bq-123 and Reperfusion-Injury

Topics: Animals; Endothelin Receptor Antagonists; Gastrointestinal Motility; Ileum; Male; Oligopeptides; Peptides, Cyclic; Piperidines; Rats; Rats, Wistar; Reperfusion Injury

The optimal vasodilator to avoid hepatic artery vasospasm during normothermic ex vivo liver perfusion (NEVLP) is yet to be determined. We compared safety and efficacy of BQ123 (endothelin1 antagonist), epoprostenol (prostacyclin analogue), and verapamil (calcium channel antagonist).. Livers from porcine heart beating donors were perfused for 3 hours and transplanted into recipient pigs. Four groups were compared: group 1, livers perfused with a dose of 1.25 mg of BQ123 at baseline and at 2 hours of perfusion; group 2, epoprostenol at a continuous infusion of 4 mg/h; group 3, verapamil 2.5 mg at baseline and at 2 hours of perfusion; group 4, no vasodilator used during ex vivo perfusion. Liver injury and function were assessed during perfusion, and daily posttransplantation until postoperative day (POD) 3. All groups were compared with a cold storage group for postoperative graft function.. Hepatic artery flow during NEVLP was significantly higher in BQ123 compared with verapamil, epoprostenol, and no vasodilator-treated livers. Aspartate aminotransferase levels were significantly lower with BQ123 and verapamil compared with epoprostenol and control group during perfusion. Peak aspartate aminotransferase levels were lower in pigs receiving BQ123 and verapamil perfused grafts compared with epoprostenol and control group. International Normalized Ratio, alkaline phosphatase, and total bilirubin levels were lower in the BQ123 and verapamil groups compared to epoprostenol group. Cold storage group had increased markers of ischemia reperfusion injury and slower graft function recovery compared to machine perfused grafts.. The use of BQ123, epoprostenol, and verapamil during NEVLP is safe. Livers perfused with BQ123 and verapamil have higher hepatic artery flow and reduced hepatocyte injury during perfusion compared with epoprostenol. Hepatic artery flow is significantly reduced in the absence of vasodilators during NEVLP.

Topics: Animals; Apoptosis; Calcium Channel Blockers; Endothelin Receptor Antagonists; Epoprostenol; Hepatic Artery; Liver; Liver Circulation; Liver Transplantation; Male; Necrosis; Peptides, Cyclic; Perfusion; Reperfusion Injury; Sus scrofa; Vasoconstriction; Vasodilator Agents; Verapamil

Testicular torsion is a well-known medical emergency that can lead to pathological changes in the testicular tissues and male infertility. This investigation was undertaken to gain insight into the effects of an endothelin type A receptor antagonist (BQ123) on torsion-induced germ cell loss. Twenty-eight male Wistar albino rats were divided into four groups. In group I (control group), a sham operation to the left testis was performed. In group II (I/R injury), I/R injury was created by rotating the left testis 720° in a clockwise direction for 2 h and detorsing the testis after 2 h. In group III (I/R injury+BQ123), the rats were subjected to I/R injury and BQ123 injection (1 mg/kg, intravenous). In group IV (control+BQ123), the sham operated rats were subjected to BQ123. The testes of the rats were removed in all groups. Torsion-induced apoptosis and the effects of BQ123 were examined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL) technique, immunohistochemistry and western blotting. In group II, the number of TUNEL-positive cells increased after testicular torsion. Immunohistochemistry and western blotting showed that apoptotic proteins (active caspase 3 and Bax) were upregulated, and the anti-apoptotic protein Bcl2 was downregulated in I/R injury. The administration of BQ123 caused a significant decrease in the number of apoptotic cells and the expression of apoptotic proteins (p<0.05) when compared with the I/R injury group. No significant effect of BQ123 was observed in the testicular cells of group IV. This animal study provides evidence of the regulatory effects of BQ123 on torsion-induced testicular apoptosis.

Topics: Animals; Apoptosis; Blotting, Western; Disease Models, Animal; Endothelin A Receptor Antagonists; Immunohistochemistry; In Situ Nick-End Labeling; Male; Peptides, Cyclic; Rats; Rats, Wistar; Reperfusion Injury; Spermatic Cord Torsion

Ischemia and subsequent reperfusion are known to impair renal function. We examined several agents that might prevent renal impairment or enhance the recovery of renal function after ischemia/reperfusion injury in rats. Different degrees of preventive effects were observed in rats treated with captopril, BQ-123 (endothelin type A receptor antagonist), sodium nitroprusside (SNP, a nitric oxide donor), and losartan (angiotensin II type 1 receptor antagonist). Only minimal changes in renal morphology were observed after treatment with losartan, SNP, captopril, and BQ-123 compared with control animals. On the other hand, lesions were prominent in the N(G)-nitro-L-arginine-methyl ester (L-NAME)- and L-arginine-treated rats. The Na(+)-K(+) ATPase activity of ischemic kidneys was, however, preserved in all treatment groups, except in those treated with L-arginine and L-NAME, which showed a marked reduction in Na(+)-K(+) ATPase activity. Our post-treatment data suggest that losartan and SNP have the greatest potential for therapeutic use to mitigate post-ischemic renal damage and functional impairment.

