To investigate whether Shengmai injection (SMI) helps to improve cardiac function and enhances angiogenesis after myocardial ischaemia reperfusion injury (MIRI). A rat model of MIRI was created via occlusion of the left anterior descending coronary artery for 30 min, followed by 3 days or 7 days of reperfusion (n = 6 each group).

SMI is widely used for the treatment of myocardial infarction. The mechanism underlying the effect on cardiac function is not known and whether SMI has any effects on angiogenesis during treatment of MIRI is not clear.

Echocardiography showed that SMI improved the left ventricular ejection fraction (LVEF) in the rat model of MIRI. TUNEL staining indicated that SMI decreased the myocardial apoptosis rate after MIRI. This result may be related to the increase of Bcl-2 expression in the SMI group and a reduction in Bax and caspase 3 expression, as determined by immunohistochemical staining. Small vessels (<60 μm in diameter) of the heart of rats in the group treated with SMI were denser (more numerous) than those in the heart of rats in the other groups. Real-time PCR indicated that the SMI-driven reduction in apoptosis was associated with a change in the ratio of Bcl-2 to Bax expression, and treatment-induced angiogenesis was associated with enhanced vascular endothelial growth factor A (VEGF) expression. We elucidated that SMI promotes angiogenesis, which is important for the development of cardiac remodelling after MIRI.