromboxane B2

Liver grafts from non-heart-beating donors inevitably suffer from warm ischemic injury. In these grafts, large quantities of inflammatory cytokines and arachidonic acid metabolites are induced, further aggravating injury. Cyclooxygenase (COX) is an intracellular enzyme that converts arachidonic acid into prostaglandin (PG)G2 and PGH2. COX has two isoforms: constitutive COX-1 and inducible COX-2. The aim of this study was to evaluate the effects of COX-2 inhibition by FK3311 (FK) on warm ischemic injury in a canine total hepatic vascular exclusion (THVE) model.. Sixteen mongrel adult dogs were studied. The portal triad of the hilum and the inferior vena cava above and below the liver was clamped for 1 hour. Splanchnic decompression was achieved by active splenofemorojugular bypass. The animals were divided into two groups. FK (1 mg/kg) was administered in the FK group (n = 8), and saline was administered in the control group (n = 8). Hepatic venous blood was collected to measure serum alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase (LDH), and hyaluronic acid levels. Serum thromboxane (Tx)B2 and 6-keto-PGF1alpha levels were also measured. Hepatic tissue blood flow was estimated simultaneously. Liver specimens were harvested for histologic study and polymorphonuclear neutrophils were counted.. Alanine aminotransferase, aspartate aminotransferase, and hyaluronic acid 2 and 6 hours after reperfusion and LDH 30 minutes and 2 and 6 hours after reperfusion were significantly (p < 0.05) lower in the FK group than in the control group. Hepatic tissue blood flow remained significantly (p < 0.05) higher in the FK group than in the control group 1, 2, and 6 hours after reperfusion. Histologic tissue damage was mild and polymorphonuclear neutrophil infiltration was significantly lower (p < 0.05) in the FK group than in the control group 1 and 6 hours after reperfusion. Thirty minutes after reperfusion, TxB2 was significantly reduced (p < 0.05) in the FK group, and 6-keto-PGF1alpha was not significantly lower.. FK protected against hepatic warm ischemia-reperfusion injury by marked inhibition of TxA2.

Topics: 6-Ketoprostaglandin F1 alpha; Alanine Transaminase; Analysis of Variance; Anilides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cyclooxygenase 2; Disease Models, Animal; Dogs; Enzyme Inhibitors; Hyaluronic Acid; Isoenzymes; L-Lactate Dehydrogenase; Leukocyte Count; Liver; Liver Circulation; Neutrophils; Prostaglandin-Endoperoxide Synthases; Random Allocation; Reperfusion Injury; Thromboxane B2

Membrane phospholipid breakdown, caused by ischemia and reperfusion (I/R) of the liver, releases free fatty acids including arachidonic acids and lysophospholipids, which serve as precursors of various inflammatory lipid derivatives. Phospholipase A2 (PLA2) is a key enzyme that initiates this reaction. In this study, we tested our hypothesis that a type II PLA2 inhibitor, LY329722, could attenuate hepatic I/R injury caused by a 2-hr total hepatic vascular exclusion (THVE) in dogs.. Eighteen beagle dogs, subjected to a 2-hr THVE, were divided into three groups. Group 1 (n=6) was untreated and served as a control group. LY329722 was administered to animals in group 2 (n=6) intravenously (0.2 mg x kg(-1) x hr(-1)) for 60 min before ischemia, and to animals in group 3 (n=6) for 60 min starting 15 min before reperfusion (0.2 mg x kg(-1) x hr(-1)). Animal survival, systemic and splanchnic hemodynamics, hepatic tissue blood flow, liver functions, energy metabolism, hepatic venous thromboxane B2 and endothelin-1 levels, phospholipid levels and tumor necrosis factor-a mRNA expression in liver tissue, and histopathologic findings were evaluated.. Two-week animal survival was 33% (two of six) in group 1, and 100% (six of six) in groups 2 and 3. LY329722 improved systemic and splanchnic hemodynamics, hepatic tissue blood flow, and energy metabolism, reduced liver enzyme, thromboxane B2, and endothelin-1 release, prevented hepatic phospholipid degradation and tumor necrosis factor-alpha mRNA expression, and lessened histopathologic damage and the number of neutrophil infiltrating into the liver tissue.. The present study demonstrated that a type II PLA2 inhibitor, LY329722, attenuated hepatic I/R injury caused by a 2-hr THVE model in dogs.

Topics: Acetates; Animals; Dinoprost; Dogs; Endothelin-1; Energy Metabolism; Enzyme Inhibitors; Female; Hemodynamics; Indoles; Ischemia; Liver; Liver Circulation; Liver Function Tests; Phospholipases A; Phospholipases A2; Regional Blood Flow; Reperfusion Injury; Splanchnic Circulation; Thromboxane B2; Time Factors; Transcription, Genetic; Tumor Necrosis Factor-alpha

Pringle's procedure is commonly used during liver surgery, and it sometimes causes liver failure. Metabolites of arachidonic acid, which are converted by cyclooxygenase (Cox), are involved in ischemia-reperfusion injury. This study evaluated the effects of FK 3311, which selectively inhibits Cox-2, on ischemia-reperfusion injury during liver resection in dogs.. The animals were divided into four groups and subjected to 60 min of warm ischemia by partial inflow occlusion. The FK-treated groups (FK0.2: 0.2 mg/kg, FK1: 1 mg/kg, FK3: 3mg/kg) received FK3311, and the control group received vehicle. Following reperfusion, the nonischemic lobes were resected and remnant liver function was evaluated.. Tissue blood flow and serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and lactate dehydrogenase were significantly better in the FK1 and FK3 groups, especially FK1, than in the control group. Thromboxane B(2) was significantly lower in the FK1 and FK3 groups than in the control group. The level of 6-keto-prostaglandin F(1alpha) was significantly lower in the FK3 group and relatively unchanged in the FK1 group. Histological damage was milder in the FK1 group. There were significantly fewer polymorphonuclear neutrophils in the FK1 group than in the control group.. FK3311 ameliorates the ischemia-reperfusion injury caused by Pringle's procedure during extensive liver resection. This agent may be clinically useful in extended liver surgery involving vascular isolation.

Topics: 6-Ketoprostaglandin F1 alpha; Alanine Transaminase; Anilides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspartate Aminotransferases; Cyclooxygenase 2; Dogs; Female; Injections, Intravenous; Isoenzymes; L-Lactate Dehydrogenase; Liver; Liver Circulation; Liver Failure; Male; Postoperative Complications; Prostaglandin-Endoperoxide Synthases; Reperfusion Injury; Thromboxane B2

In the process of ischemia-reperfusion, inflammatory cytokines and arachidonic acid metabolites are released and followed by tissue damage. FK3311 (FK) is a selective cyclooxygenase-2 inhibitor that inhibits conversion of arachidonic acid into thromboxane A2 or prostaglandin I2. We investigated the effects of FK in canine lung transplantation.. FK3311 was administered in the FK group, and vehicle was injected in the control group. The left lung was orthotopically transplanted after 12-hour preservation in Euro-Collins solution. After reperfusion, the right pulmonary artery and bronchus were ligated, and the animals were observed. Pulmonary gas exchange and hemodynamics were measured, histopathologic damages were investigated, and technetium-99m-labeled albumin scintigraphy was performed. The serum prostanoid levels were also measured.. In the FK group, pulmonary gas exchange and hemodynamics were significantly (p < 0.05) better, histologic damage and neutrophil infiltration was reduced, and technetium-99m-albumin accumulation was considerably suppressed. Also, thromboxane B2 was significantly (p < 0.05) lower, but 6-keto-prostaglandin F1alpha was not significantly reduced.. FK3311 generates protective effects on lung transplantation by a marked inhibition of thromboxane A2.

Topics: Anilides; Animals; Cyclooxygenase Inhibitors; Dogs; Hemodynamics; Lung; Lung Transplantation; Pulmonary Gas Exchange; Reperfusion Injury; Thromboxane A2; Thromboxane B2

To compare the effects of extract F of red-rooted Salvia (EFRRS) on mucosal lesions of gastric corpus and antrum induced by hemorrhagic shock and reperfusion in rats.. The rats were subject to hemorrhagic shock and followed by reperfusion, and were divided randomly into two groups. Group 1 received saline, and group 2 received EFRRS intravenously. The index of gastric mucosal lesions (IGML) was expressed as the percentage of lesional area in the corpus or antrum. The degree of gastric mucosal lesions (DGML) was catalogued grade 0,1,2 and 3. The concentrations of prostaglandins (PGs) were measured by radioimmunoassay. The concentration of MDA was measured according to the procedures of Asakawa. The activity of SOD was measured by the biochemical way. The growth rates or inhibitory rates of above-mentioned parameters were calculated.. As compared with IGML (%), grade 3 damage (%) and MDA content (nmol/g tissue) of gastric antrum which were respectively 7.96 +/- 0.59, 34.86 +/- 4.96 and 156.98 +/- 16.12, those of gastric corpus which were respectively 23.18 +/- 6.82, 58.44 +/- 9.07 and 230.56 +/- 19.37 increased markedly (P <0.01), whereas the grade 0 damage, grade 1 damage, the concentrations of PGE(2) and PGI(2)(pg/mg tissue), the ratio of PGI(2)/TXA(2) and the activity of SOD (U/g tissue) of corpus which were respectively 3.01 +/- 1.01, 8.35 +/- 1.95, 540.48 +/- 182.78, 714.38 +/- 123.74, 17.38 +/- 5.93 and 134.29 +/- 13.35 were markedly lower than those of antrum which were respectively 13.92 +/- 2.25, 26.78 +/- 6.06, 2218.56 +/- 433.12, 2531.76 +/- 492.35, 43.46 +/- 8.51 and 187.45 +/- 17.67 (P<0.01) after hemorrhagic shock and reperfusion. After intravenous EFRRS, the growth rates (%) of grade 0 damage, grade 1 damage, the concentrations of PGE(2) and PGI(2), the ratio of PGI(2)/TXA(2) and the activity of SOD of corpus which were respectively 632.56, 308.62, 40.75, 74.75, 92.29 and 122.25 were higher than those in antrum which were respectively 104.89, 58.40, 11.12, 56.58, 30.65 and 82.64, whereas the inhibitory rates (%) of IGML, grade 3 damage and MDA content of gastric corpus were 82.93, 65.32 and 59.09, being higher than those of gastric antrum which were 76.64, 53.18 and 42.37.. After hemorrhagic shock reperfusion, the gastric mucosal lesions in the corpus were more severe than those in the antrum, which were related not only to the different distribution of endogenous PGs in the mucosa, but also to the different ability of anti-oxidation of the mucosa. The protective effect of EFRRS on the gastric mucosa in the corpus was more evident than that in the antrum, which was related to higher growth degree of PGs contents and anti-oxitative ability in gastric corpus after administration of EFRRS.

Topics: Alprostadil; Animals; Dinoprostone; Gastric Mucosa; Hydroxyl Radical; Male; Malondialdehyde; Phytotherapy; Plant Extracts; Pyloric Antrum; Rats; Rats, Wistar; Reperfusion Injury; Salvia; Shock, Hemorrhagic; Superoxide Dismutase; Thromboxane B2

Microvascular thrombosis plays a significant role in the pathophysiology of ischaemic reperfusion injury. A fish oil-supplemented diet containing n-3 polyunsaturated fatty acids (PUFA) reduces thromboxane A(2) (TxA(2)) synthesis and, thus, vasoconstriction and platelet aggregation. The aim of this study was to elucidate whether n-3 PUFA in a porcine model of ischaemia and reperfusion injury 1) inhibit accumulation of platelets and fibrinogen in ischaemia-reperfusion injured tissue, 2) prolong the bleeding time, and 3) inhibit TxA(2) synthesis. Nine pigs were fed a standard diet supplemented with 7 g n-3 PUFA/day for 3 weeks. Nine pigs on the standard diet served as controls. Unilateral myocutaneous flaps were exposed to ischaemia for a period of 6 hours. Contralateral flaps were nonischaemic. Tissue contents of radioactive-labelled platelets and fibrinogen were measured after 4 hours of reperfusion. Platelet count, serum TxB(2), and the cutaneous bleeding time were measured before and after 3 weeks of diet. In the fish oil group, the accumulation of platelets was significantly reduced in all the myocutaneous flaps, except in the ischaemic skin part, when compared to control animals. Fibrinogen was significantly reduced in nonischaemic flaps, but not in ischaemic flaps. After the feeding period, the level of TxB(2) was significantly lowered in the fish oil group (p<0.01). No difference in the bleeding time was observed. Thus, dietary supplementation with n-3 PUFA inhibits the formation of microvasculatory thrombosis in this model.

