Protective effect of polydatin against ischemia/reperfusion injury in rat heart.

The aim of the present study was to investigate the protective effect of polydatin against myocardial ischemia/reperfusion injury in rats and the underlying mechanism. In anesthetized rats, ischemia and reperfusion arrhythmia produced by ligating and loosing the coronary artery was recorded and myocardial infarct size was measured. In Langendorff isolated rat heart, cardiac function was recorded before and after 30 min of global ischemia followed by 60 min of reperfusion. The parameters of cardiac function include left ventricular developed pressure (LVDP), maximal differentials of LVDP (±LVdp/dt(max)) and coronary flow (CF) were measured. Myocardial superoxide dismutase (SOD) activity, the contents of myocardial malondialdehyde (MDA) and nitric oxide (NO) as well as the activity of nitric oxide synthase (NOS) were measured in isolated heart. The results showed: (1) Arrhythmia score and myocardial infarct size were significantly lower in polydatin group than that in the control group (P<0.05, P<0.01); (2) The recovery of LVDP, ±LVdp/dt(max) and CF during reperfusion in polydatin group were significantly better than that in the control rats (P<0.05, P<0.01); (3) SOD activity in polydatin group was significantly higher than that in the control group, but MDA content was lower in polydatin group than that in the control group (P<0.05); (4) NO content and NOS activity, especially constitutive nitric oxide synthase (cNOS) activity in polydatin group were higher than that in the control group (P<0.05); (5) L-NAME, the NOS inhibitor, reversed the protective effect of polydatin against ischemia/reperfusion injury. The results suggest that polydatin has a protective effect against ischemia/reperfusion injury in rat heart. The cardioprotection of polydatin is mainly mediated by cNOS which leading to an increase in NO production.