Abstract: Objective To investigate the effects of deer velvet antler on cardiomyocyte apoptosis and expressions of apoptosis-related proteins Bcl-2, Bax, and caspases in a rat model of myocardial infarction. Methods A rat model of myocardial infarction was established via ligation of the left anterior descending coronary artery. The sham-operated group (n=10) was sutured without ligation. Twenty rats in the myocardial infarction model were randomly divided into the model group and the deer antler velvet group, with 10 rats in each. The deer antler velvet group received 400 mg·kg^-1·d^-1 deer antler velvet powder via gastric intubation while the shamoperated and model groups received an equal volume of 0.5% sodium carboxy-methylcellulose daily. After one week of intervention, cardiac function was evaluated via echocardiography. HE staining was used to examine the pathology of myocardial tissues while immunofluorescence was adopted to detect the expression of F-actin. ELISA was used to detect levels of serum tumor necrosis factor-α (TNF-α). TUNEL assay was employed to determine the myocardial cell apoptosis rate in the infarct border zone. Bcl-2 and Bax expressions in this zone were detected via immunohistochemistry, and Bcl-2, Bax, Caspase-3, and Caspase-9 protein expressions via Western blotting. Results Compared with the sham-operated group, the left ventricular short-axis fraction shortening (FS) and left ventricular ejection fraction (EF) of rats in the model group were significantly reduced (P<0.01) while theeft ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), end-systolic volume (ESV), and end-diastolic volume (EDV) were significantly increased (P<0.01). Hematoxylin and eosin (HE) staining revealed marked pathological changes in myocardial tissues, including disorderly F-actin and dissolution of the myocardial cytoskeleton. Serum TNF-α levels and myocardial cell apoptosis rates were significantly elevated (P<0.01). Immunohistochemistry and Western blotting both pointed to decreased Bcl-2 expressions and increased Bax expressions in the model group. Western blotting suggested significantly elevated Caspase-9 and Caspase-3 protein expressions (P<0.05, P<0.01). Compared with the model group, rats in the deer antler velvet group showed significantly increased EF and FS (P<0.01) but significantly decreased LVEDD, LVESD, EDV, and ESV (P<0.01). Hematoxylin and eosin staining indicated reduced sizes of myocardial lesions and effective repair of myocardial F-actin structure in the deer antler velvet group. Serum TNF-α levels and myocardial cell apoptosis rates decreased in the deer antler velvet group (P<0.05). Bcl-2 protein expressions increased while Bax, Caspase-9 and Caspase-3 protein expressions decreased in the deer antler velvet group P<0.05, P<0.01). Conclusion Deer antler velvet may target the balance between Bcl-2/Bax apoptosis-related proteins, block the Caspase-9/Caspase-3 cascade activation mediated through the mitochondrial pathway, reduce myocardial cell apoptosis in rats with acute myocardial infarction, and exert cardioprotective effects.

Key words: Deer Antler Velvet, Acute Myocardial Infarction, Cardiomyocyte Apoptosis, Bcl-2/Bax/Caspase Apoptosis-Related Proteins, TNF-α, Rats