Achyranthes bidentata polypeptides reduce oxidative stress and exert protective effects against myocardial ischemic/reperfusion injury in rats

AIM To investigate the effects of achyranthes bidentata polypeptides (ABPP) preconditioning on myocardial ischemia/reperfusion (MI/R) injury and to explore the possible mechanism. METHODS Male Sprague Dawley (SD) rats were randomly divided into three groups: sham, myocardial ischemia reperfusion (MI/R) and ABPP+MI/R. The model of myocardial I/R injury in vivo was made by ligating the left anterior descending artery for 30 min followed by 4 h of reperfusion in SD rats. Hemodynamics were measured and myocardial infarct size was measured by Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining. The level of hyperoxide superoxide, malondialdehyde (MDA) and plasma creatine kinase (CK) were measured and the activities of antioxidant enzyme superoxide dismutase (SOD) and lactate dehydrogenase (LDH) were detected. The gp91phox was determined by Western blot, cardiomyocyte apoptosis was detected using in situ TDT-mediated dUTP nick end labeling (TUNEL), activity of caspase-3 was determined by fluorescent assay and gp91phox was determined by Western blot. RESULTS Compared with those in the I/R group, left ventricular ±dp/dtmax in ABPP preconditioned rats increased significantly (P<0.05). The percentage of area of necrosis was reduced ［(36.0±3.0)% vs.(26.5±3.5)%, P<0.05］. Plasma CK and LDH levels decreased, respectively, to (1251±72) U/L and (1961±122) U/L (P<0.05 vs. MI/R). ABPP preconditioning decreased superoxide accumulation (P<0.05 vs. MI/R) and decreased gp91phox expression (P<0.05). Compared with those in the MI/R group, apoptosis index and expressions of caspase-3 were significantly attenuated in ABPP preconditioned animals (P<0.05). ABPP preconditioning markedly decreased gp91phox expression (P<0.05). CONCLUSION ABPP reduces oxidative stress and exerts cardioprotection against MI/R injury in rats.