Abstract:【Abstract】Objective To investigate the effects of genistein on the proteins and mRNA expression of Bcl2, Bax and Caspase3 in myocardial of myocardial ischemia reperfusion injury (MI/RI) rats. Methods 60 male SpragueDawley rats were divided into sham operation group, model group, positive drug aspirin group (10 mg/kg/d), genistein low dose group (20 mg/kg/d), middle dose group (40 mg/kg/d) and high dose group (80 mg/kg/d). After 2 weeks of drug administration, the MI/RI rat model was constructed base on classical method, and then HE staining was used to detect myocardial pathology. The serum was collected for detecting the lactate dehydrogenase (LDH), Creatine kinase (CK), Creatine kinase isoenzymes (CKMB) and αhydroxybutyrate dehydrogenase (αHBD). The myocardial was collected for detecting the malondialdehyde (MDA), superoxide dismutase (SOD), total antioxidant capacity (TAOC) and nitric oxide synthase (NOS). The proteins and mRNA expression characteristics of Bcl2, Bax and Caspase3 were detected by RTPCR and Western Blotting. Results In the sham operation group, the myocardial arrangement was orderly without rupture, while in the model group, there were a lot of fractures. Compared with the model group, the serum LDH, CK, CK MB and α HBD of the model group were higher than those of the sham operation group (P<005), the myocardial MDA level was higher than that of the sham operation group (P<005), and the myocardial SOD, t AOC and NOS levels were lower than those of the sham operation group (P<005). Compared with the model group, LDH, CK, CK MB, αHBD, MDA, SOD, t AOC and NOS in the three dose groups of genistein and aspirin group were significantly decreased (P<005), while SOD, t AOC and NOS were significantly increased (P< 005). In the model group, the expression of Bcl2 protein and mRNA was lower than that in the sham operated group (P<005), and the expression of Bax and caspase3 protein and mRNA was higher than that in the sham operated group (P<005), while in the three dose groups of genistein and aspirin group, Bcl2 was significantly upregulated (P<005), Bax and caspase3 was significantly down regulated (P<005). ConclusionGenistein can inhibit myocardial cell apoptosis, increase myocardial antioxidant capacity, and inhibit myocardial ischemiareperfusion injury.