Topics: Animals; Bleeding Time; Dietary Fats, Unsaturated; Disease Models, Animal; Fatty Acids, Omega-3; Fibrinogen; Fish Oils; Microcirculation; Platelet Count; Reperfusion Injury; Swine; Thrombosis; Thromboxane B2

Topics: Anilides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cardiac Output; Dogs; Hemodynamics; Ischemia; Lung; Models, Animal; Oxygen; Partial Pressure; Pulmonary Artery; Pulmonary Circulation; Pulmonary Veins; Reference Values; Reperfusion Injury; Thromboxane B2; Vascular Resistance

The purpose of this study was to evaluate the effect of prostaglandin E1 (PGE1) on protecting against hepatic endothelial cell damage and increasing graft viability after cold preservation and reperfusion, using an isolated perfused rat liver (IPRL) model. The grafts were divided into three groups, according to the cold preservation time and PGE1 administration, namely: 4h preservation (group 1, n = 9), 6h preservation (group 2, n = 9), and 6h preservation followed by PGE1 infusion (group 3, n = 9). After cold storage, the grafts were put on the recirculating IPRL system, then reperfused for 120 min at 37 degrees C with oxygenated Krebs-Henseleit buffer containing hyaluronic acid (HA). To examine the function of the sinusoidal endothelial cells and hepatocytes, serial measurements of HA, tumor necrosis factor-alpha (TNFalpha), thromboxane B2 (TXB2), acid phosphatase, and conventional parameters in the perfusate were made. After perfusion, the trypan blue exclusion test was performed to assess the presence of any microscopic sinusoidal lining cell damage. In group 3, the bile output and HA clearance were significantly greater, while glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, TNFalpha, TXB2, and acid phosphatase in the perfusate were significantly lower than in group 2. Histologically, less endothelial cell damage and hepatocyte damage than in group 2 was also confirmed. These results therefore suggest that the improvement of hepatic graft viability by PGE1 administration is mainly due to sinusoidal endothelial cell protection.

Topics: Acid Phosphatase; Alanine Transaminase; Alprostadil; Animals; Aspartate Aminotransferases; Cryopreservation; Endothelium; Graft Survival; Hyaluronic Acid; L-Lactate Dehydrogenase; Liver Transplantation; Male; Rats; Rats, Inbred Lew; Reperfusion Injury; Thromboxane B2; Tumor Necrosis Factor-alpha

To explore the main pathogenic factors in the development of neuronal death during normothermic reperfusion in rabbits.. Ninety-six New Zealand rabbits were randomly allocated into two groups: group I served as non-ischemic controls; group II served as postischemic normothermic reperfusion models. Complete cerebral ischemia was induced by the four-vessel model for 30 minutes. After ischemia, rabbits in group II were further divided into three subgroups according to the duration of reperfusion: subgroup A, 30 minutes; subgroup B, 180 minutes and subgroup C, 360 minutes. Twenty-eight biochemical parameters in the brain were measured, and neuronal changes were observed by histomorphological assessment. Neurons of 12 regions were differentiated into four types: type A (normal), type B (mildly damaged), type C (severely damaged) and type D (necrotic). Bivariate correlate analysis between the levels of biochemical parameters and the percentages of each type of neurons was carried out.. The main parameters involved in the progressive decrement of type A neurons were VIP, beta-EP, PGI2, T3, T4 and Na+, K(+)-ATPase; in the increment of type B were beta-EP and TXB2; in the increment of type C were GLU and TXB2/PGI2 respectively; in the stepwise increment of percentages of type D neurons were T4, Na+, K(+)-ATPase, GLU, T3 and VIP (P < 0.05).. The main factors involved in the development of neuronal death during postischemic normothermic reperfusion in rabbits include hypermetabolism, deactivation of Na+, K(+)-ATPase, release of excitatory amino acids and disorder of neuropeptides.

Topics: Animals; beta-Endorphin; Brain Ischemia; Cell Death; Female; Male; Neurons; Rabbits; Random Allocation; Reperfusion Injury; Sodium-Potassium-Exchanging ATPase; Thromboxane B2; Vasoactive Intestinal Peptide

Intestinal reperfusion (IR)-induced pulmonary edema has been related to endogenous pulmonary thromboxane A2 (TxA2) release. This study examines the hypothesis that alveolar macrophages (aMphis) activated during IR are an important cellular source of TxA2 in this model. Anesthetized Sprague Dawley rats underwent 120 min of intestinal ischemia and 60 min of reperfusion (IR) or sham operation (Sham). aMphis were isolated by bronchoalveolar lavage and incubated in Krebs buffer for 30 min, after which the supernatant was analyzed for TxB2 (metabolite of TxA2) and prostaglandin E2. Other parameters of aMphi activation measured included lysosomal enzyme release (beta-glucuronidase), superoxide (O2-) release, and procoagulant activity. aMphis from animals sustaining IR generated more than twice as much TxA2 and prostaglandin E2 as did those isolated from controls (p < .05). Other evidence of aMphi activation included a nearly 100-fold increase in procoagulant activity, a 7-fold increase in beta-glucuronidase release, and a 2.5-fold increase in O2- release over that of controls (p < .05). These data suggest that TxA2 is a major eicosanoid product of aMphis during IR and that aMphis may be an important cellular participant in IR-induced pulmonary microvascular injury, either directly by releasing O2-, lysosomal enzymes, and pro-coagulant factors, or indirectly by generating TxA2.

Topics: Animals; Blood Coagulation; Cells, Cultured; Dinoprostone; Glucuronidase; Intestines; Ischemia; Lysosomes; Macrophage Activation; Macrophages, Alveolar; Male; Mesenteric Arteries; Pulmonary Edema; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Superoxides; Thromboxane B2

The lung injury regularly associated with cardiopulmonary bypass (CPB) may be linked to gut mucosal dysfunction occurring as the result of mucosal ischemia associated with nonpulsatile CPB. To examine this possibility we postulated that the weak-beta 2 agonist dopexamine would improve gut mucosal blood flow, thereby decreasing gut and lung dysfunction seen after CPB in sheep.. Anesthetized sheep had 2 h of hypothermic (24 degrees C), nonpulsatile CPB, and 60 min of cold, blood cardioplegic arrest. After warming they were separated from CPB for 2 h of reperfusion. Before and during CPB, dopexamine at 2 micrograms/kg/min (n = 7) or saline (n = 7) were infused in a blinded fashion. Hemodynamic parameters were measured. Biatrial thromboxane B2 levels were obtained. Mesenteric arterial flow (QSMA), mucosal flow (Qmuc), FD-4 clearance (ClFD-4), and tonometric pHi were measured at baseline and 30-min intervals on, and after, CPB.. After CPB, similar reductions in MAP were seen (P < 0.05 vs. baseline), but heart rate and the mean pulmonary vascular resistance were significantly increased in the dopexamine animals (P < 0.05 vs. placebo). Plasma thromboxane was similarly increased in both groups after CPB (P < 0.05 vs. baseline), returning to baseline 1 h after CPB. The Qsma was not altered, but a statistically significant decrease in Qmuc and pHi occurred in both groups (P < 0.05 vs. baseline). In both groups FD-4 clearance reached a peak 30 min after CPB (P < 0.05; dopexamine vs. baseline). After 2 h neither of these changes returned to control levels.. In this ovine model, gut mucosal ischemia and increased permeability occur with hypothermic CPB, but dopexamine administration during CPB, compared to placebo, neither ameliorates these intestinal derangements nor reduces post-CPB lung pathophysiology.

Topics: Adrenergic beta-Agonists; Animals; Capillary Permeability; Cardiopulmonary Bypass; Dopamine; Hemodynamics; Hydrogen-Ion Concentration; Intestinal Mucosa; Lung; Mesenteric Arteries; Oxygen; Pulmonary Circulation; Reperfusion Injury; Sheep; Thromboxane B2

RGD-containing peptides and other antagonists of the platelet glycoprotein (GP) IIb/IIIa may induce a high-affinity binding site for fibrinogen and the expression of novel epitopes, called ligand-induced binding sites (LIBS). The functional relevance of LIBS expression in a canine model of coronary thrombolysis induced by tissue-type plasminogen activator (t-PA) was examined. Ro43-5054 (N-[N-[N-(p-amidinobenzoyl)-b-alanyl]-l-a-aspartyl]-3-phenyl-l- alanine) and Ro44-9883 ([1-(N-(p-amidinobenzoyl)-l-tyrosyl)-4-piperidinyl)oxy]acetic acid), antagonists of the GP IIb/IIIa receptor, were administered in increasing doses of 2 to 10 microg/kg/min, beginning 30 min before the infusion of t-PA. LIBS expression was determined by the binding of the monoclonal antibody, D3GP3, to platelets on exposure to Ro43-5054, Ro44-9883 and t-PA. Ro43-5054 was shown to induce LIBS, whereas Ro44-9883 and t-PA did not. Both drugs abolished platelet aggregation in response to U46619 and ADP ex vivo. Reocclusion was prevented with both Ro43-5054 and Ro44-9883, but neither drug altered reperfusion times (49 +/- 8 and 55 +/- 39 min). Both drugs increased the rate of bleeding compared with t-PA alone, but there was no difference in hemostasis between the two drugs. To determine whether the drugs differed in their effect on platelet activation in vivo, urinary 2,3-dinor-thromboxane (TX) B2, a major metabolite of TXB2, was determined by gas chromatography-mass spectrometry. After reperfusion, the urinary 2,3-dinor-TXB2 increased in the Ro43-5054-treated group, similar to control groups (32 +/- 8 and 37 +/- 9 ng/mg creatinine). This increase was blunted in the Ro44-9883-treated group (9 +/- 3 ng/mg creatinine). GP IIb/IIIa antagonists that do not induce LIBS result in a greater suppression of platelet activity but not in any discernible functional benefit in vivo.

Topics: Acetates; Animals; Binding Sites; Blood Platelets; Coronary Thrombosis; Dogs; Fibrinolytic Agents; Hemorrhage; Oligopeptides; Platelet Aggregation; Platelet Aggregation Inhibitors; Platelet Glycoprotein GPIIb-IIIa Complex; Reperfusion Injury; Thromboxane B2; Tissue Plasminogen Activator; Tyrosine

Renal function can be severely impaired through injuries sustained after both short and prolonged periods of complete ischemia. The magnitude of renal dysfunction resulting from these conditions and their reversibility depend on the duration of anoxia. In this study, we used a Sprague-Dawley rat model (5 to 7 rats in each group) to study the pathogenesis of short-term ischemia (30, 60, and 120 min)/reperfusion (2, 4, 24 h, 1 wk, and 3 wk) injury of the kidney under warm (room temperature) or cold (4 degrees C) conditions. Ischemia was induced by clamping the renal artery. Changes in kidney weight, histopathology, concentrations of serum thromboxane and leukotriene, and tissue malonyldialdehyde (MDA) concentration, numbers of apoptotic bodies, and p53 expression in the kidney were compared with those of sham-operated rats. The results showed that the immediate increase in kidney weight due to inflammatory swelling was associated with simultaneous elevation of serum thromboxane and leukotriene levels. The changes in mediator levels were closely related to the duration of ischemia and temperature. Histologic structures were preserved better when renal artery clamping was done at 4 degrees C. MDA peroxidation products from the ischemic tissue prominently increased 1 week following ischemia; this paralleled a secondary increase in leukotriene levels. Flow cytometric detection of p53 oncoprotein showed a marked increase at 1 week following ischemia, which was accompanied by the development of apoptotic bodies in ischemic tissues. These changes were also closely related to the ischemic time and temperature during ischemia. This animal model may be useful for future studies of the prevention of ischemia/reperfusion injury of the kidney and for selection of effective antioxidants.

Topics: Animals; Apoptosis; Kidney; Leukotriene B4; Lipid Peroxidation; Organ Size; Rats; Rats, Sprague-Dawley; Renal Artery Obstruction; Reperfusion Injury; Thromboxane B2

We investigated the effects of low-dose Beraprost sodium (BPS), a stable prostaglandin I2 (PGI2) analogue, on microvascular permeability and the plasma concentrations of thromboxane and adenosine 3',5'-cyclic monophosphate (cAMP) in blood-perfused rabbit lungs subjected to ischemia-reperfusion (I/R). After an ischemic insult for 2 h, saline as a vehicle, 3 pmol/L of BPS (BPS-1), 150 to 300 pmol/L of BPS (BPS-2), 900 pmol/L of BPS (BPS-3), or 60 micromol/L of indomethacin (IND) was administered into the reservoir, then the lungs were reperfused and reventilated for 1 h. Vascular permeability was assessed by determining the microvascular filtration coefficient (Kf, ml/min/mm Hg/100 g wet lung). I/R resulted in increases in vascular resistance, Kf, and thromboxane. BPS-2, BPS-3, and IND inhibited the increase in vascular resistance, and BPS-3 and IND attenuated the increases in Kf and thromboxane. BPS-3 increased, but IND decreased, the concentrations of cAMP in the perfusate. Perfusate thromboxane released after reperfusion was significantly correlated with Kf. We conclude that cyclooxygenase products play a critical role in I/R-induced lung vascular injury and that 900 pmol/L of BPS inhibits the production of thromboxane and enhances the permeability barrier via a cAMP-elevating effect. However, vasodilatory action of BPS may exacerbate the reperfused lung injury by increasing the flow through injured capillaries via inhibition of thromboxane-induced vasoconstriction.