Topics: Adenosine Triphosphatases; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Arginine; Captopril; Ischemia; Kidney; Losartan; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide Donors; Nitroprusside; Peptides, Cyclic; Rats, Wistar; Renal Insufficiency; Reperfusion; Reperfusion Injury

Intestinal ischemia/reperfusion (I/R) injury remains associated with high morbidity and mortality. The protective efficacy of the following endothelin (ET) receptor blockers: BQ-123 (ET(A) receptor), BQ-788 (ET(B)); tezosentan (dual ET blocker) was tested against the inhibition of gastrointestinal (GI) motility induced by intestinal I/R. Intestinal Evans blue transit was measured in untreated (UN) rats and animals subjected to skin incision (SI), I/R (1h superior mesenteric artery clamping followed by 2-24h reperfusion) or sham operation (SO). Surgical procedures were conducted under diethyl ether anesthesia. Anesthesia and SI did not affect the GI transit compared to UN rats. In contrast both SO and I/R significantly reduced GI motility, the latter evident at 2-24h of reperfusion. Tezosentan (1-10 mg/kg), BQ-123 and BQ-788 (0.1-1 mg/kg) protected against I/R-induced inhibition of intestinal motility in a time- and dose-dependent manner at the early and late stages of reperfusion. Furthermore tezosentan alleviated the I/R-induced decrease in the contractile response of the longitudinal jejunal smooth muscle strips to carbachol in vitro. The serum ET(1-21) level was increased at 2h but not 24h of reperfusion compared to SO animals and ET(1-21) was higher in tezosentan pretreated rats.

Topics: Anesthesia, Inhalation; Anesthetics, Inhalation; Animals; Carbachol; Dose-Response Relationship, Drug; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin Receptor Antagonists; Endothelin-1; Ether; Evans Blue; Gastrointestinal Motility; Male; Muscarinic Agonists; Oligopeptides; Peptides, Cyclic; Piperidines; Pyridines; Rats; Rats, Wistar; Reperfusion Injury; Surgical Procedures, Operative; Tetrazoles

Endothelins (ET) can be considered stress-responsive regulators working in paracrine and autocrine fashion. It has been suggested that elevated levels of ET may be responsible for the low coronary re-flow phenomena. Ischemia-reperfusion (I/R) was shown to stimulate ET release in rat heart; however, the mechanism(s) of this effect has not been clarified. Therefore, this study was focused to investigate the effect of BQ-123, selective ETA receptor antagonist, on three aspects of myocardial ischemia-reperfusion (MI/R) injury: hemodynamic parameters, infarct size and oxidant-antioxidant status in the absence and presence of ET-1 in an vivo rat model.. To produce MI/R, a branch of the descending left coronary artery was occluded for 30 min followed by 2h reperfusion. ECG changes, blood pressure (BP), and heart rate (HR) were measured before occlusion and continued both occlusion and reperfusion. Forty rats were randomly assigned to five groups equally: (1) sham-operated rats without coronary ligation, (2) I/R group, (3) I/R+BQ-123-treated group (10 microg/kg/min i.v.), (4) I/R+ET-treated group (25 ng/kg/min i.v.), (5) I/R+ET+BQ-123-treated group. The results are expressed as mean+/-S.E.M. In the ET-1 plus I/R group, the ratio between the infarcted area and area at risk 56+/-1% was significantly higher than I/R group (49+/-1%). In the BQ-123 group with or without exogenous ET-1 treatment in I/R group, this ratio was significantly lower at 40+/-2 and 37+/-1%, respectively. As compared to sham group, I/R increased lipid peroxidation whereas decreased nitric oxide (NO), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) contents. This decreased antioxidant enzymatic defense could result in aggravated oxidative damage in I/R group rat hearts. ET-1 administration group showed severe oxidative damage. BQ-123 administrations to I/R group with or without ET-1 caused significantly decrease in lipid peroxidation and increased in SOD, CAT activities and NO generation and GSH content when compared with I/R group alone.. The most important finding of the present study is that the ET blockade reduced I/R-induced myocardial injury. The mechanism of this reduction was speculated to be a resistance to ischemic injury in the subcellular levels of the myocardium conferred by a reduction of vascular constriction and improvement of imbalance in the antioxidant status.

