thiobarbituric-acid and Ischemia

To evaluate the effects of hypertonic saline solution associated to remote ischemic perconditioning in renal ischemia/reperfusion injury in rats.. Twenty five male rats (Wistar) underwent right nephrectomy and were distributed into five groups: Sham group (S); Ischemia/Reperfusion group (I/R) with 30 minutes of renal ischemia; Remote ischemic perconditioning group (Per) with three cycles of 10 minutes of I/R performed during kidney ischemia; Hypertonic saline solution group (HSS) treated with hypertonic saline solution (4ml/kg); remote ischemic perconditioning + Hypertonic saline solution group (Per+HSS) with both treatments. After reperfusion, blood samples were collected for BUN and creatinine serum levels analyzes. TBARS were evaluated in plasma and renal tissue to assess oxidative stress. Kidney histopathological examination were performed.. Per+HSS group showed a lower degree of renal dysfunction in relation to I/R group, whereas the technique of remote ischemic perconditioning isolated or associated with saline solution significantly reduced oxidative stress and histological damage.. Remote ischemic perconditioning associated or not to saline solution promoted reduction of acute renal injury induced by ischemia/reperfusion.

Topics: Animals; Blood Urea Nitrogen; Creatinine; Ischemia; Ischemic Preconditioning; Kidney; Kidney Function Tests; Male; Necrosis; Oxidative Stress; Protective Agents; Random Allocation; Rats, Wistar; Reperfusion Injury; Reproducibility of Results; Saline Solution, Hypertonic; Thiobarbiturates; Time Factors; Treatment Outcome

The aim of this study was to investigate any possible protective effect of ketamine in acute muscular ischaemia and reperfusion injury by measuring malondialdehyde using thiobarbituric acid assay in rats.. Twelve female Wistar albino rats were anaesthetized with chloral hydrate and randomly assigned into two groups to receive ketamine 1 mg kg(-1) min(-1) or saline infusion. Blood and gastrocnemius muscle samples were obtained 10 min after onset of infusion, before ischaemia. Then, femoral arteries were clamped for 30 min. Blood and muscle samples were obtained at the 30th minute of ischaemia and 10 min after reperfusion.. Muscle malondialdehyde concentrations were 27.88 +/- 2.45, 27.62 +/- 3.98 before ischaemia, 32.10 +/- 4.19, 30.77 +/- 2.73 in the 30th minute of ischaemia and 44.34 +/- 2.45, 34.83 +/- 2.78 after reperfusion in saline and ketamine-treated rats, respectively (nmol g(-1), mean +/- SD). The muscle malondialdehyde level after reperfusion was lower in ketamine-treated rats compared to saline group (P < 0.002). Plasma malondialdehyde levels were 3.77 +/- 0.16, 3.78 +/- 0.18 before ischaemia, 3.81 +/- 0.25, 4.00 +/- 0.86 at the 30th minute of ischaemia and 4.00 +/- 0.53, 3.94 +/- 0.95 after reperfusion, respectively, in saline and ketamine-treated rats (micromol L(-1), mean +/- SD). The effect of ketamine on muscular malondialdehyde was not observed in concurrent plasma malondialdehyde levels.. Ketamine was found to attenuate acute ischaemia-reperfusion injury in muscle tissue in rats (muscular protective). Ketamine may attenuate lipid peroxidation in muscle tissue in tourniquet-requiring manoeuvres.

Topics: Anesthetics, Dissociative; Animals; Female; Ischemia; Ketamine; Lipid Peroxidation; Lipid Peroxides; Malondialdehyde; Muscle, Skeletal; Protective Agents; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Sodium Chloride; Thiobarbiturates; Time Factors