Topics: 6-Ketoprostaglandin F1 alpha; Analysis of Variance; Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Blood Pressure; Capillaries; Capillary Permeability; Cyclic AMP; Epoprostenol; Indomethacin; Lung; Lung Diseases; Male; Microcirculation; Rabbits; Reperfusion Injury; Respiration, Artificial; Thromboxane B2; Tumor Necrosis Factor-alpha; Vascular Resistance; Vasodilation; Vasodilator Agents

Multiple drugs have been used in experimental skin flap models to reduce the effects of reperfusion ischemia. The effects of antiproteases, however, have not been studied. A skin flap ischemia reperfusion model was developed in the rat to study the effects that aprotinin, a broad-spectrum antiserine protease, would have on skin flap viability. Thirty-two male rats underwent elevation of a ventral pedicled skin flap based on the superficial inferior epigastric artery. The flaps were subjected to 10 hr of warm ischemia by clamping the neurovascular pedicle followed by reperfusion. Aprotinin or saline (control) was administered systemically via the contralateral femoral vein either before or after the ischemic insult. Full-thickness skin biopsies were obtained at 1, 8, and 24 hr into reperfusion. Biopsies were evaluated for neutrophil concentration (using a myeloperoxidase [MPO] assay) and thromboxane B2 [TxB2] content. Flap survival was calculated at 1 week using standardized photography and computer-assisted digital imaging. Aprotinin given before an ischemic insult significantly improved flap survival compared to saline controls (52.3% alive vs. 29.6%, P = 0.0132, unpaired t-test). Aprotinin given after ischemia did not significantly influence flap survival (28.8% vs. 34.4% in saline controls, P = 0.708). MPO levels in the aprotinin preischemia treatment group were significantly less at 1 and 8 hr into reperfusion, indicating decreased neutrophil numbers. No statistical difference in TxB2 levels was noted in either group at any time after reperfusion. Aprotinin significantly improves skin flap survival when given prior to but not after an ischemic insult. Aprotinin appears to lower the concentration of neutrophils in skin flaps pretreated with the drug. Reperfused skin flap levels of thromboxane B2 are unaffected by the pre- or postischemic administration of aprotinin.

Topics: Analysis of Variance; Animals; Aprotinin; Disease Models, Animal; Drug Evaluation, Preclinical; Male; Neutrophils; Peroxidase; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Serine Proteinase Inhibitors; Skin; Surgical Flaps; Thromboxane B2; Time Factors; Tissue Survival

These serial clinical and experimental studies were designed to clarify the pathogenesis of postburn MODS. Both animal and clinical studies were performed. In animal experiments, 46 male cross-bred dogs were cannulated with Swan-Ganz catheters and 39 of them were inflicted with 50% TBSA third degree burns (7 were used as controls). The burned dogs were randomly divided into 4 groups: immediate infusion, delayed infusion, delayed fast infusion and delayed fast infusion combined with ginsenosides. All dogs were kept under constant barbiturate sedation during the whole study period. Hemodynamics, visceral MDA, mitochondrial respiratory control rate (RCR) and ADP/O ratio, ATP, succinic dehydrogenase (SDH), organ water content as well as light and electron microscopy of visceral tissues were determined. In the clinical study, 61 patients with extensive deep burns were chosen, of which 16 sustained MODS. Plasma TXB2/6-keto-PGF1alpha ratio, TNF, SOD, MDA, circulatory platelet aggregate ratio (CPAR), PGE2, interleukin-1, total organ water content and pathological observations of visceral tissues from patients who died of MODS were carried out. Results demonstrated that ischemic-reperfusion damage due to severe shock, sepsis and inhalation injury are three main causes of postburn death. All inflammatory mediators increased markedly in both animals and patients who sustained organ damage or MODS. SDH, RCR, ADP/O and ATP decreased significantly. These findings suggested that ischemic damage and systemic inflammatory response syndrome (SIRS) initiated by mediators or cytokines might be important in the pathogenesis of postburn MODS.

Topics: 6-Ketoprostaglandin F1 alpha; Adenosine Diphosphate; Adenosine Triphosphate; Adult; Animals; Body Water; Burns; Central Nervous System Agents; Dinoprostone; Dogs; Female; Fluid Therapy; Ginsenosides; Hemodynamics; Humans; Hypnotics and Sedatives; Interleukin-1; Male; Malondialdehyde; Mitochondria; Multiple Organ Failure; Oxygen Consumption; Panax; Plants, Medicinal; Platelet Aggregation; Random Allocation; Reperfusion Injury; Saponins; Sepsis; Shock; Succinate Dehydrogenase; Superoxide Dismutase; Syndrome; Systemic Inflammatory Response Syndrome; Thromboxane B2; Tumor Necrosis Factor-alpha

To test the hypothesis that ischemia and reperfusion injury may contribute to the cause or nonhealing of venous ulcers, the effects of postural change on the microcirculation of ulcers and on levels of known mediators of reperfusion injury in their venous effluent were studied.. A standard protocol of stabilization (20 minutes), limb dependency (1 hour), and reelevation (2 hours) was used in 10 patients with venous leg ulcers as proven by clinical history, examination, ankle-brachial pressure index, and light reflective rheography. Superficial blood flow in and around ulcers was repeatedly examined with a new laser-Doppler scanning technique. Blood samples from the saphenous vein or a tributary adjacent to the ulcer before dependency and at 0, 10, 30, 60, and 120 minutes after reelevation were analyzed for tumor necrosis factor-alpha, interleukin (IL)-1RA, IL-1 beta, IL-6, platelet-activating factor, thromboxane B2, leukotriene B4, and P-selectin.. Scans showed a consistent pattern of high ulcer blood flow, which decreased on dependency (p < 0.05) and then returned to baseline levels on reelevation and (in 7 of 10) eventually exceeded initial values. Mediator assays showed that levels of platelet-activating factor, IL-1RA, and IL-6 were significantly higher in resting ulcer venous effluent than in systemic venous samples; the reverse was true for P-selectin. There was no statistically significant change in effluent concentration of any mediator as a function of posture, ulcer size, or healing.. Postural vasoregulation causes relative ischemia and reperfusion in venous leg ulcers. However, this is not associated with changes in release of mediators known to be related to reperfusion injury in internal organs.

Topics: Aged; Aged, 80 and over; Blood Pressure; Cytokines; Humans; Interleukin-1; Interleukin-6; Ischemia; Laser-Doppler Flowmetry; Leg; Leukotriene B4; Microcirculation; Middle Aged; P-Selectin; Platelet Activating Factor; Plethysmography, Impedance; Posture; Receptors, Interleukin-1; Regional Blood Flow; Reperfusion Injury; Thromboxane B2; Treatment Outcome; Tumor Necrosis Factor-alpha; Varicose Ulcer; Vasomotor System; Wound Healing

This study investigated metabolic and biochemical consequences of colonic ischemia/reperfusion (I/R) in the rat and evaluated whether antioxidants prevent I/R-induced functional damage in the rat colon. The surgical preparation involved a 10 cm segment of the colon and occlusion of the superior mesenteric artery (SMA) to induce I/R. Arterial blood from the aorta and venous blood from the superior mesenteric vein (SMV) was collected to measure blood gases, lactic acid (LA) and arachidonic acid (AA) metabolites. Tissue xanthine oxidase (XO) and thiobarbituric acid (TBA) derivatives were measured before and after reperfusion. In addition, vascular and mucosal permeability, and the effect of MDL 73404 (a water soluble vitamin E analog) and 5-aminosalicylic acid on LA, AA, XO and TBA was measured. After ischemia, the colon displayed a metabolic shift from aerobic to anaerobic course by increasing lactic acid production in the colon (183% increase in SMV lactate level compared 87% in the SMA; p < 0.03). After 10 minutes of reperfusion, circulating 6-keto-prostaglandin F1 alpha increased by 3.85 fold (p < 0.001) and thromboxane B2 increased by 2 to 3 fold. An Ischemia time longer than 60 minutes was required to cause changes in tissue XO levels. Tissue TBA levels showed a good dose response corresponding with I/R time. I/R (60 minutes) caused a three and 16 fold increase (p < 0.01) in vascular and mucosal permeability, respectively. MDL 73404 and 5-aminosalicylic acid significantly inhibited the vascular permeability and decreased LA, AA, XO and TBA. These observations provide the first direct experimental evidence for I/R-induced damage in the colon and some of its effects can be reversed by conventional and novel antioxidants.

Topics: 6-Ketoprostaglandin F1 alpha; Aerobiosis; Aminosalicylic Acids; Anaerobiosis; Animals; Antioxidants; Arachidonic Acid; Colon; Disease Models, Animal; Glutathione; Lactic Acid; Male; Mesalamine; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thiobarbituric Acid Reactive Substances; Thromboxane B2; Vitamin E; Xanthine Oxidase

We investigated the effects of thromboxane (TX) A2 in rats with ischemia-reperfusion-induced intrauterine growth retardation. A saline solution or OKY-046, a selective TXA2 synthetase inhibitor, was injected into the caudal vein of pregnant rats on gestation day 17 before the induction of 60-min uteroplacental ischemia. The fetuses and placentas were delivered and examined on gestation day 21. Blood from the uterine vein of the occluded horn shortly after uteroplacental ischemia was collected, and plasma concentrations of TXB2 and 6-keto-prostaglandin (PG) F1 alpha were determined in the other rats on gestation day 17. Treatment with OKY-046 prevented the ischemia-induced reduction in the fetal body and placental weights. The ratio of 6-keto-PGF1 alpha to TXB2 was significantly increased in the OKY-046-treated group. We conclude that the action of TXA2 might play a salient role in our model.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Embryonic and Fetal Development; Enzyme Inhibitors; Female; Fetal Growth Retardation; Injections, Intravenous; Methacrylates; Pregnancy; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thromboxane B2; Thromboxane-A Synthase

Medium osmolarity sensitively regulates Kupffer cell functions like phagocytosis and prostaglandin (PG) and cytokine production. Betaine and taurine, recently identified as osmolytes in liver cells, interfere with these effects. Because Kupffer cell activation is an important pathogenic mechanism in ischemia-reoxygenation injury, the influence of osmolarity and osmolytes was investigated in a rat liver perfusion model of warm ischemia. Livers were perfused with different medium osmolarities for 60 to 90 minutes in the absence of oxygen, followed by another 90 minutes of reoxygenation. Lactate dehydrogenase (LDH) leakage into the effluent perfusate during the hypoxic and the reoxygenation period was eight- to 10-fold higher with a medium osmolarity of 385 mosmol/L than in normo-osmolarity, and further decreased with hypo-osmolar perfusion buffer. Betaine and taurine addition to the perfusate in near physiological concentrations decreased hypoxia-reoxygenation-induced LDH leakage, aspartate transaminase (AST) leakage, and perfusion pressure increase in hyperosmolar and normo-osmolar perfusions. Stimulation of PGD2, PGE2, thromboxane B2 (TXB2), and tumor necrosis factor alpha (TNF-alpha) release, as well as induction of carbon uptake by the liver during reoxygenation, were suppressed by betaine and taurine, pointing to an interference of these osmolytes with Kupffer cell function. In contrast, endothelial cell function as assessed by hyaluronic acid (HA) uptake was not influenced. It is concluded that warm ischemia-reoxygenation injury in rat liver is aggravated by hyperosmolarity and attenuated by hypo-osmolarity. The osmolytes betaine and taurine have a protective effect, presumably by inhibition of Kupffer cell activation.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspartate Aminotransferases; Betaine; Cytoprotection; Dinoprostone; Hyaluronic Acid; Ibuprofen; In Vitro Techniques; L-Lactate Dehydrogenase; Liver; Male; Osmolar Concentration; Perfusion; Prostaglandin D2; Rats; Rats, Wistar; Reperfusion Injury; Taurine; Thromboxane B2

To study the effects of dl-3-n-butylphthalide (NBP) on the changes of thromboxane B2 (TXB2) and 6-keto-PGF1 alpha (6-keto-PGF1 alpha) contents in hippocampus, striatum, and cerebral cortex of rats subjected to focal cerebral ischemia followed by reperfusion.. Focal cerebral ischemia was induced by inserting a nylon suture into intracranial segment of internal carotid artery from external carotid artery and blockade of the origin of middle cerebral artery. For reperfusion, the suture was pulled out to restore the blood flow to the ischemic brain. Determination of TXB2 and 6-keto-PGF1 alpha was performed by RIA method.. Reperfusion following focal cerebral ischemia resulted in increases in TXB2 at 5 min and 6-keto-PGF1 alpha at 30 min and a decrease in the ratio of epoprostenol (PGI2)/thromboxane A2 (TXA2) (6-keto-PGF1 alpha/TXB2) at 5 min in hippocampus, striatum, and cerebral cortex. NBP 10 mg.kg-1 reduced the content of TXB2 without decreasing effect on 6-keto-PGF1 alpha. NBP 20 mg.kg-1 reduced both TXB2 and 6-keto-PGF1 alpha in lesser extent than aspirin (Asp, 20 mg.kg-1). NBP 20 or 10 mg.kg-1 elevated the ratio of PGI2/TXA2 after reperfusion, but Asp 20 mg.kg-1 did not increase the ratio except in striatum at 5 min after reperfusion.. NBP increases the ratio of PGI2/TXA2 which may have beneficial effects on the impaired microcirculation in postischemic brain tissues.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Aspirin; Benzofurans; Brain; Ischemic Attack, Transient; Neuroprotective Agents; Rats; Reperfusion Injury; Thromboxane B2

