Abstract: Objective    To investigate the effects of sodium tanshinone IIA sulfonate on cardiac function and immune response in rats with myocardial ischemia-reperfusion (I/R) injury and its mechanism.    Methods    The model of myocardial ischemia-reperfusion was established by coronary artery ligation. The rats were randomly divided into five groups: Ctrl group, I/R group, I/R+TIIA (0.5 mL), I/R+TIIA (1 mL) group and I/R+TIIA (2 mL) group. The mean ventricular systolic pressure (MAP), left ventricular systolic pressure (LV) and heart rate (HR) were measured. The expression of heart damage markers and the content of oxidative stress indicators were detected by Elisa test. HE staining and TUNEL staining were used to evaluate myocardial injury. The changes of CD4+iNOS+ and CD4+IL-10+ apoptosis in peripheral blood were evaluated by flow cytometry. Western blotting was used to detect the expression of apoptosis-related proteins and P65, IL-8 and TNF-α.    Results    Sodium tanshinone II A sulfonate injection could up-regulate the levels of MAP, HR and LVSP to improve the cardiac function of I/R model rats (P<0.01), reduce the expression of CK-MB, cTnΙ and MB in serum, and reduce the expression of MDA and LDH while increase SOD, improve the pathological changes of myocardial tissue, inhibit myocardial apoptosis, and up-regulate Bcl-2 and down-regulate the Bax (P<0.01), decrease apoptosis of iNOS+ and increase IL-10+ in order to improve Th1/Th2 balance (P<0.01), inhibit the down-regulation of P-P65, IL-8 and TNF-α expression induced by I/R injury (P<0.01).    Conclusions    Sodium tanshinone IIA sulfonate injection has protective effect on myocardial ischemia-reperfusion injury which is related to improving cardiac function and regulating immune response.

Key words: Sodium tanshinone IIA sulfonate, 　MAP, 　LVSP, 　Th1/Th2