The aim of this study was to investigate the extent to which ischemia and reperfusion lead to oxidative damage of the retinal tissue and investigate how ischemic and reperfused retinal tissues react to the application of perfluorooctylbromide (PFOB) and, if this reaction can be influenced by protective drugs such as vitamin E (Vit.E). The experiments were performed with 60 male Wistar rats, divided into 12 groups using an established model of reversible ischemia and reperfusion of the globe. Grouping of animals was carried out according to different ischemia and reperfusion periods and different therapeutic regimens (PFOB, Vit.E). Treatment with PFOB and/or Vit.E was performed after 60 min of ischemia with 60 min of reperfusion. At the end of the experiments thiobarbituric acid reactive substances (TBARS) were determined in the retinal tissues and served as parameters of oxidative tissue damage. Ischemia of up to 60 min led to a significant increase in TBARS values. Ninety and 120 min of ischemia led to no further significant elevation compared to the 60 min or 90 min group. Following 60 min of ischemia, a reperfusion period of 15 min led to an increase in TBARS values that was significant (P<0.05) after 30 and 60 min. Addition of PFOB resulted in a further significant (P<0.05) increase in TBARS values as compared to the respective group without treatment. Vit. E alone did not change the values significantly compared to the respective group without treatment. However, the application of Vit.E in addition to PFOB led to a significant reduction in TBARS values. Ischemia resulted in severe oxidative retinal tissue damage, which increased during reperfusion. The reperfusion damage might be due to the known depletion of protecting substances such as vitamin E. Enhancement of oxygen supply by PFOB during reperfusion without any tissue protection leads to more severe damage. Thus, additional protection of the tissue by powerful antioxidants is necessary when providing oxygen for better tissue recovery.

Topics: Animals; Fluorocarbons; Hydrocarbons, Brominated; Ischemia; Male; Peroxides; Rats; Rats, Wistar; Reperfusion Injury; Retina; Retinal Diseases; Thiobarbiturates; Time Factors; Vitamin E

Serum concentration of thiobarbituric acid (TBA) reactants in the hepatic vein were measured before and after transient dearterialization of the liver in five human subjects bearing unresectable hepatocellular carcinoma (HCC). During 1 hour of the occlusion of the hepatic artery, change in TBA reactants level was slight. However, the mean value of TBA reactants in 1 hour after the reflow increased to 1.50 +/- 0.11 nmol/ml (mean +/- S.E.) and was significantly higher (p < 0.05) than those before hepatic dearterialization (1.28 +/- 0.11 nmol/ml) and just before the release of occlusion (1.32 +/- 0.09 nmol/ml). Further, two endogeneous scavenger enzymes, superoxide dismutase (SOD) and catalase (CAT), and one of the major sources of oxygen free radicals, xanthine oxidase (XOD) were measured in human untreated HCC and the corresponding adjacent liver tissue. The results demonstrated an increase in SOD in 81.8% (9/11) of HCC, and a decrease in CAT in 72.7% (8/11) of HCC when compared with the corresponding adjacent liver tissue. The mean value of SOD in HCC was significantly higher (66.8 +/- 6.5 vs 52.8 +/- 3.8 U/mg protein; p < 0.05), and that of CAT was significantly lower (22.6 +/- 2.4 vs 36.0 +/- 6.1 U/mg protein; p < 0.05) than those in liver tissue. All of nine HCC samples had a significantly lower activity of XOD (6.4 +/- 1.9 vs 20.3 +/- 3.4 pmol/minute/mg protein; p < 0.01) than the corresponding liver tissue. There was no obvious relation between the content of SOD and CAT in HCC, or in liver tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Carcinoma, Hepatocellular; Catalase; Female; Free Radicals; Humans; Ischemia; Liver; Liver Circulation; Liver Neoplasms; Male; Middle Aged; Oxygen; Reactive Oxygen Species; Reperfusion; Superoxide Dismutase; Thiobarbiturates; Xanthine Oxidase

The effect of 4 hours of ischemia followed by reperfusion for 1 hour has been studied in fully anesthetized rabbits. Muscles from the limb subjected to ischemia and reperfusion showed considerable ultrastructural damage, although the distribution of damage between muscles was not uniform (anterior tibialis > soleus > quadriceps). Damage to the muscle was associated with a significant increase in the concentration of some indicators of free radical-mediated processes (thiobarbituric acid-reactive substances and diene conjugates), although others (glutathione and protein sulfhydryl groups) were unchanged. Reperfused muscles also showed considerable changes in their calcium and sodium contents. Treatment of animals with dantrolene sodium (4 mg/hr) throughout the periods of ischemia and reperfusion was found to preserve the ultrastructural appearance of quadriceps, soleus and anterior tibialis muscles. No effect of dantrolene sodium on indicators of free radical activity or muscle cation content was seen.