Total cardiopulmonary bypass, in an ovine model, is associated with increased pulmonary thromboxane A2 production, cellular sequestration of white cells and platelets, transient pulmonary hypertention, and increased lung lymph flow and lymph protein clearance when compared with respective findings with partial cardiopulmonary bypass. This study evaluates the effect of neutrophil adhesion blockade on lung injury after cardiopulmonary bypass.. Two groups of anesthetized sheep were placed on total cardiopulmonary bypass without assisted ventilation. One group of seven sheep was treated before and during total cardiopulmonary bypass with the neutrophil adhesion blocker NPC 15669. A second group of seven sheep did not receive NPC 15669 treatment before total cardiopulmonary bypass. A third group of seven sheep was treated with NPC 15669 before initiation of partial cardiopulmonary bypass with continued assisted ventilation. Aortic occlusion and hypothermia were not used. After 90 minutes all sheep were separated from cardiopulmonary bypass, with resumption of assisted ventilation and pulmonary arterial flow. After 30 minutes the left atrial pressure was elevated mechanically. Hemodynamics, thromboxane A2 levels, platelet levels, and white blood cell and plasma protein concentrations were measured before cardiopulmonary bypass and afterwards at four 15-minute intervals. Samples were taken from the right and left atria simultaneously. Lung lymph protein levels and flow were measured before and after cardiopulmonary bypass at two 30-minute intervals.. In the total cardiopulmonary bypass group not treated with NPC 15669 signs of lung injury developed after cardiopulmonary bypass. Animals treated with NPC 15669 did not manifest a similar degree of lung injury after either partial or total cardiopulmonary bypass. Increased pulmonary vascular resistance did not develop in treated sheep nor did sequestration of platelets or white blood cells occur. Despite the drug, increased pulmonary capillary permeability after total cardiopulmonary bypass persisted, but was reduced.. Compared with unmodified total cardiopulmonary bypass, blockade of neutrophil adhesion with NPC 15669 reduces, but does not entirely eliminate, lung derangement after total cardiopulmonary bypass.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cardiopulmonary Bypass; Cell Adhesion; Leucine; Lung; Lung Diseases; Neutrophils; Reperfusion Injury; Sheep; Thromboxane B2; Vascular Resistance

It has been suggested that thromboxane A2 (TXA) plays important roles in preservation/reperfusion organ injury. In this report, we investigated the prostanoid release from the liver and the effect of a selective TXA synthetase inhibitor (E)-3-[p-(1H-imidazol-yl-methyl)-phenyl]-2-propenoic acid, OKY046) during cold preservation and after reperfusion. Rat livers were preserved in lactated Ringer's solution at 4 degrees C for 2, 4, and 6 hr and perfused with oxygenated Krebs-Henseleit buffer using recirculating perfusion system, and prostanoids were measured during cold preservation and after reperfusion. OKY046 and a novel TXA receptor antagonist [(9,11), (11,12)-Dideoxa-9a, 11a-dimethyl-methano-11,12-methano-13,14-dihydro-13-aza-14-oxo-15-cyclo pentyl-16,17,18,19,20-pentanor-15-epi-TXA, ONO3708] were added into the preservation solution and perfusate. Along with the preservation time, both the production and release of TXA was observed to increase; however, almost all the produced TXA was stored in the liver tissue. Afterwards, the stored TXA was released into perfusate in 15 min after reperfusion. OKY046 significantly decreased both the production and release of TXA. In addition, OKY046 improved the histological damage and trypan blue uptake of liver cells. Our results demonstrate that TXA, stored in the liver during preservation, might therefore be a potential trigger of reperfusion injury, and as a result, OKY046 reduces reperfusion injury by decreasing the production of TXA during preservation.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acid; Cold Temperature; Endothelium; Enzyme Inhibitors; Liver; Methacrylates; Organ Preservation; Organ Size; Phospholipases A; Rats; Rats, Inbred Lew; Receptors, Thromboxane; Reperfusion Injury; Thromboxane A2; Thromboxane B2; Thromboxane-A Synthase

The pathophysiology of ischemia-reperfusion renal injury is mediated, in part, by the generation of the vasoconstricting prostanoid thromboxane A2 (TXA2). This study was undertaken to evaluate the renoprotective effects, as well as the optimal timing and dosage, of a selective thromboxane synthetase inhibitor, OKY-046, in a unilateral nephrectomized, 60 min ischemia, 72 hr reperfusion, rodent model. Forty-one rats were subjected to right nephrectomy only (group A), or right nephrectomy with 60 min of left renal ischemia and treatment with inactive vehicle only (group B), or 2 mg/kg or 4 mg/kg of OKY-046 administered intravenously before (groups C and D) or after (groups E and F) pedicle clamping. Outcome variables included animal survival; change in kidney weight; 0, 24, and 72 hr plasma creatinine (CR); urea nitrogen (BUN); thromboxane B2 (TXB2) and 6-keto prostaglandin F(1alpha) (6 kPGF(2alpha)) levels; creatinine clearance (CRCL); and histologic evidence of renal injury. Animal survival and postperfusion kidney weight were not significantly different among the groups. However, renal functional parameters were significantly improved with the 2 mg/kg dose of OKY-046 administered after renal ischemia. (group B 72 hr Cr= 8.01 +/- 1.1 mg% vs. group E=3.99 +/- 1.5 mg%, and group B 72 hr BUN=241.3 +/- 32.8 mg% vs. group E=52.6 +/- 22.5 mg%). The CRCL was also improved in group E vs. group B, although these results did not reach statistical significance (group B=0.069 ml/min vs. group E=0.194 ml/ min). The 24 hr TXB2 levels were significantly increased in group B (0 hr=754.1 +/- 219.4 pg/ml vs. 24 hr=2055.9 +/- 550.0 pg/ml), and pre- or posttreatment with OKY-046 abrogated this increase (group C 0 hr=517.1 +/- 80.9 pg/ml vs. 24 hr=384.7 +/- 251.5 pg/ml, and group E 0 hr=781.6 +/- 390.4 pg/ml vs. 24 hr=183.0 +/- 81.4 pg/ml). The 24 hr 6 kPGF(1alpha) levels decreased in all groups, whereas 72 hr 6 kPGF(1alpha) levels increased above baseline in groups A, C, and E, but not in group B. These data demonstrate the beneficial effects of thromboxane A2 synthesis inhibition in the setting of ischemia-reperfusion injury and suggest that this renoprotection correlates with late vasodilatory prostanoid synthesis.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acid; Enzyme Inhibitors; Hot Temperature; Ischemia; Kidney; Male; Methacrylates; Organ Preservation; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thromboxane B2; Thromboxane-A Synthase

There are multiple causes of liver graft nonfunction in the early post-transplant period. Since a severe microcirculatory disturbance based on ischemia-reperfusion liver injury is considered to be the main underlying pathophysiology, it is suspected that various vasoactive substances are liberated after reperfusion of the graft. In order to investigate this matter, we conducted an experimental study with pig liver allotransplantation. Two groups of animals received donor grafts with or without thromboxane synthase inhibitor (sodium ozagrel), 1.25 mg/ kg body weight intravenously, given at the time of liver harvesting. All of the recipient animals in the treatment group (n = 10) survived longer than 7 days whereas three of ten animals in the control group died within 7 days. Serum lactate dehydrogenase (LDH) in the recipient serum at 1 h after reperfusion was significantly lower in the treatment group (915.1 +/- 167.3 U/l) than in the control group (1264.4 +/- 134.7 U/l). Serum thromboxane B2 (2261.7 +/- 1055.7 pg/ml) and endothelin-1 (6.3 +/- 2.2 pg/ml) after reperfusion in the treatment group were significantly lower than those in the control group (4220.0 +/- 1711.0 pg/ml and 11.2 +/- 3.1 pg/ml, respectively). Although serum angiotensin II after reperfusion tended to be lower in the treatment group than in the controls serum renin activity was less than 3 ng/ml in both groups of animals. There were no differences in the plasma endotoxin levels between the two groups. We conclude that the administration of sodium ozagrel to the donor animals provided better graft function in recipients than no such treatment. We speculate that the inhibition of thromboxane A2 production suppresses the liberation of other vasoconstrictive substances, preventing microcirculatory disturbance and, thereby, contributing to improved graft function after liver transplantation.

Topics: Angiotensin II; Animals; Aspartate Aminotransferases; Cardiovascular Agents; Endothelins; Endotoxins; Enzyme Inhibitors; Female; L-Lactate Dehydrogenase; Liver Transplantation; Methacrylates; Prostaglandins F; Reperfusion Injury; Swine; Thromboxane B2; Thromboxane-A Synthase

Eicosanoids play an important role in mediating deleterious effects following skeletal muscle ischemia-reperfusion injury. It has previously been shown that oxygenated perfluorocarbon emulsion (O2 Fluosol-DA 20%) decreases the amount of muscle necrosis and neutrophil sequestration when given during the reperfusion phase following skeletal muscle ischemia. As thromboxane is known to alter the endothelial cytoskeleton, thereby favoring diapedesis of neutrophils, the effects of O2 Fluosol-DA 20% on thromboxane release in a canine gracilis muscle model were investigated. The gracilis muscle on one randomly selected side of 14 adult mongrel dogs (body-weight 22-26 kg) was subjected to 6 h of normothermic ischemia followed by 48 h of normothermic reperfusion. The control group (n = 7) underwent ischemia-reperfusion, but without any pharmacological intervention. The Fluosol group (n = 7) were infused with O2 Fluosol-DA 20% (4.3(0.2) ml O2/100 ml) at 12 ml/min for 40 min via the gracilis artery following the ischemic period. Thromboxane B2 levels were measured from blood samples obtained at pre-ischemia, and at 1 h and 48 h of reperfusion. The gracilis muscles were harvested at the end of the experiment and extent of muscle necrosis quantitated by serial transections, nitroblue tetrazolium staining and computed planimetry. The mean(s.e.m.) muscle necrosis in the control group (59(6)%) was significantly higher than in the Fluosol group (22(5)%, P < 0.05, t-test). Thromboxane levels (pg/ml) in the control group at 1 h of reperfusion were significantly higher than the pre-ischemic and 48-h reperfusion levels (7286(1383) versus 1336(592) and 2314(1297), P < 0.05 by ANOVA and Student-Newman-Keuls test). The thromboxane level in the Fluosol group at 1 h reperfusion was significantly lower than the control group (2700(556) and 7286(1383) pg/ml, respectively; P < 0.05, t-test). In contrast, there was no statistically significant difference between thromboxane levels in the Fluosol group at 1 h reperfusion compared with levels at pre-ischemia and 48 h reperfusion (2700(556) versus 1336(592) and 1400(474). Thus, perfluorocarbons are effective in decreasing skeletal muscle necrosis, probably by maintaining the endothelial integrity and preventing vasospasm, secondary to their inhibitory effect on thromboxane release. Perfluorocarbons may also minimize some of the deleterious pulmonary effects known to be caused by increased levels of eicosanoids during reperfusion.

Topics: Animals; Blood Substitutes; Dogs; Drug Combinations; Eicosanoids; Fluorocarbons; Hydroxyethyl Starch Derivatives; Ischemia; Muscle, Skeletal; Necrosis; Neutrophils; Oxygen Consumption; Reperfusion Injury; Thromboxane B2

We investigated the effects of pretreatment with a potent platelet-activating factor (PAF) receptor antagonist (E5880) on the changes in hepatic and systemic metabolism induced by transient hepatic ischemia and reperfusion. Sixty-five rabbits were assigned to four groups that either did or did not undergo a period of hepatic ischemia and reperfusion with or without pretreatment. E5880 was administered intraportally 1 minute prior to inflow occlusion. Twenty minutes of warm ischemia was followed by 30 minutes of reperfusion. Blood gas analyses and measurements of levels of arterial pyruvate, lactate, and ketone bodies, arterial and portal ammonia and endotoxin, and intrahepatic adenine nucleotide, pyruvate, and lactate were performed. Results were analyzed by either ANOVA or chi-square analysis. Hepatic tissue ATP and energy charge levels were significantly increased and the AMP level was significantly decreased after 30 minutes of reperfusion in the pretreatment group compared to those without pretreatment. At the same time, parameters reflecting hepatic mitochondrial function, such as the arterial ketone body ratio and arterial ammonia level, improved, although they were not statistically significant. No difference was observed for parameters reflecting systemic changes, such as arterial blood gas values and pyruvate and lactate levels. PAF is thought to mediate metabolic changes after hepatic ischemia and reperfusion. PAF released in the liver may exert local effects, which appear to be attenuated by pretreatment with E5880. Systemic metabolic changes seen after hepatic ischemia and reperfusion may be mediated by factors other than PAF.

Topics: 6-Ketoprostaglandin F1 alpha; Adenine Nucleotides; Ammonia; Analysis of Variance; Animals; Blood Gas Analysis; Blood Glucose; Energy Metabolism; Hydrogen-Ion Concentration; Lactic Acid; Liver; Male; Piperidines; Platelet Activating Factor; Pyridinium Compounds; Pyruvic Acid; Rabbits; Reperfusion Injury; Thromboxane B2

This study examines the hypothesis that long-term resuscitation with hyperalimentation (TPN) following acute hemorrhage/reperfusion (H/R) injury stimulates renal release of PGE2. Male Sprague-Dawley rats were anesthetized and subjected to sham or hemorrhage to 30 mmHg for 30 min followed by reperfusion. All rats were placed on TPN for 5 days, then underwent laparotomy for in vivo renal artery and aortic blood flow for 60 min. The kidney was perfused in vitro with Krebs-Henseleit buffer at 3 ml/min (pH 7.4, 37 degrees C) and venous effluent was collected for analysis of PGE2, 6-keto-PGF1 alpha and thromboxane B2 by EIA. Hemorrhage/reperfusion followed by TPN for 5 days increased renal PGE2 2-fold and decreased in vivo renal artery blood flow by 50% compared to the sham group. Hemorrhage/reperfusion followed by TPN did not alter release of the other eicosanoids measured. These data suggest that the kidney has a limited capacity to maintain renal blood flow by increasing release of PGE2 when the animal is subjected to long-term resuscitation with TPN following mild hemorrhage/reperfusion injury.