Topics: Animals; Blood Pressure; Endothelin A Receptor Antagonists; Heart Rate; Hemodynamics; Male; Malondialdehyde; Myocardial Infarction; Myocardium; Oxidants; Oxidative Stress; Peptides, Cyclic; Rats; Reperfusion Injury

Ischemia-reperfusion (I/R) injury induces an inflammatory response and production of oxygen-derived reactive species which affect many organs including heart, brain, kidney and gastrointestinal tract. The aim of this study was to assess the hepatic changes after renal I/R injury. Male Sprague Dawley rats were subjected to either sham operation or treatment with L-NAME, L-arginine and BQ-123 during 30 min renal ischemia and 2 h reperfusion injury. Hepatic superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) activities, and thiobarbituric acid-reactive substances (TBARS) and nitric oxide (NO) levels were evaluated to show hepatic response to renal I/R injury. Catalase and SOD activities showed significant differences between the control and the other groups after I/R. On the other hand, GSH-Px activity did not show any significant changes between the control and the other experimental groups mentioned under above conditions. Meanwhile, levels of TBARS were not different between the control and the other experimental groups, whereas NO level showed changes between the control and experimental groups except the one to which endothelin receptor antagonist agent (BQ-123) subjected. Experimental period may not be enough to determine the changes in GSH-Px activity and level of TBARS. However, catalase and SOD activities decreased in experimental groups treated by chemical agents. NO level decreased in chemicalagent-applied experimental groups but not in the group to which endothelin receptor antagonist BQ-123 was applied alone.

Topics: Animals; Antihypertensive Agents; Antioxidants; Enzyme Inhibitors; Glutathione Peroxidase; Kidney; Liver; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Peptides, Cyclic; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Superoxide Dismutase

The aim of this study was to investigate whether the protective effect of endothelin-A (ET(A)) receptor antagonist BQ-123 against renal ischemia reperfusion (I/R) injury is related to nitric oxide (NO) production. Sprague-Dawley rats were divided into six groups: control, I/R, N sup omega nitro-L-arginine methyl ester (L-NAME), BQ, BQ+L-NAME, BQ+L-NAME+L-Arg groups. After urethane anesthesia, 30min renal ischemia and 2h reperfusion were performed in all groups except control group. Mean arterial pressures (MAP) during reperfusion in all L-NAME-treated groups were higher than during pre-ischemia and ischemia, however, MAP at 60th and 120th minute of reperfusion in control and BQ groups were lower than during ischemia. MAP of L-NAME-treated groups were significantly higher than the other groups during reperfusion period. The I/R caused lipid peroxidation and protein oxidation, however, BQ-123 treatment prevented oxidant injury. The inhibition of NO production prevented effect of BQ-123 treatment. Also, BQ-123 treatment caused an increase in superoxide dismutase and catalase activities. Both BQ-123 and L-NAME treatments prevented high xanthine oxidase activity. BQ-123 prevented risen myeloperoxidase activity and L-NAME reversed this effect of BQ-123 just like the addition of L-arginine to the treatment altered the effect of L-NAME. The plasma BUN was affected as increasing manner from L-NAME treatments; on the other hand, plasma Cr and Na concentrations were affected as decreasing manner from BQ-123 treatments. ET(A) receptor antagonist BQ-123 may be revealed a protective agent against renal I/R injury with a possible secondary pathway via its antioxidant effects. We suggest that BQ-123 may mediate the protective effect via a NO-dependent mechanism.

Topics: Animals; Blood Pressure; Blood Urea Nitrogen; Catalase; Endothelin A Receptor Antagonists; Endothelin-1; Enzyme Inhibitors; Glutathione Peroxidase; Kidney; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Organ Size; Peptides, Cyclic; Peroxidase; Rats; Rats, Sprague-Dawley; Renal Circulation; Reperfusion Injury; Sodium; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Xanthine Oxidase