Topics: Animals; Cations; Dantrolene; Glutathione; In Vitro Techniques; Infusions, Intravenous; Ischemia; Microscopy, Electron; Muscle Relaxants, Central; Muscle, Skeletal; Myofibrils; Rabbits; Reperfusion Injury; Technetium; Thiobarbiturates

This study examined whether ischemia-reperfusion injury to skeletal muscle could be reduced by post-ischemic infusion of phosphoenolpyruvate (PEP) and adenosine triphosphate (ATP). The rectus femoris muscle of 54 rabbits was rendered ischemic for 3.5 hr. Eighteen rabbits received no further treatment. Thirty-six were infused intra-arterially at the end of ischemia, 18 with vehicle alone, and 18 with a mixture of PEP (80 mumol/kg) and ATP (2.6 mumol/kg). Six rabbits from each group were explored after 24 hr reperfusion and the muscles assessed for viability (by nitro blue tetrazolium), ATP (by luciferin-luciferase chemiluminescence), malonyldialdehyde (MDA) (thiobarbituric acid method), and water content. The remaining muscles in each group were examined histologically after either 1 hr or 4 days of reperfusion. At 24 hr the viability of the PEP/ATP infused muscles (78.9 +/- 15.4 percent) was significantly greater than that of untreated (41.4 +/- 27.3 percent) or vehicle-infused groups (34.0 +/- 32.7 percent). ATP stores were significantly higher and MDA (indicative of free radical activity) and water content significantly lower in the PEP/ATP treated group. At 24 hr and 4 days, muscles infused with PEP/ATP showed less necrosis and fewer infiltrating neutrophils than the untreated groups. Studies with isolated rabbit neutrophils showed that ATP alone significantly inhibited superoxide anion production by stimulated neutrophils. However, when combined with PEP at concentrations similar to those achieved in vivo, ATP did not significantly affect superoxide production. The findings indicate that post-ischemic infusion of PEP/ATP significantly reduces ischemia-reperfusion injury in rabbit skeletal muscle. The protective effect of PEP/ATP is more likely to be due to supplementation of intracellular ATP stores than to the inhibition of superoxide production by infiltrating neutrophils.

Topics: Adenosine Triphosphate; Animals; Body Water; Free Radicals; Indicators and Reagents; Injections, Intra-Arterial; Ischemia; Luminescent Measurements; Malondialdehyde; Muscle, Skeletal; Necrosis; Neutrophils; Nitroblue Tetrazolium; Pharmaceutical Vehicles; Phosphoenolpyruvate; Rabbits; Reperfusion Injury; Superoxides; Thiobarbiturates; Tissue Survival

When the rat kidney is subjected to ischemia and reperfusion, changes in glutathione content and in lipid peroxidation are produced in the cortex and in the medulla. The cortex shows a decrease in the glutathione content and a higher sensitivity to development of lipid peroxidation, the medulla being less affected. Reperfusion restores the glutathione concentration of the cortex during the first hours of reflow. The lipid peroxidation observed in the cortex and the medulla during reperfusion is higher than in ischemia. The protective role of glutathione and the response of the cortex and the medulla to ischemia-reperfusion injury are discussed.

Topics: Animals; Cerebral Cortex; Glutathione; Ischemia; Kidney Medulla; Lipid Peroxidation; Male; Oxidation-Reduction; Rats; Rats, Wistar; Reperfusion; Thiobarbiturates

This study was performed to evaluate the hypothesis that oxygen radicals/lipid peroxidation are involved in reperfusion injury in humans. The study included 37 patients, who underwent surgical revascularization operations for kidney transplantation (9 subjects) or limb salvage (28 subjects). Peripheral venous blood samples were taken 30 min before starting reperfusion (baseline) and 1, 2, 3, 4, and occasionally 6 to 18 h after revascularization. The amount of plasma malonaldehyde formed in the reaction with thiobarbituric acid (MDA-TBA) was determined by high-performance liquid chromatography (HPLC). The baseline MDA-TBA values of the patients were very close to the value determined for 20 age-matched healthy subjects (i.e. mean +/- SD 0.689 +/- 0.294 nmol/mL plasma [range 0.2 to 1.37] vs. 0.700 +/- 0.209 nmol/mL plasma [range 0.385 to 1.29]). All patients responded to successful revascularization with significant increase of the plasma MDA-TBA within about 1 h after onset of reperfusion. Thereafter the values decreased nearly to the preoperative state. The mean increase of MDA-TBA was 107% in kidney transplantation and 54% in limb revascularization. In a few patients with severe arteriosclerosis, revascularization was not optimal and no increase in the MDA-TBA value occurred. The results of this study indicate that therapeutic intervention to prevent lipid-peroxidation-mediated reperfusion injury is confined to a rather narrow time window and must be undertaken either prior to or immediately after revascularization.