Topics: Animals; Dinoprostone; Eicosanoids; Hemorrhage; Kidney; Male; Models, Biological; Parenteral Nutrition, Total; Rats; Rats, Sprague-Dawley; Renal Circulation; Reperfusion Injury; Resuscitation; Thromboxane B2; Time Factors; Vasodilator Agents

Myocardial stunning (MS) is a transient contractile dysfunction occurring subsequent to an episode of ischemia followed by reperfusion. NPC 15669 is a leumedin, which inhibits leukocyte adhesion to the endothelium by blocking Mac-1 upregulation. The effect of NPC 15669 supplementation on the hemostasis during MS is unknown. We linked the potential changes in the hemostasis with NPC 15669 therapy during mild MS. Twelve Yorkshire swine underwent coronary artery occlusion for 8 min followed by 90 min of reperfusion. NP 15669 (10 mg/kg loading dose followed by constant infusion a 6 mg kg-1 h-1) was administered to 6 of the animals; another swine received saline and served as the controls. Concentrations of antithrombin III (AT-III), protein C, total protein S, fibronectin, endothelin 1 (ET-1) and the stable metabolites of thromboxane (TxB2) and prostacyclin (6-keto-PGF1 alpha) were measured in the systemic circulation. NPC 15669 therapy was associated with diminished ET-1 (37.4%) and 6-keto-PGF1 alpha (47.1%) levels and increased fibronectin (77.6%) concentrations during MS. There were no changes in the plasma concentrations of TxB2, total protein S, protein C and AT-III in the NPC 15669 group when compared with controls. Mild MS in associated with substantial changes in the hemostatic profile. NPC 15669 administration in a swine model of MS affects certain hemostatic parameters. These data provide support for the involvement of cellular mechanisms in the pathogenesis of MS. The ability of leumedins to modulate hemostasis may have implications for their use in cardiovascular disease.

Topics: 6-Ketoprostaglandin F1 alpha; Analysis of Variance; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antithrombin III; Blood Proteins; Disease Models, Animal; Endothelin-1; Female; Fibronectins; Hemostasis; Leucine; Macrophage-1 Antigen; Myocardial Stunning; Protein C; Protein S; Reperfusion Injury; Swine; Thromboxane B2; Up-Regulation

Topics: Analysis of Variance; Animals; Antioxidants; Dogs; Edema; In Vitro Techniques; Ischemia; Muscle, Skeletal; Necrosis; Peroxidase; Pregnatrienes; Reperfusion; Reperfusion Injury; Steroids, Heterocyclic; Thromboxane B2; Time Factors

The cerebral ischemia rabbit model was made by using the occlusion of four vessels. The results showed that TXB2 and cAMP contents in brain tissues and the latter in plasma markedly increased (P < 0.05, P < 0.01), the 6-keto-PGF1 alpha in brain tissues significantly lowered (P < 0.05) in ischemia formed 30 minutes and 45 minutes after reperfusion. After intravenous injection of Astragalus membranaceus (AM) extracts (3.3 g/kg), Huoxuefang (HXFO and Yiqi Houxue Fang (YQHXF) consisted of AM and HXF before ischemia, the marked increase of TXB2 contents after reperfusion was inhibited (P < 0.05) and the 6-keto-PGF1 alpha in brain tissues after reperfusion were increased (P < 0.01) in HXF and YQHXF group, which change the AM extracts didn't have (P < 0.05). HXF could markedly inhibit the increase of cAMP in brain tissues after reperfusion P < 0.05), while the AM extracts and YQHXF couldn't (P > 0.05). All above-mentioned suggested that the above-mentioned suggested that the balance disorder of TXA2/PGI2 in brain tissues might participate in the occurrence of cerebral reperfusion injury and YQHXF might act against this injury by means of improving the balance of TXA2/PGI2 in brain tissues, which was mainly released by HX drugs of it.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Astragalus propinquus; Brain; Brain Ischemia; Cyclic AMP; Drugs, Chinese Herbal; Female; Male; Rabbits; Reperfusion Injury; Thromboxane B2

The role of eicosanoid metabolism and its relationship with nitric oxide production in the ischemia-reperfusion associated with pancreas transplantation in the rat is explored in this study. Twenty-six male Sprague-Dawley rats were randomized into 3 groups, as follows: group 1, control animals not surgically manipulated; group 2, pancreas transplantation, after 12 hr of organ preservation in University of Wisconsin solution; group 3, same as group 2 but with administration of NG-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor) (10 mg/kg) before organ revascularization. The results show posttransplantation increases in edema and in 6-keto-prostaglandin F1 alpha (x1.9), thromboxane B2 (x4), and prostaglandin E2 (x5) levels in pancreatic tissue. Nitric oxide synthase inhibition reversed the increases in edema and eicosanoid production, which suggests that eicosanoid generation in the recipient rat would be mediated, in part, through a nitric oxide-dependent mechanism.

Topics: Adenosine; Allopurinol; Animals; Arginine; Dinoprostone; Edema; Glutathione; Insulin; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Organ Preservation; Organ Preservation Solutions; Pancreas Transplantation; Prostaglandins F; Raffinose; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thromboxane B2

Topics: Animals; Benzamidines; Dogs; Guanidines; Male; Nitrites; Pancreas; Pancreas Transplantation; Protease Inhibitors; Reperfusion Injury; Thromboxane B2; Transplantation, Autologous

Ischemia-reperfusion injury has been studied in various organs. Effects of leukocyte and platelet depletion on ischemia-reperfusion injury were evaluated using the isolated, perfused dog pancreas in vivo.. Pancreatic exocrine and endocrine functions were stimulated by an intra-arterial injection of cholecystokinin (10(-12) mol) and intravenous injection of glucose and arginine (1 g/kg body wt), respectively. The functions before and after 60 minutes of ischemia were evaluated in the no treatment and in the leukocyte and platelet depletion groups.. Cholecystokinin increased prostaglandin I2 and thromboxane A2 production and stimulated exocrine pancreatic secretion. Glucose and arginine stimulated insulin and glucagon release from the pancreas. Sixty minutes of ischemia followed by 60 minutes of reperfusion damaged the pancreatic acinar and ductular cells. Ischemia of 60 minutes followed by 90 minutes of reperfusion damaged beta cells. Removal of leukocytes (97.6%) and platelets (99.4%) by using a filter throughout the experiment prevented the ischemia-reperfusion injury, reduced plasma lipid peroxide and thromboxane A2, and increased prostaglandin I2 levels.. Leukocytes and platelets seem to damage the pancreas during ischemia-reperfusion by increasing the peroxidation of structurally important cell membrane lipids and reduced the thromboxane A2 prostaglandin I2 ratio, a predictor of cellular injury.

Topics: 6-Ketoprostaglandin F1 alpha; Amylases; Animals; Blood Platelets; Dogs; Female; In Vitro Techniques; Ischemia; Leukocyte Count; Leukocytes; Lipid Peroxides; Male; Pancreas; Pancreatic Hormones; Platelet Count; Reperfusion Injury; Thromboxane B2; Veins

Prostaglandins are widely known to have cytoprotective effects in a variety of conditions. Thromboxane A2 has the opposite effect of prostaglandins. In this study the effects of the thromboxane A2 receptor antagonist ONO 3708 on ischemia and subsequent reperfusion in the dog liver was evaluated.. Mongrel dogs weighing from 10 to 15 kg were divided into three groups: a control group, a group with induced liver ischemia and subsequent reperfusion, and a group that received ONO 3708 and then underwent induced liver ischemia and subsequent reperfusion. Liver ischemia was induced by the Pringle procedure for 60 minutes. The concentrations of total free amino acids, aromatic amino acids, and branched-chain amino acids in blood taken from the portal and hepatic veins were examined before and after the Pringle procedure in the latter two groups and at the corresponding points in the control group.. Disturbances in amino acid metabolism in the liver occurred 5 minutes after the declamping in the ischemic group, and prostaglandin I2 and thromboxane A2 levels and lipid peroxide production, were increased. In contrast, hepatic amino acid metabolism was unchanged, and prostaglandin I2 and thromboxane A2, and lipid peroxide production, were normalized in the group that was treated with ONO 3708.. ONO 3708 appears to protects hepatic tissue from ischemia-reperfusion injury through free-radical scavenging, by increasing prostaglandin I2 levels, and by decreasing thromboxane A2 production.

Topics: 6-Ketoprostaglandin F1 alpha; Amino Acids; Animals; Dogs; Hepatic Veins; Lipid Peroxides; Liver; Portal Vein; Receptors, Thromboxane; Reperfusion Injury; Thromboxane A2; Thromboxane B2

We have established that thromboxane B2 (TX) blood levels increase across the pulmonary circulation after total cardiopulmonary bypass (CPB) but not after partial CPB. In the present study, we used the same model and examined the parameters of pulmonary injury after total or partial CPB.. Fourteen anesthetized sheep were placed on total CPB (n = 7), without ventilation and with occlusion of the pulmonary artery, or partial CPB (n = 7), with ventilation and an open pulmonary artery. After 90 minutes, the sheep were separated from CPB, and the pulmonary artery was perfused normally. After 30 minutes, we elevated left atrial pressure in all sheep. Plasma TX, plasma leukotriene B4, platelet counts, white blood cell counts, and plasma protein concentration were measured before CPB and every 15 minutes after CPB for 1 hour. The right and left atrial blood samples were obtained simultaneously. Pulmonary arterial pressure, left atrial pressure, and pulmonary arterial flow were measured. Pulmonary vascular resistance (PVR) was calculated for 30 minutes after CPB. Lung lymph protein, TX, leukotriene B4, and flow were measured before CPB and every 30 minutes after CPB for 1 hour. Pulmonary biopsies and bronchoalveolar lavage fluid were obtained before CPB and at the end of the experiment. After total CPB, levels of TX across the pulmonary circulation increased significantly, but leukotriene B4 remained constant. Platelets and white blood cells were consumed across the pulmonary circuit after total CPB but not after partial CPB. PVR increased by 170%, lymph flow increased by 233%, lung water content increased by 15%, and the ratio of lymph to plasma protein decreased by 20% after total CPB, but similar changes did not occur after partial CPB.. During total CPB, the lungs are totally dependent on oxygen supply provided by nonpulsatile bronchial arterial flow. Lung injury seen with restoration of pulmonary artery flow and ventilation may be the result of an inflammatory response associated with TX elevation after a period of relative pulmonary ischemia. Pulmonary injury was not seen after less severe pulmonary arterial flow deprivation, with maintenance of ventilation (partial CPB). Although the specific cause is undetermined from these data, the occurrence of elevated TX levels and lung damage after total CPB is clearly established.

Topics: Animals; Cardiopulmonary Bypass; Leukocyte Count; Leukotriene B4; Lung; Lymph; Platelet Count; Pulmonary Circulation; Reperfusion Injury; Sheep; Thromboxane B2; Time Factors

Six patients undergoing vascular reconstructive surgery were examined for evidence of oxygen-derived free radical (ORF) damage to the protein, immunoglobulin G (IgG). OFR damage was determined as an increase in the fluorescence (ex 360 nm em 454 nm) to ultraviolet absorption (280 nm) ratio of IgG, representing N-Formyl kynurenine and other as yet unidentified fluorophores. The IgG ratio was found to increase slightly during ischaemia and to undergo marked elevation upon reperfusion (275 +/- 405% baseline value at 40 min post-clamp; mean +/- sd). A high ratio was maintained post-reperfusion, even after 60 min reperfusion. Determination of thromboxane B2, (TXB2), leukotriene B4, (LTB4) and 6-keto prostaglandin F1 alpha, (PGF1a), revealed a decrease in their concentrations during ischaemia and a transient, marked increase on reperfusion. Only TXB2 concentrations were found to correlate with the IgG ratio (negative correlation, p < 0.05). No correlation was observed between von Willebrand antigen factor, a marker of endothelial cell damage and fluorescent IgG ratio. However, levels of the factor increased slightly during ischaemia and more sharply upon reperfusion. These preliminary results therefore suggest that a more likely source of the OFRs responsible for IgG damage is endothelial cell xanthine oxidase, rather than cyclo-oxygenase or lipoxygenase.

Topics: Aged; Free Radicals; Humans; Immunoglobulin G; Ischemia; Leg; Leukotriene B4; Middle Aged; Prostaglandins F; Reperfusion Injury; Thromboxane B2; Vascular Surgical Procedures; von Willebrand Factor

Effects of prostaglandin (PG) E1 on ischemia-reperfusion (I-R) injury to the pancreas was evaluated using isolated in vivo perfused dog pancreas. Pancreatic endocrine and exocrine functions were stimulated with 10(-12) M cholecystokinin octapeptide (CCK-8). This amount of CCK-8 promoted production of insulin, glucagon, PGI2, and thromboxane (Tx) A2 in the pancreas. Sixty minutes of ischemia and subsequent reperfusion induced damage to pancreatic ductular, acinar, and beta cells. Intra-arterial administration of PGE1 at a dose of 0.5 microgram/kg/min throughout the experiment prevented the I-R injury, reducing plasma lipid peroxides, and elevating PGI2 without changing TxA2 in the pancreas. PGE1 thus appears to protect pancreatic function from I-R injury both by depressing the effect of free-radicals and by decreasing TxA2/PGI2 which predicts cell injury.

Topics: 6-Ketoprostaglandin F1 alpha; Alprostadil; Animals; Dogs; Female; Glucagon; Insulin; Lipid Peroxides; Male; Pancreas; Reperfusion Injury; Thromboxane B2

Thromboxane A2, leukotriene B4, and NE are all released from ischemic muscle during reperfusion. Thromboxane A2 levels peaked at 10 min and this potent vasoconstrictor may be responsible for low reflow. Neutrophil elastase levels did not rise until 240 min of reperfusion, following that of leukotriene B4 at 120 min, indicating that neutrophil recruitment and activation is a relatively late event following revascularization. In conclusion, it would appear that endothelial factors have a significant role in the vasomotor changes that account for low reflow. Equally altered neutrophil function almost certainly contributes to the final development of reperfusion injury.

