| ObjectiveResveratrol, an effective activator of NAD-dependent class Ⅲ histone/nonhistone deacetylase Sirtl, attenuates apoptosis of cardiomyocytes induced by ischemia and reperfusion injury. The aim of this study is to investigate the role of Sirtl-p53pathway in the anti-apoptotic effect of resveratrol on myocardial ischemia/reperfusion injury.Methods48male Sprague-Dawley rats,10～13weeks old, weighed200～250g, were randomly divided into four groups(n=12):ischemia/reperfusion group(IR), Resveratrol treatment group(RES+IR), Resveratrol and Sirt1specific inhibitor EX527treatment group(RES+EX+IR) and EX527treatment group(EX+IR group). The myocardial ischemia/reperfusion injury model in rats was established by ligating left anterior descending coronary artery for45minutes and then reperfusing the myocardial tissue for2hours.(1) Group IR:DMSO and PBS mixture (DMSO:PBS=1:1)(volume:1ml) was administered15min before the ligation through the sublingual vein.(2) Group RES+IR:Resveratrol was administered (20mg/kg)(volume:1ml)15min before the ligation through the sublingual vein.(3) Group RES+EX+IR:Sirtl inhibitor EX527(1μg/kg) and resveratrol (20mg/kg)(total volume:1ml) were simultaneously administered15min before the ligation through the sublingual vein.(4)Group EX+IR:Sirtl inhibitor EX527(volume:1ml) was administered15min before the ligation through the sublingual vein. After the indicated treatment, the apoptotic ratio of cardiomyocytes was detected with TUNEL method. The pro-apoptotic protein BAX was determined with immunohistochemistry. The expressions of Sirtl and acetyl-p53(Lys373&382) were measured with Western blot.Results1Comparison of the apoptotic ratio of ischemia/reperfusion-stressed cardiomyocytes:Compared with in group IR, The apoptotic ratio of cardiomyocytes in group RES+IR was markedly decreased (P<0.05). Compared with in group RES+IR, the apoptotic ratio of cardiomyocytes in group RES+EX+IR was elevated significantly (P<0.05). There was no significant difference in the apoptotic ratio of cardiomyocytes in between group IR and group EX+IR (P>0.05).2Comparison of the expressions of pro-apoptotic protein BAX in ischemia/reperfusion-stressed myocardial tissue:Compared with in group IR, The expression of BAX protein in group RES+IR was markedly decreased (P<0.05). Compared with in group RES+IR, the expression of BAX protein in group RES+EX+IR was elevated significantly (P<0.05). There was no significant difference in the expression of BAX protein in between group IR and group EX+IR (P>0.05).3Comparison of the expressions of Sirtl protein and ac-p53(lys373&382) in ischemia/reperfusion-stressed myocardial tissue: Compared with in group IR, The expression of Sirtl protein in group RES+IR was markedly elevated (P<0.05). Compared with in group RES+IR, the expression of Sirtl protein in group RES+EX+IR was significantly decreased (P<0.05). There was no significant difference in the expression of Sirtl protein in between group IR and gr oup EX+IR (P>0.05).Compared with in group IR, The expression of ac-p53(lys373&382) in group RES+IR was markedly decreased (P<0.05). Compared with in group RES+IR, the expression of ac-p53(lys373&382) in group RES+EX+IR was elevated significantly (P<0.05). There was no significant difference in the expression of ac-p53(lys373&382) in between group IR and group EX+IR (P>0.05).ConclusionsResveratrol can prevent cardiac myocytes from ischemia/reperfusion-induced apoptosis, the mechanism of which is probably up-regulation of the expression of cardioprotective protein Sirtl and subsequently inactivation of p53through deacetylation of p53at lysine 373and382. |
PDF Full Text Request