To analyse the coronary effects of endothelin-1 after ischemia-reperfusion, the left anterior descending coronary artery of anesthetized pigs was subjected to 30-min occlusion followed by 60-min reperfusion. Then, rings distal (ischemic arteries) and proximal (control arteries) to the occlusion were taken from this artery and prepared for isometric tension recording. The sensitivity of the contraction in response to endothelin-1 (3 x 10(-10)-3 x 10(-7) M) and the endothelin ET(B) receptor agonist IRL-1620 (3 x 10(-10)-3 x 10(-7) M) was greater in ischemic vessels. The endothelin ET(A) receptor antagonist BQ-123 (10(-7)-3 x 10(-6) M) decreased the sensitivity of the response to endothelin-1 similarly in ischemic and control arteries. The endothelin ET(B) receptor antagonist BQ-788 (10(-6) M), endothelium removal or the inhibitor of nitric oxide synthesis N(omega)-nitro-L-arginine methyl ester (L-NAME 10(-4) M) potentiated the response to endothelin-1 and IRL-1620 in control arteries only. The cyclooxygenase inhibitor meclofenamate (10(-5) M) augmented the maximal response to endothelin-1 in control arteries, and reduced it in ischemic arteries. In precontracted arteries, IRL-1620 (3 x 10(-11)-3 x 10(-10) M) relaxed control but not ischemic arteries, and L-NAME or meclofenamate abolished this relaxation. Therefore, ischemia-reperfusion increases the coronary vasoconstriction in response to endothelin-1 probably due to impairment of endothelin ET(B) receptor-induced release of nitric oxide and prostacyclin, augmentation of the contractile response to activation of endothelin ET(B) receptors, and increased release of vasoconstrictor prostanoids.

Topics: Animals; Arteries; Blood Pressure; Coronary Vessels; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Endothelins; Enzyme Inhibitors; Female; Heart Rate; In Vitro Techniques; Male; Meclofenamic Acid; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Nitroprusside; Oligopeptides; Peptide Fragments; Peptides, Cyclic; Piperidines; Prostaglandins; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; Reperfusion Injury; Swine; Vasoconstriction; Vasodilation; Vasodilator Agents

In this study, the effects of BQ123 (an ET(A) receptor antagonist), bosentan (a nonselective ET(A)-ET(B) antagonist), and phosphoramidon (an endothelin converting enzyme inhibitor) were investigated on intestinal mucosal lesion formation and changes in tissue PGE2 and LTC4 levels due to intestinal ischemia-reperfusion (I/R) injury in rats. Following 30 min of ischemia, the substances were given via the inferior caval vein, and 10 min later the intestine was subjected to reperfusion for 30 min. The intestinal specimens were evaluated both microscopically and the tissue PGE2 and LTC4 levels were obtained for each group. The histopathologic examination revealed a significant reduction in tissue injury in both BQ123 and phosphoramidon pretreated groups compared with the control group. Bosentan, on the contrary, did not decrease the injury. The pharmacologic examination revealed a significant reduction of PGE2-like activity in both BQ123 and phosphoramidon pretreated groups, compared with the control group, while LTC4-like activity remained unchanged except for an increase in the bosentan pretreated group.

Topics: Animals; Bosentan; Dinoprostone; Endothelin Receptor Antagonists; Endothelins; Female; Glycopeptides; Histocytochemistry; Intestinal Mucosa; Intestines; Ischemia; Leukotriene C4; Male; Peptides, Cyclic; Rats; Reperfusion Injury; Sulfonamides

We studied the effects of the specific endothelin (ETA) receptor antagonist, BQ-123, on reperfusion injury in a rat model of kidney transplantation. First, Sprague-Dawley rats were divided into three groups: a sham nephrectomy (SNEPH), an autotransplantation (AUTO-Tx), and an allotransplantation (ALLO-Tx) group. In a fourth group, ALLO-Tx + BQ, allografts were flushed with 20 micrograms BQ-123 containing cold Ringer's lactate before transplantation. For the allograft groups, kidneys from white Wistar albino rats were transplanted into allogeneic Sprague Dawley recipients. Grafts were allowed 120 min of reperfusion after 40 min of cold ischemia. ET-1,2 plasma concentrations in the renal venous blood, and kidney tissue prostaglandin (PG) E2 and leukotriene (LT) B4 levels were studied. Diene conjugates (DC), hydroxyalkanals (HAA), hydroxyalkenals (HAE) and malondialdehyde (MDA) levels, as the products of lipid peroxidation, and protein carbonyls (PC) and protein sulphydryls (PS), as the parameters of protein oxidation, were also analyzed in the kidney tissue. Plasma ET concentrations increased significantly in the AUTO-Tx and ALLO-Tx groups (P < 0.05 and P < 0.01, respectively) but this increase was reversed in the ALLO-Tx + BQ group. None of the lipid peroxidation products except DCs (P < 0.05) increased in the AUTO-Tx group, whereas they all increased in the ALLO-Tx group (P < 0.01). Protein oxidation parameters also changed significantly (P < 0.01) in the ALLO-Tx group but did not in the AUTO-Tx group (P < 0.05). The differences in PGE2 and LTB4 levels were not significant. Histopathologic examination revealed prominent glomerular and tubular injury in the AUTO-Tx and ALLO-Tx groups but less in the ALLO-Tx + BQ group. In the last group, all parameters of lipid peroxidation (P < 0.001 for all) and PCs decreased, and PSs were preserved (P < 0.001 for both) when compared with the AUTO-Tx and ALLO-Tx groups. We conclude that BQ-123, in addition to inhibiting the binding of ET-1,2 to the ETA receptor, may also inhibit the release and/or synthesis of ET-1,2 and prevent reperfusion injury in kidney transplantation.

