ABSTRACT
<p><b>OBJECTIVE</b>To explore the effects of Sini Decoction (SD) on the expressions of Samd2 and Smad7 isoproterenol (Iso) induced myocardial fibrosis rats.</p><p><b>METHODS</b>Totally 19 Wistar rats were randomly divided into 3 groups, i.e., the control group, the model group, and the SD group. Iso was injected to rats in the model group and the SD group, while normal saline was injected to rats in the control group. SD was given to rats in the SD group by gastrogavage, while normal saline was administered to rats in the control group and the model group by gastrogavage. Four weeks later Masson staining and electron microscopic analysis were performed in each group. The protein and mRNA expressions of Smad2 and Smad7 were detected using immunohistochemical assay and RT-PCR.</p><p><b>RESULTS</b>Masson staining showed the IOD value of the myocardial collagen fiber was 9 303 in the model group, 2 459 in the SD group, and 4 224 in the control group, indicating the myocardial fibrosis was more obvious in the model group than in the SD group and the control group. The IOD value of Smad2 protein was 20 275 and the mRNA IOD of Smad2 protein was 0. 919 in the model group, while they were respectively 9 949 and 0. 561 in the SD group, indicating the protein and mRNA expressions of Smad2 were obviously higher in the model group than in the SD group (P < 0.05). The IOD value of Smad7 protein was 25 667 and the mRNA IOD of Smad7 protein was 0.222 in the model group, while they were respectively 93 147 and 0. 412 in the SD group, indicating the protein and mRNA expressions of Smad7 was obviously lower in the model group than in the SD group (P < 0.05).</p><p><b>CONCLUSION</b>SD could effectively inhibit Iso induced myocardial fibrosis, and its mechanism may be associated with down-regulating the expression of Smad2 and up-regulating the expression of Smad7.</p>