Objective: To observe the protective effect of Yixinnao dripping pills (YXN) on myocardial ischemia reperfusion injury (I/R) in Wistar rats. Method: The rats were randomly divided into six groups: sham-operated (sham) group

I/R group (I/R)

Diao Xinxuekang(DAXXK

0.07 g·kg-1) treated group

high

medium and low dose groups pretreated by YXN (3

1.5

0.75 g·kg-1)

each group orally administered 7 days.Then

the left anterior descending coronary artery was ligated for 30 min

followed by 60 min of reperfusion to establish the rat myocardial ischemia-reperfusion injury model.Hemodynamic and electrocardiogram(ECG) were observed continuously

and ventricular arrhythmias were measured.At the end of reperfusion

the serum malondialdehyde (MDA) concentration and superoxide dismutase(SOD)activity were measured.The myocardial infarct size was measured after reperfusion. Result: Heart rate(HR)

left ventricular systolic pressure(LVSP)

the maximum rise rate of left ventricular pressure (+dp/dtmax) and the maximum descending of left ventricular pressure (-dp/dtmax) and activity of SOD decreased obviously in I/R group compared with those in sham group; MDA content increased obviously (P<0.01) and the area of necrosis(An)/area at risk(AAR) was significantly elevated (P<0.05) in the I/R group. Compared with I/R

YXNH could significantly improve the HR

LVSP

±dp/dtmax and reduce the LVEDP(P<0.01 or P<0.05)

decrease the lasting time of ventricular arrhythmias(P<0.01); the activity of SOD was obviously increased

and MDA content was decreased (P<0.01); the An/AAR was smalle r(P<0.01).The effect was similar to that of DAXXK.YXNM and TXNL also had protective effect on I/R in rats

but their effect was not as good as DAXXK. Conclusion: YXN has protective action on I/R in rats

which may be related to promoting the functions of myocardium and enhancing the antioxidant ability.