Topics: Analysis of Variance; Animals; Dinoprostone; Endothelin Receptor Antagonists; Kidney Transplantation; Leukotriene B4; Lipid Peroxidation; Male; Malondialdehyde; Nephrectomy; Oxidation-Reduction; Peptides, Cyclic; Proteins; Rats; Rats, Sprague-Dawley; Rats, Wistar; Receptor, Endothelin A; Renal Circulation; Reperfusion Injury; Transplantation, Autologous; Transplantation, Homologous

The intracellular mechanism for endothelial dysfunction after myocardial ischemia-reperfusion remains to be elucidated. It has been reported that activation of protein kinase C (PKC) occurs after myocardial ischemia-reperfusion and that the activation impairs endothelium-dependent relaxation. Thus we examined the role of PKC activation in the ischemia-reperfusion-induced endothelial dysfunction. Isolated rat hearts perfused with a constant flow were subjected to global ischemia for 15 min followed by reperfusion for 20 min. Coronary vascular responses to the endothelium-dependent vasodilators acetylcholine (ACh) and bradykinin (BK) and the endothelium-independent vasodilator sodium nitroprusside (SNP) were examined before and after the ischemia-reperfusion. Endothelium-dependent relaxations to ACh and BK were impaired after the ischemia-reperfusion, whereas endothelium-independent relaxations to SNP were unaffected. Pretreatment with a PKC inhibitor, staurosporine, H7, or calphostin C, prevented the impairments. Phorbol 12-myristate 13-acetate, a PKC-activating phorbol ester, attenuated the relaxations to ACh and BK but not those to SNP. These results suggest that PKC activation may be involved in part in the ischemia-reperfusion-induced endothelial dysfunction.

Topics: Animals; Endothelin Receptor Antagonists; Endothelium, Vascular; Enzyme Activation; Male; Myocardial Ischemia; Myocardial Reperfusion; Peptides, Cyclic; Protein Kinase C; Rats; Rats, Inbred WKY; Reperfusion Injury; Tetradecanoylphorbol Acetate; Vasodilation

A potential detrimental role of endothelin-1 in myocardial ischemia/reperfusion injury was studied by use of the endothelin-1 antagonists BQ123 and BQ610. Isolated isovolumetric rat hearts were perfused at constant pressure. BQ123 (7 micrograms/min) and BQ610 (1.75 micrograms/min) did not alter mechanical function or coronary flow and shifted dose-response curves for endothelin-1 significantly to the right. In rats subjected to 30 min of no-flow ischemia, the increase of left ventricular resting pressure was significantly delayed by BQ123 and BQ610 compared to control (BQ123: 20 +/- 2* mmHg, BQ610: 19 +/- 2* mmHg, control: 44 +/- 4 mmHg at 15 min of ischemia, respectively, *P < 0.05 v control). With reperfusion after 30 min of ischemia, recovery of left ventricular developed pressure was not significantly affected but tended to be better with endothelin-1 antagonist pretreatment (BQ123: 20 +/- 3 mmHg; BQ610: 19 +/- 3 mmHg, control 12 +/- 3 mmHg). However, in hearts subjected to 15 min of ischemia followed by reperfusion, recovery of left ventricular developed pressure was improved by BQ610 pretreatment (BQ610: 52 +/- 8* mmHg, control: 24 +/- 6 mmHg). We conclude: BQ123 and BQ610 effectively antagonize the coronary constrictive effect of endothelin-1. BQ123 and BQ610 delay the development of contracture during ischemia and may improve functional recovery during reperfusion. Our findings suggest that endogenous endothelin-1 may contribute to ischemia/reperfusion injury.

Topics: Animals; Endothelin Receptor Antagonists; Endothelins; Heart; Heart Rate; In Vitro Techniques; Myocardium; Oligopeptides; Peptides, Cyclic; Rats; Rats, Wistar; Reperfusion Injury; Ventricular Function, Left