Topics: Aged; Aged, 80 and over; Chromatography, High Pressure Liquid; Embolectomy; Extremities; Female; Humans; Ischemia; Kidney Transplantation; Kinetics; Lipid Peroxides; Male; Malondialdehyde; Middle Aged; Reperfusion; Thiobarbiturates; Thrombectomy

The influx of extracellular Ca2+ has been postulated to be one of the mediators of ischemia-reperfusion injury. A possible link between Ca2+ influx and oxygen radical generation has also been suggested. In the present study, using the isolated perfused rat liver, we evaluated the role of extracellular Ca2+ on oxygen radical generation, liver damage, and lipid peroxidation during 30 min ischemia and 60 min of reperfusion. Oxygen radical generation in the liver was continuously monitored by lucigenin-enhanced chemiluminescence. Liver damage and lipid peroxidation were evaluated by measuring lactate dehydrogenase (LDH) and thiobarbituric acid reactive substances (TBARS) release into the effusate, respectively. In the absence of extracellular Ca2+ (much less than 30 microM) oxygen radical generation from the liver increased gradually over 2 hr and there were concomitant increases in LDH and TBARS release. When livers were made ischemic and then reperfused, oxygen radical generation increased at the onset of reperfusion and then decreased over 30 min of reperfusion. After 30 min of reperfusion, livers reperfused with low Ca2+ buffer showed a linear increase in oxygen radical generation as well as progressive increases in LDH and TBARS release. On the other hand, livers reperfused with Ca2+ containing (1.25 mM) buffer showed no further increase in oxygen radical generation and no evidence of progressive liver damage and lipid peroxidation. These results suggest that Ca2+ overload is not a primary cause of liver ischemia-reperfusion injury and that the presence of extracellular Ca2+ during reperfusion is necessary to maintain normal liver function.

Topics: Acridines; Animals; Calcium; Free Radicals; Ischemia; L-Lactate Dehydrogenase; Liver; Oxygen; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thiobarbiturates

The placement of rubber band tourniquets upon rat hind-limbs for 5 h followed by reperfusion of the extremities results in a severe form of circulatory shock characterized by hypotension and death within 24 h of tourniquet release. Oxidative damage to muscle tissue is an early consequence of hind-limb reperfusion on tourniquet release, yet this local damage does not explain the lethal hypotensive shock state which evolves within the next 24 h. Multiple system organ failure (MSOF), of as of yet unknown causes, is usually described in relation to several shock states. It has been suggested that injured or necrotic tissue may activate neutrophils, platelets, and the coagulation system leading to embolization in remote tissues. Effective decreases in hepatic blood flow have been observed in several forms of sepsis which precedes the biochemical evidence consistent with an ischemic insult of the liver. In support of our original hypothesis, that organ failure has its genesis in a primary perfusion abnormality with secondary ischemic organ injury, herein we have assessed the possibility that oxygen-derived free radicals are generated in the liver of rats after reperfusion of their hind-limbs on release of the tourniquets. We report on the protective effects of allopurinol (ALLO) and a mixture of superoxide dismutase (SOD) catalase (CAT) and dimethylsulfoxide (DMSO) on liver free sulfhydryl content (SH), thiobarbituric acid-reactive substances (TBARS), and on the release of aspartic acid (AsT) and alanine aminotransferase (AlT) activities, and of alkaline phosphatase during a 5 h tourniquet period and after 2 h of reperfusion of the hind-limbs. During the hind-limb ischemic period hepatis tissue SH levels remained essentially constant during the first hour (6.02 +/- 0.36 to 5.65 +/- 0.20 mumoles/g wet tissue), and decreased significantly, over and above the normal circadian decrease of liver glutathione levels, to 4.02 +/- 0.69 mumoles/g wet tissue after the third hour and remained lowered until tourniquet release. A further significant decrease (3.11 +/- 0.49 mumoles/g wet tissue) was observed after 2h of reperfusion. TBARS production remained constant during the 5 h hind-limb ischemic period (168.4 +/- 37.3 mumoles/g wet tissue) and rose by 55% to 261.7 +/- 55.8 mumoles/g wet tissue after 2 h of tourniquet release. ALLO, but not the SOD-CAT-DMSO combination, protected hepatic SH loss during the hind-limb ischemic insult, yet both offered protection after 2 h o

