Protective effect of TGF-β-Smads signal-based oxymatrine on myocardial fibrosis induced by acute myocardial infarction in rats

OBJECTIVE: To study the protective effect of oxymatrine (OMT) on myocardial fibrosis induced by acute myocardial infarction in rats and its effect on TGF-beta-Smads signal pathway. METHOD: Arteria coronaria ligation-induced acute myocardial infarction model was established in rats. The survived rats were randomly allotted into the model group, 50, 25, 12.5 mg x kg(-1) OMT groups, the 50 mg x kg(-1) captopril group, and the Sham-operated group which was treated as the model group without the arteria coranaria ligation. After 8 weeks of ligation, myocardial fibrosis was detected by HE and Masson staining, and the RT-PCR method were used to detect the expression of mRNA of TGF-beta-Smads signal system. RESULT: The histopathological examination showed decrease in cardiocytes, deposition of extra-cellular matrix, and increase of collagen contents after 8 weeks of ligation. RT-PCR results showed that mRNA expressions of TGF-beta1, TbetaR1, Smad2, Smad3 and Smad4 significantly increased, but mRNA expression of Smad7 is remarkable lower than the sham-operated group. Treatment with OMT for 8 weeks could remarkably inhibit myocardial fibrosis, decrease mRNA expressions of TGF-beta1, TbetaR1, Smad2, Smad3, and Smad4, and increase mRNA expressions of Smad7. CONCLUSION: OMT has the inhibitory effect on the experimental myocardial fibrosis induced by AMI in rats. Its mechanism may be closely related to TGF-beta-Smads signal system.