Cardioprotection stimulated by resveratrol and grape products prevents lethal cardiac arrhythmias in an animal model of ischemia and reperfusion

Purpose: To evaluate the preventive cardioprotective effects of resveratrol and grape products, such as grape juice and red wine, in animal model of cardiac ischemia and reperfusion. Methods: Male Wistar rats orally pretreated for 21-days with resveratrol and grape products were anesthetized and placed on mechanical ventilation to surgically induce cardiac ischemia and reperfusion by obstruction (ischemia) followed by liberation (reperfusion) of blood circulation in left descending coronary artery. These rats were submitted to the electrocardiogram (ECG) analysis to evaluate the effects of pretreatment with resveratrol and grape products on the incidence of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) resulting from cardiac ischemia and reperfusion. Results: It was observed that the incidence of AVB was significantly lower in rats pretreated with resveratrol (25%), grape juice (37.5%) or red wine (12.5%) than in rats treated with saline solution (80%) or ethanol (80%). Similarly, incidence of LET was also significantly lower in rats pretreated with resveratrol (25%), grape juice (25%) or red wine (0%) than in rats treated with saline solution (62.5%) or ethanol (75%). Conclusion: These results indicate that the cardioprotective response stimulated by resveratrol and grape products prevents the lethal cardiac arrhythmias in animal model of ischemia and reperfusion, supporting the idea that this treatment can be beneficial for prevention of severe cardiac arrhythmias in patients with ischemic heart disease.(AU)

Cardioprotective effects of pharmacological blockade of the mitochondrial calcium uniporter on myocardial ischemia-reperfusion injury

Purpose To evaluate whether the attenuation of mitochondrial Ca2+ overload produced by pharmacological blockade of mitochondrial Ca2+ uniporter (MCU) protects the myocardium against injuries caused by cardiac ischemia and reperfusion (CIR). Methods CIR was induced in adult male Wistar rats (300-350 g) by occlusion of the left anterior descendent coronary artery (10 min), followed by reperfusion (120 min). Rats were treated with different doses of MCU blocker ruthenium red (RuR), administered 5 min before ischemia or reperfusion. Results In untreated rats, the incidences of ventricular arrhythmias (VA), atrioventricular block (AVB) and the lethality (LET) induced by CIR were 85%, 79% and 70%, respectively. In rats treated with RuR before ischemia, the incidences of VA, AVB and LET were significantly reduced to 62%, 25% and 25%, respectively. In rats treated with RuR after ischemia, the incidences of VA, AVB and LET were significantly reduced to 50%, 25% and 25%, respectively. Conclusion The significant reduction of the incidence of CIR-induced VA, AVB and LET produced by the treatment with RuR indicates that the attenuation of mitochondrial Ca2+ overload produced by pharmacological blockade of MCU can protect the myocardium against injuries caused by CIR.(AU)

Pharmacological modulation of b-adrenoceptors as a new cardioprotective strategy for therapy of myocardial dysfunction induced by ischemia and reperfusion

Purpose: To evaluate the cardioprotective response of the pharmacological modulation of β-adrenergic receptors (β-AR) in animal model of cardiac ischemia and reperfusion (CIR), in spontaneously hypertensive (SHR) and normotensive (NWR) rats. Methods: CIR was induced by the occlusion of left anterior descendent coronary artery (10 min) and reperfusion (75 min). The SHR was treated with β-AR antagonist atenolol (AT, 10 mg/kg, IV) 5 min before CIR, and NWR were treated with β-AR agonist isoproterenol (ISO, 0.5 mg/kg, IV) 5 min before CIR. Results: The treatment with AT increased the incidence of VA, AVB and LET in SHR, suggesting that spontaneous cardioprotection in hypertensive animals was abolished by blockade of β-AR. In contrast, the treatment with ISO significantly reduced the incidence of ventricular arrhythmia, atrioventricular blockade and lethality in NWR (30%, 20% and 20%, respectively), suggesting that the activation of β-AR stimulate cardioprotection in normotensive animals. Serum CK-MB were higher in SHR/CIR and NWR/CIR compared to respective SHAM group (not altered by treatment with AT or ISO). Conclusion: The pharmacological modulation of β-AR could be a new cardioprotective strategy for the therapy of myocardial dysfunctions induced by CIR related to cardiac surgery and cardiovascular diseases.(AU)

Cardioprotective effect of preconditioning is more efficient than postconditioning in rats submitted to cardiac ischemia and reperfusion