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Aspartate Aminotransferases; Female; Free Radicals; Hindlimb; Ischemia; Liver; Liver Diseases; Male; Oxygen; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Shock; Sulfhydryl Compounds; Thiobarbiturates; Tourniquets

Low-pressure, hypothermic perfusion of isolated rabbit hearts for 24 hours compromises contractile function. This occurs despite continuous recirculation of an oxygenated solution. This investigation tested the hypothesis that such functional impairment results from irreversible tissue damage consequent to ischemia-induced lipid peroxidation. Decreases in coronary flow were measured during preservation and related to concentrations of thiobarbituric acid reactive species (TBA+, primarily malondialdehyde, a by-product of lipid peroxidation) in the tissue after preservation. The concentration of TBA+ species and the percent decrease in coronary flow rates at 30 minutes and 24 hours were positively correlated (r = 0.591 and r = 0.646, respectively). India ink was used as a marker of microvascular perfusion. Hearts showing the greatest magnitude of ischemia (evidenced by decreased percentages of perfused microvessels) had the highest levels of TBA+ species (r = 0.924). Moreover, hearts that had the highest levels of TBA+ species in the tissue exhibited the lowest levels of left ventricular function (as measured on a modified Langendorff apparatus; r = 0.767). We conclude that impaired coronary flow rates during perfused preservation portend compromised myocardial contractility. Furthermore, these changes occur largely within the first 30 minutes of perfusion. It is likely that early decrements in microvascular perfusion and consequent tissue injury owing to lipid peroxidation underlie impaired myocardial function after preservation.

Topics: Animals; Blood Flow Velocity; Coronary Circulation; Hypothermia, Induced; In Vitro Techniques; Ischemia; Lipid Peroxidation; Myocardial Contraction; Myocardium; Organ Preservation; Perfusion; Pressure; Rabbits; Thiobarbiturates; Time Factors; Ventricular Function, Left

Using the isolated perfused rat liver, we investigated the relationship of glutathione (GSH) with reactive oxygen species (ROS) generation and liver cell damage during ischemia/reperfusion in normal and GSH-depleted conditions. Lucigenin-enhanced chemiluminescence was used as a sensitive index of tissue ROS generation. After 30 minutes of equilibration, livers were subjected to global ischemia for various times (60 or 90 minutes) and then reperfused for another 120 minutes. Intracellular ROS levels increased sharply at the onset of reperfusion and then declined slowly. After 30 to 60 minutes of reperfusion, ROS levels started to increase progressively in a linear fashion. However, sinusoidal glutathione disulfide release did not increase during reperfusion in the same livers, suggesting that intracellular ROS generation is too low to cause a significant increase in GSH oxidation. Pretreatment with phorone (300 mg/kg intrapentoneally [ip]), which reduced hepatic GSH by 90%, did not cause any difference in intracellular ROS generation compared with the control livers. There were also no significant differences in lactate dehydrogenase and thiobarbituric acid reactive substances (TBARS) release between the control and phorone-treated livers during reperfusion after various times of ischemia. These data indicate that ROS generation in the normal isolated perfused liver during ischemia/reperfusion is extremely low and intracellular GSH does not serve as a major intracellular defense system against such a low oxidative stress.