Topics: Animals; Endothelium, Vascular; Ischemia; Leukocyte Elastase; Leukotriene B4; Muscles; Neutrophils; Pancreatic Elastase; Rats; Regional Blood Flow; Reperfusion Injury; Thromboxane B2

To evaluate the role of thromboxane A2 (TXA2) in ischemic liver injury, the serum changes in thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-K-PGF1 alpha) following warm ischemia of the total canine liver were examined, and the protective effect of a TXA2 synthetase inhibitor was assessed. Total liver ischemia was performed for 60 min on two groups of dogs: a control group, in which ischemia alone was performed, and an OKY-046 group, which received a TXA2 synthetase inhibitor. A temporary active portacaval shunt was used to eliminate the effects of splanchnic venous stasis during clamping of the hepatic pedicle. Postoperative changes in liver function, assessed by the transaminase enzyme levels, and in prostaglandins were recorded and the histologic liver findings of both groups 1 week after ischemia were compared. The levels of 6-K-PGF1 alpha increased after reperfusion in both groups, while those of TXB2 increased in the control group but maintained low levels in the OKY-046 group. Liver function was better and histologic changes less marked in the OKY-046 group than in the control group, suggesting the important role of TXA2 in ischemic liver injury and the usefulness of a TXA2 synthetase inhibitor for protecting the liver against ischemic injury.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Aspartate Aminotransferases; Dogs; Ischemia; L-Lactate Dehydrogenase; Liver; Liver Function Tests; Liver Transplantation; Methacrylates; Organ Preservation; Reperfusion Injury; Thromboxane B2; Thromboxane-A Synthase

Bronchial arterial (BA) perfusion could modify pulmonary arterial (PA) ischemia-reperfusion (IR) injury by promoting clearance of peribronchial edema or limiting edema formation through maintenance of pulmonary vessel integrity via bronchopulmonary anastomotic or pulmonary vasa vasorum flow. The purpose of this study was to determine the effect of BA perfusion on IR injury in isolated sheep lungs. In 12 lungs (BA++) the BA was perfused throughout 30 min of PA ischemia and 180 min of reperfusion. In 12 lungs (BA-+) BA perfusion was begun with PA reperfusion, and in 15 lungs (BA--) the BA was never perfused. After 180 min, extravascular lung water was less (P < 0.05) in BA++ and B-+ lungs [4.70 +/- 0.16 and 4.57 +/- 0.18 g/g blood-free dry lung (bfdl)] than in BA-- lungs (5.23 +/- 0.19 g/g bfdl). The reflection coefficient for albumin was greater (P < 0.05) in BA++ and BA-+ (0.57 +/- 0.06 and 0.75 +/- 0.03) than in BA-- lungs (0.44 +/- 0.04). The filtration coefficient in BA++ and BA-+ lungs (0.016 +/- 0.006 and 0.015 +/- 0.006 g.min-1 x mmHg-1 x kg-1) was not different from that in BA-- lungs (0.025 +/- 0.006 g.min-1 x mmHg-1 x kg-1). These results suggest that BA perfusion decreased reperfusion edema by attenuating the increase in pulmonary vascular permeability caused by IR injury. Moreover the result in BA-+ lungs suggests that the protective effect was mediated by BA perfusion of PA vasa vasorum rather than bronchopulmonary anastomotic flow, which was trivial compared with PA blood flow.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Bronchi; Bronchial Arteries; Capillary Permeability; Extravascular Lung Water; Ischemia; Lung; Lymphatic System; Pulmonary Circulation; Pulmonary Edema; Regional Blood Flow; Reperfusion Injury; Respiration, Artificial; Sheep; Thromboxane B2; Water-Electrolyte Balance

The role of endogenous splanchnic eicosanoids in mediating splanchnic vasoconstriction induced by the leukotriene C4 (LTC4) was examined during mild hemorrhage/reperfusion injury. Male Sprague-Dawley rats were anesthetized and subjected to sham or acute hemorrhage for 30 minutes, to 30 mm Hg, followed by blood reperfusion (SK+R). The superior mesenteric artery was cannulated and removed with its end-organ intestine (SV+SI preparation) and perfused in vitro with oxygenated Krebs-Henseleit buffer. Perfusion pressure was constantly recorded. Net SV+SI release of 6-keto-PGF1 alpha, PGE2 and thromboxane B2 were analyzed by enzyme immunoassay after LTC4 stimulation. Leukotriene C4 increased perfusion pressure and decreased the ratio of 6-keto-PGF1 alpha to thromboxane release (but not PGE2 to thromboxane B2) in the sham group. Hemorrhage/reperfusion increased perfusion pressure and decreased the ratio of 6-keto-PGF1 alpha to thromboxane B2. Mild hemorrhage/reperfusion increased LTC4-induced splanchnic vasoconstriction in part by decreasing the release ratio of endogenous splanchnic PGI2 to thromboxane B2.

Topics: Analysis of Variance; Animals; Hemorrhage; Immunoenzyme Techniques; Leukotriene C4; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Splanchnic Circulation; Thromboxane B2; Vasoconstriction

Superoxide dismutase (SOD) is a potent scavenger of superoxide radicals produced during normothermic ischemia-reperfusion. Since it has a short half-life, its optimal effect is achieved when it is given prior to reperfusion. The inclusion of SOD in liposomes (lipo-SOD) prolongs its half-life (free SOD: 6 min; lipo-SOD: 4 h). The protective effect of lipo-SOD in a 60-min bilateral renal warm ischemia model was studied. We divided 60 male Wistar rats between two control groups and five study groups according to the drug used (SOD or lipo-SOD) and to the time of SOD administration (prior to ischemia or prior to reperfusion). SOD and lipo-SOD were both given at 20 mg/kg endovenously. Weight, diuresis, creatinine per 100 g (Cr/100 g), and creatinine clearance per 100 g (CrCl/100 g) were studied. Conventional renal histology was performed after reperfusion and on day 7. Renal malondialdehyde, 6 keto PGF 1 alpha, and TxB2 tissue levels were studied after reperfusion. Results showed that the renal protective effect of free SOD on warm ischemic-reperfusion injury depended on the time of administration, being more effective when given before reperfusion. On the other hand, the renal protective effect of liposomed SOD did not depend on the time of administration since efficacy was similar when given before reperfusion or before ischemia. The functional protective effect of liposomed SOD was similar to that of free SOD when they were given prior to reperfusion. Nevertheless, since histological damage observed with liposomed SOD was less than with free SOD, it is suggested that the liposomed galenic form may offer better protection against renal warm ischemia. In addition, liposomed SOD was better at preventing tissue prostanoid generation after renal warm ischemic-reperfusion injury than free SOD. We concluded that liposomed SOD shows a higher renal protective effect against warm ischemia than free SOD.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Creatinine; Drug Carriers; Free Radical Scavengers; Ischemia; Kidney; Liposomes; Male; Malondialdehyde; Rats; Rats, Wistar; Reperfusion; Reperfusion Injury; Superoxide Dismutase; Thromboxane B2

Arachidonate metabolites have been implicated in the development of cerebral injury after ischemia. Particular importance has been placed on the balance of thromboxane A2 and prostaglandin I2 because of its regulative activity on platelet functions and arterial tone. The purpose of the present study was to shed light on the role of thromboxane A2 in postischemic brain injury.. We evaluated the effects of S-1452, a novel thromboxane A2 receptor antagonist, on brain edema, infarct areas, and survival rate in rats with middle cerebral artery occlusion. A transient middle cerebral artery occlusion model was produced by inserting a piece of silicon-coated nylon thread into the internal carotid artery.. The ratio of plasma thromboxane B2 to 6-keto-prostaglandin F1 alpha significantly rose at 0 hour (P < .05), 1 hour (P < .01), 3 hours (P < .05), and 12 hours (P < .05) and then nearly returned to the normal level at 24 hours after reperfusion following 1-hour occlusion. Pretreatment with S-1452 (5, 10, or 50 mg/kg PO) significantly attenuated the increase in postischemic water content in the cerebral cortex perfused by the anterior cerebral artery and the cerebral cortex perfused by the middle cerebral artery in a dose-dependent manner but slightly attenuated it in the caudate putamen 24 hours after reperfusion following 1-hour occlusion. Pretreatment with S-1452 (10 mg/kg PO) also significantly decreased the areas of infarction in the front parts of the cerebrum. The survival rate of animals after 2 hours of occlusion tended to be improved by treatment with S-1452 (10 mg.kg-1.d-1 PO), although there was no statistical significance.. Our results suggest that thromboxane A2 is closely related to postischemic brain injury in the early phase of recirculation and that S-1452 may have a protective effect on postischemic brain injury.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Body Water; Brain; Bridged Bicyclo Compounds; Cerebral Infarction; Fatty Acids, Monounsaturated; Ischemic Attack, Transient; Male; Rats; Rats, Wistar; Receptors, Thromboxane; Reperfusion Injury; Survival Analysis; Thromboxane A2; Thromboxane B2; Time Factors

The role of mast cells in pulmonary artery occlusion/reperfusion injury was examined. Lung tissue was obtained from dogs after left pulmonary artery occlusion for 48 h (n = 5) or after similar occlusion followed by 4 h of reperfusion (n = 11). By light microscopy and morphometry, the percentage of mast cells increased 2.4-fold (p < 0.05) in nonoccluded right lungs and 2.9-fold (p < 0.05) in occluded left lungs without reperfusion compared with that in control lungs. After reperfusion, the occluded left lung contained 1.8-fold (p < 0.05) as many mast cells as the nonoccluded right lung and 4.2-fold (p < 0.05) more than that in control lungs. Hydroxyurea did not significantly affect the number of mast cells observed in the right and left lungs after ischemia/reperfusion; 39.8% and 54.4% of the mast cells were degranulated in nonoccluded right lung and occluded left lung preparations, respectively, after left pulmonary artery ischemia/reperfusion (each, p < 0.05 compared with control lungs). The release of eicosanoids into the airways during ischemia/reperfusion injury was also examined. Thromboxane B2 and leukotriene B4 were markedly increased (each, p < 0.05 compared with that in control lungs) in bronchial lavage fluids from both nonoccluded and occluded lungs compared with sham-occluded lungs. Thus, mast cell recruitment and degranulation may play a role in lung ischemia/reperfusion injury.

Topics: Animals; Arterial Occlusive Diseases; Bronchoalveolar Lavage Fluid; Cell Count; Cell Degranulation; Dogs; Hydroxyurea; Leukotriene B4; Lung; Mast Cells; Microscopy, Electron; Pulmonary Artery; Reperfusion Injury; SRS-A; Thromboxane B2; Time Factors

Polymorphonuclear leukocyte (PMN) sequestration within the pulmonary microvasculature is known to occur in association with ischemia/reoxygenation (I/R). This sequestration is dependent on eicosanoids and reactive oxygen species. PMN sequestration within the lungs suggests that pulmonary microvascular endothelial cells (MECs) may in part regulate the I/R response. Simulating I/R, we examined the effect of hypoxia/reoxygenation (H/R) on pulmonary MECs in vitro, with and without PMNs. Significant cellular injury, assessed by 51Cr release, occurred upon reoxygenation of MECs (P < .01). Addition of PMNs to the H/R-injured monolayers did not increase MEC injury. Reoxygenation of MECs also resulted in increased thromboxane (Tx) B2 production compared to controls (P < .01). Inhibition of Tx secretion by aspirin reduced H/R-induced PMN adhesion to MECs (P < .01). Furthermore, H/R-induced increases in PMN-MEC adhesion were prevented by allopurinol and superoxide dismutase (P < .01). These data suggest that the pulmonary response to H/R is mediated by MEC generation of reactive oxygen radical species and Tx, which promotes increased PMN adhesion.

Topics: Actins; Allopurinol; Animals; Cattle; Cell Adhesion; Cells, Cultured; Chromium Radioisotopes; Cytoskeleton; Dexamethasone; Eicosanoids; Endothelium, Vascular; Hypoxia; Leukotriene B4; Lung; Masoprocol; Microcirculation; Neutrophils; Radioimmunoassay; Reactive Oxygen Species; Reperfusion Injury; Superoxide Dismutase; Thromboxane B2; Xanthine Oxidase

Aortic aneurysm repair produces inflammatory mediators, neutrophil activation, and remote organ injury. Reperfusion plasma from these patients produces microvascular injury in an ex vivo chemotactic model. This study investigates the mechanism of this injury. Vena caval blood was obtained before and 15 minutes after aortic clamp removal (n = 16) or at laparotomy (n = 10). Plasma or saline solution was introduced into unit dose chambers fixed atop dermabrasions on the back of depilated anesthetized rabbits. Animals were treated with intravenous saline solution (n = 4); made neutropenic with nitrogen mustard (n = 4); pretreated with the xanthine oxidase inhibitor allopurinol (n = 4); or cotreated intravenously with the free radical scavengers superoxide dismutase (SOD) and catalase (n = 4). Three hours later neutrophil counts (polymorphonuclear cells [PMN]/mm3) and activity (free radical production by flow cytometry), protein leakage, and inflammatory mediators (thromboxane [TX] and leukotriene B4 [LTB4]) were measured. In contrast to control plasma in untreated rabbits, reperfusion plasma produced TX and LTB4 generation (1090 +/- 105 and 794 +/- 91 pg/ml, respectively, p < 0.01), PMN accumulation (1636 +/- 210/mm3, p < 0.01) and activation (276 +/- 31 mean fluorescent units), and microvascular permeability (554 +/- 90 micrograms/ml, p < 0.01). Neutropenia (3 +/- 1 PMN/mm3) and cotreatment with SOD and catalase abolished these responses, whereas pretreatment with allopurinol did not. Human reperfusion plasma contains a soluble factor that stimulates free radical generation by rabbit neutrophils to produce a microvascular injury characterized by de novo TX production, neutrophil accumulation and activation, and increased microvascular permeability to protein.