Purpose: To investigate the cardioprotective effects of ischemic preconditioning (preIC) and postconditioning (postIC) in animal model of cardiac ischemia/reperfusion. Methods: Adult rats were submitted to protocol of cardiac ischemia/reperfusion (I/R) and randomized into three experimental groups: cardiac I/R (n=33), preCI + cardiac I/R (n=7) and postCI + cardiac I/R (n=8). After this I/R protocol, the incidence of ventricular arrhythmia (VA), atrioventricular block (AVB) and lethality (LET) was evaluated using the electrocardiogram (ECG) analysis. Results: After reestablishment of coronary blood flow, we observed variations of the ECG trace with increased incidence of ventricular arrhythmia (VA) (85%), atrioventricular block (AVB) (79%), and increase of lethality (70%) in cardiac I/R group. The comparison between I/R + preIC group with I/R group demonstrated significant reduction in VA incidence to 28%, AVB to 0% and lethality to 14%. The comparison of I/R + postIC group with I/R group was observed significance reduction in AVB incidence to 25% and lethality to 25%. Conclusion: The preconditioning strategies produce cardioprotection more efficient that postconditioning against myocardial dysfunctions and lethality by cardiac ischemia and reperfusion.(AU)

Cardioprotective effect of lipstatin derivative orlistat on normotensive rats submitted to cardiac ischemia and reperfusion

Purpose: To evaluate in vivo animal model of cardiac ischemia/reperfusion the cardioprotective activity of pancreatic lipase inhibitor of the orlistat. Methods: Adult male Wistar rats were anesthetized, placed on mechanical ventilation and underwent surgery to induce cardiac I/R by obstructing left descending coronary artery followed by reperfusion to evaluation of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) with pancreatic lipase inhibitor orlistat (ORL). At the end of reperfusion, blood samples were collected for determination of triglycerides (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), lactate dehydrogenase (LDH), creatine kinase (CK), and creatine kinase-MB (CK-MB). Results: Treatment with ORL has been able to decrease the incidence of VA, AVB and LET. Besides that, treatment with ORL reduced serum concentrations of CK and LDL, but did not alter the levels of serum concentration of TG, VLDL and HDL. Conclusion: The reduction of ventricular arrhythmias, atrioventricular block, and lethality and serum levels of creatine kinase produced by treatment with orlistat in animal model of cardiac isquemia/reperfusion injury suggest that ORL could be used as an efficient cardioprotective therapeutic strategy to attenuate myocardial damage related to acute myocardial infarction.(AU)

Effect of atenolol pre-treatment in heart damage in a model of intestinal ischemia-reperfusion

Purpose: To investigate the effects of atenolol in inflammatory mediator and oxidative stress in a myocardial injury by intestinal ischemia/reperfusion in rat model. Methods: Adult Wistar male rats were randomly (n=8), anesthetized and divided in: Sham: submitted to operation only; group SS+IR: intravenous saline infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); group AT+IR: intravenous atenolol infusion (2 mg/kg) following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); and group AT+I+AT+R: intravenous atenolol infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and in the time 45 minutes other atenolol doses were administrated and the artery was open for 120 minutes (reperfusion), all animals were submitted to muscular relaxation for mechanical ventilation. In the end of experiment the animals were euthanized and the hearts tissue were morphology analyzed by histology and malondialdehyde by ELISA, and the plasma were analyzed for tumor necrosis factor-alpha by ELISA. Results: The group SS+IR demonstrated the higher malondialdehyde levels when compared with the atenolol treated-groups (p=0.001) in the heart tissue. The tumor necrosis factor-alpha level in plasma decrease in the treated groups when compared with SS+IR group (p=0.001). Histology analyses demonstrate pyknosis, edema, cellular vacuolization, presence of inflammatory infiltrate and band contraction in the heart tissue of the rats. Conclusion: Atenolol significantly reduce the degree of cardiac damage after intestinal ischemia-reperfusion.(AU)

Heparin modulates the expression of genes encoding pro and anti-apoptotic proteins in endothelial cells exposed to intestinal ischemia and reperfusion in rats

PURPOSE: To investigate if expression of genes encoding pro and anti-apoptotic proteins in the rat enteric endothelial cells stimulated by intestinal ischemia followed by reperfusion (IR) can be modified by treatment with heparin (HP). METHODS: Eighteen adult Wistar rats were divided in three groups: sham group submitted to laparotomy only (SG), ischemia followed by reperfusion group (IRG); ischemia followed by reperfusion plus pretreatment with HP 100 mg.kg-1 (IRG+HP). Ischemia was performed by clamping of the superior mesenteric artery. After 60 min of ischemia, metal clamps were removed for reperfusion for 120 min. Gene expression of encoding pro (Casp1, Casp6, Casp3, Cflar, Fas and Pgl) and anti-apoptotic (Bcl2, Bcl2l1 and Naip2) proteins in rat enteric endothelial cells was evaluated by PCR microarray method. RESULTS: Compared to rat endothelial cells of SG, the expression of pro-apoptotic genes was up-regulated in IRG while anti-apoptotic genes were down-regulated. In contrast, the expression of anti-apoptotic genes in IRG+HP was up-regulated while pro-apoptotic genes was down-regulated compared to SG. CONCLUSION: The attenuation by heparin of intestinal ischemia-reperfusion previously demonstrated in rodents could be related with ability of this drug to stimulate and reduce gene expression of encoding anti and pro-apoptotic proteins, respectively. (AU)