Topics: Acridines; Animals; Glutathione; Ischemia; Ketones; Kinetics; L-Lactate Dehydrogenase; Lipid Peroxidation; Liver; Luminescent Measurements; Male; Oxidation-Reduction; Oxygen; Rats; Rats, Inbred Strains; Reperfusion Injury; Thiobarbiturates

In the present study, we quantified the biochemical [thiobarbituric acid (TBA) reactants, superoxide dismutase (SOD) and vitamin E] and histologic changes in the small intestinal tissue after ischemia and/or reperfusion. Sixty-seven Wistar rats were divided into 7 groups; N group: control, A-I group: 30 min. ischemia, A-II group: 120 min. ischemia, B-I group: Declamp after 30 min. ischemia, B-II group: 30 min. reperfusion after 30 min. ischemia, B-III group: 30 min. reperfusion after 120 min. ischemia, E group: vitamin E administration 30 min. reperfusion after 30 min. ischemia. The levels of TBA reactants were significantly different between A-II and B-II, B-II and E (all p less than 0.01). For SOD, there were significant differences between N and B-I (p less than 0.01), N and E (p less than 0.05). For vitamin E, there were significant differences between A-I and B-I, A-I and B-I, B-II and E (all p less than 0.01). Histologic changes showed that the grade of tissue injury was more severe in B-I and B-II than in A-I, and was less in E than in B-II. It is suggested that vitamin E protected cells from injury due to oxygen free radicals.

Topics: Animals; Free Radicals; Intestine, Small; Ischemia; Lipid Peroxides; Male; Oxygen; Rats; Rats, Inbred Strains; Reperfusion Injury; Superoxide Dismutase; Thiobarbiturates; Vitamin E

Ischemia induced oxygen free radical damage was formerly attributed only to xanthine oxidase in intestine, liver, kidney and heart. A reevaluation indicated neutrophils as one of the major sources of postischemic oxidative tissue damage, chiefly in the intestine. Our data, obtained from the same occlusion time period for intestine, liver and kidney, showed a certain oxidative damage in intestine and kidney already during ischemia, expressed by an increase of thiobarbituric acid reactive substances (TBARS), whereas the liver sustained damage of this kind only during reperfusion. Oxidative stress was expressed by a comparison of the increase of TBARS, though this test is not a measure of a specific product of lipid peroxidation, but rather comprises several breakdown products of free radical damage. Myeloperoxidase as measure of neutrophil stimulation increased in the intestine and liver. The kidney sustained damage without an increase of myeloperoxidase activity, but showed a similar pattern of increase of TBARS as in the intestine. Our data suggest a major role of neutrophils in intestinal ischemia induced damage, where neutrophils can effect initiation and propagation. In the liver neutrophils may play a minor role concerning propagation, but they may act as an important initiating mechanism. Hepatic tissue shows a high ischemic tolerance, which is demonstrated by a missing increase of TBARS in spite of a certain increase of myeloperoxidase activity during ischemia. This can be interpreted by the high capacity of antioxidative mechanisms of liver tissue and the ability of a higher oxygen extraction ratio under nearly ischemic conditions. In the kidney there appears a smaller contribution of neutrophils. The similar pattern of increase of TBARS in kidney and intestine demonstrates a comparable low ischemic tolerance of these two tissues, whereas different initiating and propagating systems may occur.

Topics: Animals; Aorta; Arterial Occlusive Diseases; Intestinal Mucosa; Intestines; Ischemia; Kidney; Lipid Peroxidation; Liver; Male; Peroxidase; Rats; Rats, Inbred Strains; Reperfusion; Thiobarbiturates

Reperfusion of rat kidney submitted to temporal ischaemia induces a decrease in glutathione content. Lipid peroxidation is not detected in kidney homogenates but microsomes obtained after periods of reperfusion longer than 60 minutes show increased malondialdehyde values correlated with high oxygen consumption and superoxide free radical generation. Microsomes obtained from kidneys submitted to 15 or 60 minutes of reperfusion are resistant to NADPH-induced lipid peroxidation but after 120 minutes of reperfusion an increased lipid peroxidative response is observed. Although the mechanism of the protection found in microsomes against the induction of oxidative stress in the first 60 minutes of reperfusion is unknown, it is postulated that this subcellular fraction plays an important role in the oxidative stress observed after longer periods of reperfusion.