Topics: Allopurinol; Animals; Aortic Aneurysm, Abdominal; Catalase; Cell Movement; Chemotaxis, Leukocyte; Dermabrasion; Humans; Inflammation; Leukocyte Count; Leukotriene B4; Male; Neutrophils; Proteins; Rabbits; Reperfusion Injury; Skin; Superoxide Dismutase; Thromboxane B2

Exposure of isolated perfused rabbit lungs (IPL) to ischemia-reperfusion causes a transient increase in pulmonary arterial (PA) pressure at the onset of reperfusion. Because thromboxane A2 (TxA2) is a potent vasoconstrictor, we hypothesized that it may contribute to the ischemia-reperfusion-induced pressor response. To evaluate this hypothesis, we exposed IPL perfused with a cell-free solution to 40 min of warm ischemia followed by reperfusion and measured perfusate immunoreactive thromboxane B2 (iTxB2) and 6-ketoprostaglandin F1 alpha (i6-keto-PGF1 alpha). We observed that ischemia-reperfusion IPL compared with controls had an increase in PA pressure (40.2 +/- 4.8 vs. 9.3 +/- 0.3 mmHg, P < 0.05), lung edema (29.3 +/- 6.3 vs. -0.2 +/- 0.2 g, P < 0.05), iTxB2 perfusate levels (155 +/- 22 vs. < 50 pg/ml, P < 0.05), and i6-keto-PGF1 alpha (436 +/- 33 vs. 61 +/- 16 pg/ml, P < 0.05). In ischemia-reperfusion IPL, infusion of SQ 29548 (10(-6) M), a specific TxA2/prostaglandin H2 receptor antagonist, attenuated the PA pressor response and the degree of edema. We conclude that pulmonary hypertension associated with ischemia-reperfusion results in part from pulmonary release of TxA2. Furthermore, TxA2 directly through membrane effects or indirectly through hydrostatic mechanisms increases the severity of ischemia-reperfusion-induced lung edema.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Bridged Bicyclo Compounds, Heterocyclic; Fatty Acids, Unsaturated; Hydrazines; Hypertension, Pulmonary; In Vitro Techniques; Ischemia; Lung; Organ Size; Pulmonary Circulation; Pulmonary Edema; Rabbits; Radioimmunoassay; Receptors, Thromboxane; Reperfusion Injury; Thromboxane A2; Thromboxane B2; Thromboxanes; Vasoconstriction

Interleukin-1 and thromboxane are known to mediate the host response to sepsis, trauma, and myocardial ischemia. A well-established model of canine isolated gracilis muscle was used to evaluate whether cytokine (interleukin-1) played a role in skeletal muscle ischemia-reperfusion injury. Six adult mongrel dogs (25-30 kg) were subjected to six hours of muscle ischemia followed by reperfusion. Gracilis venous samples were collected pre-ischemia and at one hour of reperfusion. Systemic (arterial) blood samples were taken at one hour of reperfusion. Sera were analyzed for interleukin-1 by bioassay and thromboxane (B2) by radio-immunoassay. The gracilis muscle of the operated limb was harvested in all the animals for assessment of the percentage of muscle necrosis. This was found to be 56.2 +/- 14.8% by serial transections, nitroblue tetrazolium staining, and computerized planimetry. Interleukin-1 levels in the gracilis venous effluent increased from 21.88 +/- 7.13 units/ml during pre-ischemic baseline to 50.42 +/- 9.12 units/ml after six hours of ischemia followed by one hour of reperfusion (p less than 0.04). Thromboxane B2 levels were 2983 +/- 1083 pg/ml and 9483 +/- 2218 pg/ml at pre-ischemia and at one hour of reperfusion respectively (p less than 0.04). Systemic levels of both interleukin-1 and thromboxane B2 at one hour of reperfusion were 0 units/ml and 1584 +/- 520 pg/ml respectively, which were significantly lower than the one hour reperfusion gracilis venous effluent levels (p less than 0.04). This is the first report in which cytokines have been implicated in skeletal muscle ischemia-reperfusion injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Biological Assay; Disease Models, Animal; Dogs; Hindlimb; Interleukin-1; Ischemia; Muscles; Radioimmunoassay; Reperfusion Injury; Thromboxane B2

This study was carried out to investigate the proportion of the 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) and thromboxane B2 (TXB2) alteration that is due to ischemia in pancreas transplantation against the proportion due to reperfusion. For this purpose, Lewis rats were divided in three experimental groups: Group I = Control, Group II = Donor pancreas subjected to 15 minutes of cold ischemia, Group III = Same as group II but pancreas were transplanted to the recipient individual and then subjected to reperfusion. The results indicate that increases in pancreas 6-keto PGF1 alpha occur as a consequence of cold ischemia while TXB2 remains unchanged. When blood flow was restored, 6-keto PGF1 alpha remained unchanged compared to the ischemic group while pancreatic levels of TXB2 were significantly increased. These results suggest a different induction of prostanoid metabolism during ischemia and reperfusion in pancreatic tissue.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Ischemia; Male; Organ Preservation; Pancreas; Pancreas Transplantation; Rats; Rats, Inbred Lew; Reperfusion Injury; Thromboxane B2

Thirty three New Zealand rabbits were randomly divided into three groups, i.e. the control group, the high atmospheric pressure. (HAP) group and the hyperbaric oxygenation (HBO) group. The experimental animals were made into the models of reperfusion for acute incomplete cerebral ischemia. The blood-gas analyses drawn from the common carotid arteries and the internal jugular veins were carried out, and the 6-keto-PGF1a and TXB2 in the brain tissues determined. The results showed that the contents of 6-keto-PGF1a in the brain tissues of the HBO groups were significantly increased (P less than 0.01). While those of TXB2 were significantly decreased (P less than 0.01). The po2 in both the arterial and the venous blood were obviously elevated in the HBO group. Pathological examination showed that the brain tissue damages in the HBO group were the slightest among the three groups. It was postulated that the effect of HBO on 6-keto-PGF1a and TXB2 might reflect one of the mechanisms of HBO for the treatment of acute cerebral ischemia.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Gas Analysis; Brain Ischemia; Hyperbaric Oxygenation; Rabbits; Reperfusion Injury; Thromboxane B2

1. The burst of damaging oxygen free-radicals at the time of reperfusion is one of the crucial factors affecting skin flap survival after an ischaemic interval. In these experiments the efficacy of the antioxidant and free-radical scavenger N-acetylcysteine in improving the survival of ischaemic rabbit epigastric skin flaps was tested. 2. At the time of reperfusion flaps were given: (1) balanced salt solution by intravenous whole-body administration, (2) N-acetylcysteine (200 mg/kg) by intravenous whole-body administration, (3) balanced salt solution by intra-arterial infusion into the flap, (4) N-acetylcysteine (20 mg/kg) by intra-arterial infusion into the flap, or (5) N-acetylcysteine (200 mg/kg) by intra-arterial infusion into the flap. Flap survival at 1 week, and tissue levels of parameters related to free-radical production, blood levels of thromboxane B2 and peripheral resistance during reperfusion were determined. 3. Compared with controls (groups 1 and 3) which had flap survival rates (expressed as percentage surface area surviving) of 27.1% and 31.6%, respectively. N-acetylcysteine treatment in group 2 (55.2%) and group 4 (51.9%) resulted in significant (P less than 0.05) improvements in flap survival. The survival rate in group 5 (37.7%) was not significantly better than that of the controls. 4. N-Acetylcysteine significantly reduced parameters related to free-radical production in the skin flap after 30 min of reperfusion, determined as tissue levels of malonyldialdehyde and protein oxidation products. There was also a significant decrease in peripheral resistance when low-dose N-acetylcysteine (group 4) was infused intra-arterially into the flap.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acetylcysteine; Animals; Antioxidants; Disease Models, Animal; Free Radical Scavengers; Graft Survival; Ischemia; Malondialdehyde; Phenylhydrazines; Rabbits; Reperfusion Injury; Skin; Surgical Flaps; Thromboxane B2; Vascular Resistance

Derivatives of arachidonic acid have been found to play a role in the reperfusion injury of various tissues. These compounds have a broad spectrum of activity, including modulation of white blood cell response to injured tissue. This study was designed to determine the effect of thromboxane and lipoxygenase derivatives on the local and systemic response to ischemia and reperfusion of skeletal muscle. Fifteen dogs were separated into three groups and subjected to gracilis muscle ischemia followed by 2 hours of reperfusion. One group served as controls, one group was treated with OKY-046 (a thromboxane synthetase inhibitor), and one group was treated with diethylcarbamazine (a lipoxygenase inhibitor). White blood cell activation as measured by superoxide anion production, and eicosanoid levels were measured both in the gracilis venous effluent and central venous circulation. These results were compared to infarct size in the gracilis muscle. OKY-046 significantly reduced thromboxane production in both the central venous (102 +/- 30 to 31 +/- 9 pg/ml, p less than 0.05) and gracilis samples (107 +/- 22 to 25 +/- 6 pg/ml, p less than 0.005). This was accompanied by a reduced white cell activation in the central venous blood (15 +/- 1 to 10 +/- 1 nmol O2-, p less than 0.05), but did not affect infarct size or white cell activation in the gracilis. Conversely, diethylcarbamazine significantly reduced both white cell activation (16 +/- 1 to 10 +/- 1 nmol O2-, p less than 0.005) and infarct size in the gracilis muscles (61.6% +/- 4.5% to 28.5% +/- 8.6%, p less than 0.01), as well as reduced systemic white blood cell activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acids; Cell Survival; Diethylcarbamazine; Dogs; Female; Ischemia; Leukotriene B4; Male; Methacrylates; Muscles; Neutrophils; Reperfusion Injury; Superoxides; Thromboxane B2; Thromboxane-A Synthase

The effects of platelet-activating factor (PAF) on prostanoid release during mesenteric ischemia-reperfusion-induced shock were investigated in anesthesized dogs 1) by measuring plasma levels of prostaglandin (PG)F2 alpha, 6-keto-PGF1 alpha and thromboxane (TX)B2 in the superior mesenteric vein during reperfusion following 2 hr occlusion of the superior mesenteric artery; 2) by monitoring the effects of BN 52021, a specific PAF receptor antagonist and indomethacin on hemodynamic parameters and prostanoid levels; and 3) by studying circulatory responses to PAF and PGF2 alpha injected into the superior mesenteric vein in the presence of BN 52021 or indomethacin. Restoration of the blood flow following 2 hr ischemia resulted in an immediate dramatic decrease in mean arterial blood pressure, with a concomitant increase in mean portal venous pressure, hematocrit values, and plasma prostanoid levels. Pretreatment of the animals either with BN 52021 (4 mg.kg-1) or indomethacin (2 mg.kg-1 plus 3 mg.kg-1hr-1) prevented the circulatory collapse and the increase in prostanoid levels during reperfusion. Administration of exogenous PAF (0.1 micrograms.kg-1) or PGF2 alpha (10 micrograms.kg-1) into the superior mesenteric vein evoked hypotension similar to that observed during reperfusion. Pretreatment of the animals with BN 52021 completely prevented the effects of PAF but failed to modify the responses to PGF2 alpha. Indomethacin at a dose that inhibited prostanoid formation was highly effective to attenuate the hypotensive response to exogenous PAF. These data suggest that prostanoid formation may be secondary to PAF release in circulatory collapse evoked by intestinal ischemia-reperfusion and give further support to the notion of the importance of PAF prostanoid interaction during ischemia-reperfusion-induced shock.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Dinoprost; Diterpenes; Dogs; Ginkgolides; Hemodynamics; Indomethacin; Lactones; Male; Mesenteric Arteries; Mesenteric Veins; Platelet Activating Factor; Prostaglandins; Reperfusion Injury; Shock; Thromboxane B2

The present study was designed to determine whether the administration of superoxide dismutase (SOD) can alleviate ischemic kidney damage and whether there is a relationship between oxygen free radicals and thromboxane (Tx). In 17 dogs, the right kidney was removed and the vascular pedicle of the left kidney was clamped for 75 min. Prior to reperfusion, the ischemic kidney was rinsed with 5 mg SOD and an additional 20 mg SOD was infused systemically. Blood samples were drawn from the renal vein before ischemia and after reperfusion to determine serum levels of thromboxane B2 (TxB2). All eight untreated dogs died within 1 week of renal failure, and the nine treated dogs demonstrated transient renal failure, with a significant difference (P less than 0.001) being found between the two groups. A significant difference (P less than 0.001) in TxB2 levels was found in the untreated dogs before and after ischemia and between the two groups following reperfusion. Animals that are treated with SOD after the ischemic event has occurred but before reperfusion exhibit a favorable clinical course in terms of survival and renal function. Tx synthesis in the kidney can be blocked by the administration of SOD.

