Abstract: AIM: To investigate myocardial protective effects of the polydatin (polydatin, PD) on ischemia-reperfused rat hearts in vitro. METHODS: Forty SD rats were randomly divided into four groups: ischemia-reperfusion group (I/R group), PD group (I/R+PD group), polydatin+protein kinase C(PKC) inhibitor group (I/R+PD+CHE group) and PKC inhibitor group (I/R+CHE group). The isolated rat heart was perfused at a Langendorff apparatus and ischemia 40 min and reperfusion 40 min were performed. The heart function parameters, including heart rate, left ventricular systolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal velocity of increase and decrease of ventricular pressure (±dp/dtmax), and the concentration of phosphate kinase (PK) and lactate dehydrogenase (LDH) were analyzed at different time points (20 min and 40 min after reperfusion). RESULTS: Myocardial ischemia and reperfusion resulted in myocardial injuries. LVDP and LV±dp/dtmax decreased while LVEDP increased in I/R group, with increases in PK and LDH leakage and MDA level and decreases in SOD level. The changes in the abovementioned cardiac functions, myocardial enzyme activity and MDA or SOD level were significantly attenuated in I/R+PD group (P<0.05). The effects of PD were abolished by CHE, a selective PKC inhibitor. CONCLUSION: PD plays a protective role in ischemia-reperfusion myocardium and the cardioprotective effect of PD maybe via PKC dependent signaling pathway.