Topics: Animals; Free Radicals; Glutathione; Ischemia; Kidney; Kinetics; Lipid Peroxidation; Male; Microsomes; NADP; Oxidation-Reduction; Oxygen; Rats; Rats, Inbred Strains; Reperfusion Injury; Superoxides; Thiobarbiturates

Reactive oxygen species are a major cause of damage occurring in ischemic tissue after reperfusion. During reperfusion transitional metals such as iron are required for reactive oxygen species to mediate their major toxic effects. Xanthine oxidase is an important source of reactive oxygen species during ischemia-reperfusion injury, but not in all organs or species. Because cytochrome P-450 enzymes are an important pulmonary source of superoxide anion (O2-.) generation under basal conditions and during hyperoxia, and provide iron catalysts necessary for hydroxyl radical (.OH) formation and propagation of lipid peroxidation, we postulated that cytochrome P-450 might have a potential role in mediating ischemia-reperfusion injury. In this report, we explored the role of cytochrome P-450 enzymes in a rabbit model of reperfusion lung injury. The P-450 inhibitors 8-methoxypsoralen, piperonyl butoxide, and cimetidine markedly decreased lung edema from transvascular fluid flux. Cimetidine prevented the reperfusion-related increase in lung microvascular permeability, as measured by movement of 125I-albumin from the vascular space into lung water and alveolar fluid. P-450 inhibitors also prevented the increase in lung tissue levels of thiobarbituric acid reactive products in the model. P-450 inhibitors did not block enhanced O2-. generation by ischemic reperfused lungs, measured by in vivo reduction of succinylated ferricytochrome c in lung perfusate, but did prevent the increase in non-protein-bound low molecular weight chelates of iron after reperfusion. Thus, cytochrome P-450 enzymes are not likely a major source of enhanced O2-. generation, but serve as an important source of iron in mediating oxidant injury to the rabbit lung during reperfusion. These results suggest an important role of cytochrome P-450 in reperfusion injury to the lung and suggest potential new therapies for the disorder.

Topics: Animals; Capillary Permeability; Cimetidine; Cytochrome P-450 Enzyme System; Iron; Ischemia; Lung; Methoxsalen; Piperonyl Butoxide; Rabbits; Reperfusion Injury; Superoxides; Thiobarbiturates

In this study we have examined the effect of propionyl-L-carnitine (PC) on rat spinal cord ischaemia and post-ischaemic reperfusion injury by evaluating two lipid peroxidation indices, thiobarbituric acid reactive substances (TBARS) and diene conjugation, before and after the addition of an ADP-Fe+2 complex to spinal cord homogenates. Aerobic, ischaemic, and post ischaemic reperfusion rat spinal cord homogenates from PC treated and untreated animals did not show any statistically significant difference in their TBARS and conjugated diene content. The addition of the ADP-Fe+2 complex to these homogenates resulted in an increased production of both the lipid peroxidation indices, though the magnitude of such formation was related to the type of experimental intervention. The post-ischaemic reperfusion samples of untreated rats showed the highest TBARS and conjugated diene content, while ischaemic samples in either treated and untreated rats did not show any statistically significant difference with respect to the aerobic samples. The post-ischaemic reperfusion samples of treated rats showed a statistically significant decrease of TBARS and conjugated diene production in comparison to the untreated samples. In addition, PC was also able to partially inhibit TBARS and conjugated diene formation in linoleic acid micelles exposed to hemoglobin, though it did not protect albumin fragmentation from the irradiation of water with an X-ray source.

Topics: Animals; Carnitine; Free Radicals; In Vitro Techniques; Ischemia; Lipid Peroxidation; Male; Rats; Rats, Inbred Strains; Reperfusion Injury; Spinal Cord; Thiobarbiturates

The influences of vitamin E deficiency on compression injury of the rat spinal cord associated with ischemia were investigated. Growing rats were divided into two groups and given a diet containing either 2 IU/100 g or less than 0.1 IU/100 g of alpha-tocopherol acetate, respectively, for 6-8 weeks before experiments. Motor disturbances induced by spinal cord injury were found to be enhanced by vitamin E deficiency. The spinal cord blood flow (SCBF) was reduced by compression and subsequently increased transiently and then decreased gradually in both groups, but the level was lower in the vitamin E-deficient group than in the control group. After injury, the vitamin E-deficient group showed lower recoveries than the control group in the amplitude and latency of spinal cord evoked potentials and greater pathological changes of the spinal cord, such as bleeding and edema. The increase in the level of TBA-reactive substances in the spinal cord after injury increased with decrease in the dietary level of vitamin E. These results suggest that vitamin E may have a protective effects against ischemic spinal cord injury by its antioxidant effect.

