Effects of Panax quinquefolium saponin on mitochondrial membrane po-tential and cardiomyocyte apoptosis in ischemia/reperfusion rats / 中国病理生理杂志

ABSTRACT

AIM:To investigate whether mitochondrial membrane potential (ΔΨm ) and the mitochondrial ap-optotic pathway are involved in the protective mechanism of Panax quinquefolium saponin ( PQS) against cardiomyocyte ap-optosis after ischemia/reperfusion ( I/R) injury in rat myocardium .METHODS: Ninety healthy male SD rats were ran-domly divided into sham group , I/R group, PQS (200 mg· kg -1 · d-1 ) +I/R group, cyclosporine A ( CsA) group, CsA (10 mg· kg-1 ) +I/R group and PQS +CsA +I/R group.The model of myocardial I/R injury in vivo was established by ligating the left anterior descending artery ( LAD) for 30 min followed by 120 min of reperfusion in the rats .The serum ac-tivity of lactate dehydrogenase ( LDH ) was measured by automatic chemistry analyzer .The myocardial infarct size was measured by Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining.Cardiomyocyte apoptosis was detected by in situ TDT-mediated dUTP nick end labeling (TUNEL).The protein levels of Bcl-2, Bax, cleaved caspase-3 and cytosol-ic cytochrome C were determined by Western blotting .ΔΨm was measured by laser scanning confocal microscopy and fluo-rescence microplate reader .RESULTS:Compared with I/R group, the serum content of LDH ,the infarction size in PQS+I/R group, CsA+I/R group and PQS +CsA+I/R group and the myocardial apoptotic index were decreased .Compared with I/R group, the fluorescence intensity of mitochondria after JC-1 staining was enhanced in PQS +I/R group, CsA+I/R group and PQS+CsA+I/R group, and the relative fluorescence units (RFU) ofΔΨm were improved in those 3 groups. In PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group, the protein expression of Bcl-2 was increased, and that of Bax was decreased compared with I/R group.Moreover, in those 3 groups, the protein levels of cleaved-caspase-3 and cytosolic cytochrome C were decreased compared to I /R group, respectively.CONCLUSION:PQS attenuates myocardial injury and cardiomyocyte apoptosis during I /R, and the protective mechanisms of PQS were associated with the modulation ofΔΨm and the inhibition of mitochondrial apoptosis pathway .