Effects of testosterone on heart function following heart failure after myocardial infarction in rats

Objective To investigate the effects of low dose testosterone on heart function,and ventricular remodeling in male rats with postinfarction congestive heart failure(CHF).Methods Sixty SD rats were undergone surgery,of which,45 rats were performed coronary artery ligation and other 15 were sham group (PS group).Six weeks later,left ventricular function of survived rats was examined by echocardiography,and LVEF≤45％ was defined as the standard of successful CHF model.All survived model rats were randomly divided into 2 groups:TU group(n =16) treated with TU 5 mg/kg per 2 weeks intramuscular injection;placebo (PL) group (n =16) treated with PL.Mter treatment for 12 weeks,left ventricular ejection fraction(LVEF) was assessed by echocardiography again.Serum testosterone level was determined by radioimmunoassay.The expression of tumor necrosis factor-or (TNF-α) mRNA and matrix metalloproteinase (MMP)-9mRNA in myocardial tissue was measured by RT-PCR.Results In male post-myocardial infarction rats,serum testosterone level and LVEF were decreased significantly than PS group(P ＜ 0.05),and the expression of TNF-α mRNA and MMP-9 mRNA in myocardial tissue was increased significantly than PS group (P ＜ 0.05).Mter low dose TU therapy,LVEF of rats in TU group improved significantly(P ＜0.05),and the expression of TNF-α mRNA and MMP-9 mRNA in myocardial tissue was reduced significantly (P ＜ 0.05).Meanwhile,the mortality was decreased (P ＜ 0.05).Conclusion Low dose testosterone therapy can restore the inflammatory imbalance and suppress the ventricular remodeling in male post-myocardial infarction rats and improve left ventricular function,as well as reduce mortality. Key words: Heart failure;  Testosterone;  Rats ;  tumor necrosis factor-or ;  matrix metalloproteinase-9 ;  Immunomodulatory therapy