Topics: Animals; Blood Circulation; Evoked Potentials; Ischemia; Lipid Peroxidation; Lipid Peroxides; Male; Rats; Rats, Inbred Strains; Spinal Cord Compression; Thiobarbiturates; Vitamin E; Vitamin E Deficiency

The role of superoxide and lipid peroxidation in liver injury induced by ischemia-reperfusion was investigated in rats. Ischemic condition of the liver was created by applying small clamps to the right branch of portal vein and the right hepatic artery for 15 min. Clamping of hepatic artery and portal vein could decrease the hepatic blood flow to about 30% of that measured before the clamping. Levels of serum GPT and thiobarbituric acid (TBA) reactive substances in the liver tissue were significantly increased 30 min after the reperfusion following 15 min of ischemia. The increase in serum GPT and TBA reactants in the liver tissue was significantly inhibited by the treatment with superoxide dismutase combined with catalase. The treatment with allopurinol significantly inhibited the elevation of serum GPT levels and showed a tendency to inhibit the increase in TBA reactants in liver tissue. These results suggest that active oxygen species and lipid peroxidation may play an important role in the pathogenesis of ischemia-reperfusion injury in the liver, and hypoxanthine-xanthine oxidase system may be one of the main sources of active oxygen species.

Topics: Animals; Catalase; Ischemia; Lipid Peroxidation; Liver; Liver Circulation; Male; Oxygen; Rats; Rats, Inbred Strains; Reperfusion; Superoxide Dismutase; Thiobarbiturates

The author of this report has studied peroxide lipid and evoked potentials of the spinal cord during ischemia and after reperfusion. In addition, he has studied effects of vitamin E (V.E.) upon ischemic spinal cord. The ischemia of the spinal cord was experimentally produced by clamping the thoracic aorta of Wistar rats and subsequently removing the clamps. Wistar rats were given diet containing 2 IU/100 g (control group) or 50 IU/100 g (V.E. group) of alpha-tocopherol acetate for 6 weeks before experiments. In the V.E. group the quantity of thiobarbituric acid reactive substance (TBARS) in the spinal cord after clamp removal was lower than the control group. The V.E. content in the spinal cord indicated a negative correlation to the TBARS values. The evoked spinal potentials in both groups disappeared due to spinal cord ischemia. The control group displayed wave form loss earlier than the V.E. group. It is conceivable that lipid peroxidation correlate to the tissue damage following spinal cord ischemia and reperfusion, and V.E. has the preventive effect to the damage.

Topics: Animals; Evoked Potentials; Ischemia; Lipid Peroxides; Rats; Rats, Inbred Strains; Reaction Time; Spinal Cord; Thiobarbiturates; Vitamin E

Earlier studies from our laboratory have shown that hyperbaric oxygen (HBO) treatment reduces edema, enhances aerobic metabolism and improves the recovery of the phosphorylase activity in postischemic rat skeletal muscle. However, as it has become increasingly apparent that oxygen in excess may have harmful effects, it was of interest to study if HBO caused an increased formation of oxygen free radicals. Toxic peroxides, as a result of oxygen free radicals, were quantitated in the postischemic skeletal muscle of rat and with HBO treatment by measuring the thiobarbituric acid reaction which includes the lipid peroxides and the alkydes including malondialdehyde (MDA), a key intermediate in the formation of peroxides. A tourniquet model of temporary ischemia of the rat hindlimb was used for 3 hours. Muscle biopsies were taken at various intervals before and after tourniquet release with and without hyperbaric oxygen at 2.5 atmospheres absolute (ATA) for 45 min after tourniquet release. Three hours of anesthesia caused a significant rise of thiobarbituric acid reactive material (TBAR) concentration in muscle compared to normal controls without anesthesia. An increase of similar magnitude was seen after 3 hours of ischemia, with or without reperfusion. These values were normalized after 45 min. HBO in the postischemic phase did not cause a further increase in the TBAR concentration in muscle immediately postischemically. However, the levels remained increased at 45 min after the onset of reperfusion, immediately after HBO treatment and had returned to normal values 2 hours postischemically.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Free Radicals; Hindlimb; Hyperbaric Oxygenation; Ischemia; Lipid Peroxidation; Male; Muscles; Rats; Rats, Inbred Strains; Thiobarbiturates