Background To study the protective effect and potential mechanism of Guanxinkeli (GXKL) which may plays an important role in resisting the reperfusion injury of the ischaemic myocardium on myocardial ischemia and reperfusion injuries.

Methods Thirty-six rats were randomly divided into three groups: control group, ischemia reperfusion injury group and GXKL group, there were 12 rats in each group. The rat hearts were subjected to 15 min ischemia, followed by 30 min reperfusion. HR, LVDP, LVEDP and ± dp /dtmax were recorded before ischemia and at 30 min of reperfusion. The coronary effulents were collected before ischemia and at 30 min of reperfusion to measure the CK and LDH activity and the arrhythmia scores were determined. JNK protein Level was derermined by western blotting assay.

Results GXKL enhanced LVEDP, LVDP and ± dp /dtmax. The arrhythmia score, CK and LDH activities in GXKL group were lower than those in ischemia and reperfusion group. The phosphorylated JNK protein was also lower in GXKL group.

Conclusions GXKL may obviously improve the anti-ischaemic myocardial ischemia/reperfusion ability, increase myocardial contraction force, alleviate arrhythmia, the protective effect may be correlated with JNK signalling pathway.