Ischemic preconditioning and the gene expression of enteric endothelial cell biology of rats submitted to intestinal ischemia and reperfusion

PURPOSE: To investigate the effects of ischemic preconditioning (IPC) on the expression of pro and anti-apoptotic genes in rat endothelial cells undergoing enteric ischemia (I) and reperfusion (R). METHODS: Thirty rats underwent clamping of the superior mesenteric vessels. Sham group (GS) laparotomy only; Ischemia (GI): intestinal ischemia (60 min); Ischemia and Reperfusion (GIR): ischemia (60 min) and reperfusion (120 min); Ischemia and intestinal ischemic preconditioning (GI + IPC) : 5 minutes of ischemia followed by 10 min of reperfusion before sustained ischemia (60 min) ischemia and reperfusion and IPC (GIR + IPC): 5 min ischemia followed by 10 min of reperfusion before sustained ischemia (60min) and reperfusion (120 min). Rat Endothelial Cell Biology (PCR array) to determine the expression of genes related to endothelial cell biology. RESULTS: Gene expression of pro-apoptotic markers (Casp1, Casp6, Cflar, Fas, and Pgl) was down regulated in GI+IPC and in GIR + IPC. In contrast, the expression of anti-apoptotic genes (Bcl2 and Naip2), was up-regulated in GI + IPC and in GIR + IPC. CONCLUSION: Ischemic preconditioning may protect against cell death caused by ischemia and reperfusion.(AU)

L-arginine in the ischemic phase protects against liver ischemia-reperfusion injury / A L-arginina durante a fase isquêmica protege o fígado das lesões de isquemia e reperfusão

PURPOSE: To investigate the effects of intravenous L-arginine (LG) infusion on liver morphology, function and proinflammatory response of cytokines during the early phase of ischemia-reperfusion injury (IRI). METHODS: Thirty rabbits were subjected to 60 minutes of hepatic ischemia and 120 minutes of reperfusion. An intravenous injection of saline or L-arginine was administered five minutes before the ischemia and five minutes before initiating the reperfusion and at the 55th and 115th minutes after the ischemia. Samples were collected for histological analysis of the liver and measurements of the serum AST, ALT and LDH and the cytokines IL-6 and TNF-alpha. RESULTS: It was observed a significant reduction of sinusoidal congestion, cytoplasmic vacuolization, infiltration of polymorphonuclear leukocyte, nuclear pyknosis, necrosis and steatosis in liver tissue, as well as AST, ALT and LDH after injection of LG in the ischemia (p <0.001). Lower levels of IL-6 and TNF-alpha were associated with LG infusion during ischemia. Higher levels these proteins were observed in animals receiving LG during reperfusion. CONCLUSION: L-arginine protects the liver against ischemia/reperfusion injury, mainly when is administered during the ischemic phase.(AU)

OBJETIVO: Investigar os efeitos da infusão endovenosa da L-arginina (LG) na morfologia, função e resposta de citocinas pró-inflamatórias do fígado durante a fase precoce da lesão de isquemia e reperfusão (IRI). MÉTODOS: Trinta coelhos foram submetidos a 60 minutos de isquemia hepática e 120 minutos de reperfusão. Foi administrada injecção intravenosa de solução salina ou L-arginina aos cinco minutos antes de iniciar a isquemia e cinco minutos antes de iniciar a reperfusão e aos 55 e 115 minutos após o início da isquemia. Realizou-se análise histológica do fígado e dosagens séricas de AST, ALT, LDH, citocinas IL-6 e TNF-alfa. RESULTADOS: Ocorreu redução significante da congestão sinusoidal, vacuolização citoplasmática, infiltração de leucócitos polimorfonucleares, picnose nuclear, necrose e esteatose no tecido hepático, assim como nos níveis de AST, ALT e LDH após a injeção da LG na isquemia (p<0,001). Níveis mais baixos de IL-6 e TNF-alfa foram associados com a infusão LG durante a isquemia. Níveis mais elevados dessas proteínas foram observados nos animais que receberam LG durante a reperfusão. CONCLUSÃO: A L-arginina protegeu o fígado contra a lesão de isquemia e reperfusão principalmente quando administrada durante a fase de isquemia.(AU)