Abstract: Objective: To investigate the protective effects of xuebijing (XBJ, Traditional Chinese Medicine Complex) injection on cardiac function in rats with myocardial hypoxia/reoxygenation(H/R) injury. Methods: The isolated langendorff perfused rat heart model was established. One hundred and thirty SD rats were randomly divided into sham group, hypoxia/reoxygenation group, low dose XBJ(XBJ_L) group, middle dose XBJ(XBJ_M) group and high dose XBJ(XBJ_H) group. All groups except sham group were divided into three subgroups according to reoxygenation time(0.5 h,1 h, 2 h) (n=10). In sham group, left ventricular development pressure(LVDP), maximal rates of increase/decrease of the left ventricular pressure(±dp/dt_max), left ventricular pressure (LVP), and heart rates (HR) were recorded after 20 minutes balance perfusion. The creatine kinase-MB (CK-MB) in myocardium was detected by ELISA. In other groups, after 20 minutes balance perfusion, we perfused ThomasⅡto stop the hearts from beating for 30 minutes, then reperfused the K-H until hearts recover beating. The microstructure of myocardium was observed under light microscopy. LVDP, ±dp/dt_max, LVP and HR were continuously recorded in other four groups and the concentrations of CK-MB in myocardium were measured by ELISA at different time points after reoxygenation. Microstructure of myocardium in each group were observed under light microscopy. Results: LVDP, ±dp/dt_max, LVP and HR of other groups were significantly lower than those of sham group(P<0.05). The levels of CK-MB were higher than that of sham group(P<0.05). LVDP, ±dp/dt_max, LVP and HR of XBJL, XBJM and XBJH groups were higher than those of I/R group at corresponding time points after reoxygenation(P<0.05). The levels of CK-MB were lower than that of I/R group(P<0.05) and the cardiac function was improved. The middle dose of XBJ had the best protective effect. Conclusion: Xuebijing injection can effectively improve cardiac function and structure in rats with myocardial hypoxia/reoxygenation injury, and middle dose of XBJ is the best.

Key words: myocardium, hypoxia/reoxygenation, xuebijing (Traditional Chinese Medicine complex) injection, cardiac function, cardiac structure, rats