Topics: Animals; Dogs; Free Radicals; Kidney; Oxygen; Prostaglandins; Reperfusion Injury; Superoxide Dismutase; Thromboxane B2

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Free Radicals; Lipid Peroxidation; Male; Pancreas; Pancreas Transplantation; Phospholipases A; Phospholipases A2; Rats; Rats, Inbred Lew; Reperfusion Injury; Superoxide Dismutase; Thromboxane B2

1. Biochemical mechanisms of ischaemia were investigated in rabbit skin flaps subjected to 2 h of primary ischaemia then, 24 h later, to 4 h of secondary ischaemia. During secondary ischaemia, flaps underwent either total ischaemia (arterial and venous blood supply occluded) or partial ischaemia (vein only occluded). Some of these flaps were treated at the time of reperfusion with the free-radical scavenger superoxide dismutase (EC 1.15.1.1) and/or the thromboxane synthetase inhibitor UK-38,485. 2. After 30 min of reperfusion, superoxide dismutase treatment significantly reduced blood thromboxane levels, elevated during ischaemia. Superoxide dismutase also reduced tissue levels of malonyldialdehyde and xanthine oxidase, indicators of free-radical damage, and restored the depleted tissue levels of superoxide dismutase. 3. UK-38,485 treatment failed to significantly alter any of these tissue free-radical parameters, although this agent significantly reduced blood thromboxane levels. 4. Combined superoxide dismutase plus UK-38,485 treatment was not significantly better than either treatment alone with respect to any parameter. 5. Partial ischaemia led to consistently higher levels of tissue free radicals and blood thromboxane than did total ischaemia. Thus partial ischaemia appears to result in greater free-radical damage than total ischaemia. 6. These results are consistent with the hypothesis that thromboxane acts as a mediator for free-radical damage in the ischaemic changes within the flap.

Topics: Animals; Free Radical Scavengers; Free Radicals; Imidazoles; Ischemia; Rabbits; Reperfusion Injury; Skin; Surgical Flaps; Thromboxane A2; Thromboxane B2; Thromboxane-A Synthase

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Cell Count; Blood Pressure; Cardiac Output; Heart Rate; Hemodynamics; Indomethacin; Liver Transplantation; Reperfusion Injury; Swine; Syndrome; Thromboxane B2

We investigated if cyclooxygenase metabolites of arachidonic acid were involved in ischemia-reperfusion lung injury by determining if inhibition of their production attenuated the injury. Isolated rat lungs were perfused with physiologic salt solution osmotically stabilized with Ficoll until circulating blood elements were not detected in lung effluent. Ischemia was induced by stopping ventilation and perfusion for 90 min. Lung ventilation and perfusion were then resumed. Ischemia-reperfusion resulted in the production of prostacyclin and thromboxane assessed by lung effluent and tissue measurements of their respective stable metabolites, 6-keto-PGF1 alpha thromboxane B2 (TxB2). In contrast, prostaglandin F2 alpha did not increase. Ischemia-reperfusion also caused lung injury as assessed by increased lung 125I-BSA accumulation compared with nonischemic control lungs. Addition of the cyclooxygenase inhibitors, indomethacin, or flubiprofen to the lung perfusate before and after ischemia inhibited lung injury as well as the production of 6-keto-PGF1 alpha and TxB2. Addition of a thromboxane synthetase inhibitor (U 63557A) reduced lung injury as well as TxB2 formation without affecting the production of 6-keto-PGF1 alpha. The attenuation of lung injury was not explained by direct H2O2 removal by indomethacin, flubiprofen, or U 63557A because the concentrations of the inhibitors used in the isolated lung experiments did not remove exogenously added H2O2 from buffer in vitro. We conclude that cyclooxygenase metabolites of arachidonic acid are involved in ischemia-reperfusion injury to isolated rat lungs.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Benzofurans; Blood Pressure; Cyclooxygenase Inhibitors; Dinoprost; Flurbiprofen; Hydrogen Peroxide; Indomethacin; Lung; Male; Prostaglandin-Endoperoxide Synthases; Pulmonary Artery; Rats; Rats, Inbred Strains; Reperfusion Injury; Thromboxane B2; Thromboxane-A Synthase

Although the specific cause(s) of inflammatory bowel diseases (IBD) has not been identified, one theory suggests ischemia as the early event that occurs in IBD and reperfusion causes sustained release of oxyradicals, leading to inflammation and ulceration. In this study, we have confirmed that H2O2 in the concentration seen during ischemia/reperfusion is primarily responsible for cellular membrane damage in the rat colonic fragments in vitro. Hydrogen peroxide caused a time and dose-dependent increase in 6-keto-PGF1 alpha and TXB2 release. Hydrogen peroxide-stimulated 6-keto-PGF1 alpha release was blocked (50%) by phospholipase A2 (PLA2) inhibitors quinacrine and dimethyleicosadienoic acid at 5 min. Hydrogen peroxide-stimulated 6-keto-PGF1 alpha release was completely blocked by indomethacin, significantly blocked (69%) by nordihydroguiaretic acid, and completely blocked by catalase. Superoxide dismutase and uric acid failed to inhibit H2O2-stimulated 6-keto-PGF1 alpha release. Endogenous catalase inhibitors 3-aminotriazole and sodium azide further enhanced the release of 6-keto-PGF1 alpha stimulated by H2O2 by 29% and 73%, respectively. Xanthine-xanthine oxidase also increased 6-keto-PGF1 alpha release from the fragments by 110%. This release was not inhibited by superoxide dismutase and uric acid, but was completely inhibited by catalase. These studies suggest a direct effect of H2O2 on colonic fragments leading to submicroscopic cellular membrane damage and excess prostanoid production utilizing a PLA2/cyclooxygenase and catalase-sensitive pathway without the formation of toxic hydroxyl ions. The quick release of 6-keto-PGF1 alpha also suggests an early manifestation of H2O2-induced damage in rat colonic fragments.

Topics: 6-Ketoprostaglandin F1 alpha; Adrenal Cortex Hormones; Animals; Antioxidants; Calcimycin; Colon; Epithelium; Hydrogen Peroxide; Indomethacin; Intestinal Mucosa; Male; Organ Culture Techniques; Oxidation-Reduction; Phospholipases A; Phospholipases A2; Rats; Rats, Inbred Strains; Reperfusion Injury; Thromboxane B2; Uric Acid

Topics: Animals; Cold Temperature; Free Radicals; Hypertonic Solutions; Male; Organ Preservation; Pancreas Transplantation; Prostaglandins; Rats; Rats, Inbred Lew; Reperfusion Injury; Superoxide Dismutase; Thromboxane B2; Time Factors; Transplantation, Isogeneic

The correlation between protective effect of ginsenosides Rb + R0 and brain endogenously-derived prostacyclin synthesis, thromboxane A2 formation and lipid peroxidation were estimated in rats. Ginsenosides Rb + R0 100 mg/kg iv 30 min before 4-vessel occlusion elevated 6-keto-PGF1 alpha level, declined thromboxane B2 and brain edema formation, reduced the rise of lipid peroxides and suppressed the reduction in both creatine phosphokinase (CK) and superoxide dismutase (SOD) activities in brain tissue after 40-min ischemia followed by 1-h reperfusion. Furthermore, these improvements were partially abolished by pretreating with iv indomethacin. It is concluded that ginsenosides possess protective effect on cerebral ischemia-reperfusion injury of rats and ginsenosides Rb + R0 are the active principles. The underlying mechanism of protection is ascribed partially or mainly to the facilitated synthesis and release of prostacyclin, reduced formation of thromboxane A2 and inhibited generation of free radicals and subsequent lipid peroxidation.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Creatine Kinase; Female; Ginsenosides; Ischemic Attack, Transient; Lipid Peroxidation; Male; Malondialdehyde; Panax; Plants, Medicinal; Rats; Rats, Inbred Strains; Reperfusion Injury; Saponins; Superoxide Dismutase; Thromboxane B2

Topics: Animals; Arachidonic Acids; Cold Temperature; Hypertonic Solutions; Organ Preservation; Pancreas; Pancreas Transplantation; Rats; Rats, Inbred Lew; Reperfusion Injury; Thromboxane B2

This study tests the role of white blood cells (WBC) and leukotrienes in mediating the increased microvascular permeability following ischemia and reperfusion. Anesthetized dogs (n = 23) underwent 2 hours of hind limb ischemia induced by tourniquet inflation to 300 mmHg. In untreated animals (n = 7), tourniquet release led after 5 minutes to a rise in plasma thromboxane (Tx) B2 levels from 360 to 1702 pg/ml (p less than 0.05); after 2 hours, lymph TxB2 concentration had risen from 412 to 1598 pg/ml (p less than 0.05). There were decreases in circulating WBC from 11,766 to 6550/mm3 and platelets from 230 to 155 x 10(3)/mm3. During reperfusion, popliteal lymph flow (QL) increased from 0.07 to 0.24 ml/hour (p less than 0.05), while the lymph/plasma (L/P) protein ratio was unchanged from 0.39, changes consistent with increased microvascular permeability. WBC depletion (n = 7) to 302/mm3 by hydroxyurea or nitrogen mustard attentuated (p less than 0.05) the reperfusion induced rise in plasma TxB2 from 91 to 248 pg/ml and prevented the increase in lymph TxB2 concentration. Within 5 minutes of tourniquet release WBC counts further decreased to 191/mm3 (p less than 0.05) and platelets declined from 175 to 93 x 10(3)/mm3 (p less than 0.05). QL increased from 0.07 to 0.12 ml/hour (p less than 0.05), lower than untreated animals (p less than 0.05), and the L/P protein ratio declined from 0.49 to 0.37 (p less than 0.05), dilutional changes consistent with increased filtration pressure but not permeability to protein. Pretreatment with the lipoxygenase inhibitor diethylcarbamazine (DEC) (n = 8) prevented the reperfusion-induced increase in plasma and lymph TxB2 levels (p less than 0.05) and the fall in WBC counts (p less than 0.05), while platelet counts declined from 381 to 210 x 10(3)/mm3 (p less than 0.05). QL rose from 0.09 to 0.23 ml/hour (p less than 0.05) during reperfusion, and the L/P protein ratio of 0.3 remained unchanged, a value lower than in untreated dogs (p less than 0.05). In two animals of each group, vascular recruitment was induced by tourniquet inflation to 50 mmHg. This led to a high QL of 0.25 ml/hour and a low L/P ratio of 0.18. In untreated animals during reperfusion, QL further increased to 1.3 ml/hour, and L/P ratio rose to 0.44, documenting increased vascular permeability. In contrast, reperfusion in leukopenic or diethylcarbamazine (DEC)-treated dogs with vascular recruitment, was not associated with increases in QL or the L/P protein ratio

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Capillary Permeability; Diethylcarbamazine; Dogs; Hindlimb; Ischemia; Leukocyte Count; Leukocytes; Leukotrienes; Lymph; Platelet Count; Reperfusion Injury; Thromboxane B2

Lower torso ischemia leads on reperfusion to sequestration of polymorphonuclear leukocytes (PMN) in the lungs and increased permeability. This study tests the role of circulating leukocytes (WBC) in mediating this lung injury. Anesthetized sheep prepared with chronic lung lymph fistulae underwent 2 hours of bilateral hind limb tourniquet ischemia. In untreated controls (n = 7), 1 minute after reperfusion there were transient increases in mean pulmonary arterial pressure (MPAP) from 13 to 38 mmHg (p less than 0.05) and pulmonary microvascular pressure (Pmv) from 7 to 18 mmHg (p less than 0.05), changes temporally related to a rise in plasma thromboxane (Tx) B2 levels from 211 to 735 pg/ml (p less than 0.05). Lung lymph TxB2 levels rose from 400 to 1005 pg/ml at 30 minutes (p less than 0.05), and remained elevated longer than plasma levels. Lung lymph flow (QL) rose from 4.3 to 8.3 ml/30 minutes (p less than 0.05) after 30 minutes of reperfusion and remained elevated for 2 hours. The lymph/plasma (L/P) protein ratio was unchanged from 0.6, while the lymph protein clearance increased from 2.6 to 4.6 ml/30 minutes (p less than 0.05), suggesting increased microvascular permeability. WBC counts decreased within the first hour of reperfusion from 6853 to 3796/mm3 (p less than 0.05), and lung histology after 2 hours showed proteinaceous exudates and leukosequestration of 62 PMN/10 high-powered fields (HPF), higher than the 22 PMN/10 HPF (p less than 0.05) in sham animals (n = 3). Recruitment of the pulmonary vasculature by left atrial balloon inflation (n = 3) resulted in a rise in MPAP to 20 mmHg. After 3 hours of balloon inflation, QL stabilized at 9.8 ml/15 minutes, and a pressure-independent L/P protein ratio of 0.3 was achieved. During reperfusion, QL increased further to 11.2 ml/15 minutes, the L/P ratio rose to 0.56 and the calculated osmotic reflection coefficient decreased from 0.70 to 0.44, documenting an increase in lung microvascular permeability. In contrast to these untreated ischemic controls, sheep (n = 7) rendered leukopenic with hydroxyurea or nitrogen mustard and having a total WBC count of 760/mm3 and PMN count of 150/mm3 did not manifest reperfusion-induced increases in MPAP, Pmv, QL, lymph protein clearance, or lung lymph. TxB2 level (p less than 0.05). Plasma TxB2 levels rose slightly at 30 minutes from 199 to 288 pg/ml (p less than 0.05). Lung histology was normal. These data indicate that WBC mediate the ischemia-induced increase in pulmo

Topics: Animals; Blood Pressure; Capillary Permeability; Female; Hindlimb; Ischemia; Leukocyte Count; Leukocytes; Lung; Lymph; Pulmonary Artery; Reperfusion Injury; Sheep; Thromboxane B2