RESUMO
OBJECTIVES: Stably expressed transforming growth factor -beta 1(TGF-ß1)MCs were obtained and the effects of centellaasiatica (CA) granule on the expressions of Smad 2/3, Smad 7 and collagen â £ and the level of Smad 2/3 phosphorylation were observed. METHODS: Lipofectin method was used to transfect TGF-ß1 vector into MC, and the stably expressed TGF-ß1 cell lines were selected by G418. The cells were divided into three groups. Control group:normal MC + RPMI 1640 + 10% normal rat serum; TGF-ß1 group:stably expressed TGF-ß1 MC + RPMI 1640 + 10% normal rat serum; CA group:stably expressed TGF-ß1 MC + RPMI 1640 + 10% rat serum containing high CA. The experiments were repeated for five times. The contents of TGF-ß1 and collagen â £ in the culture medium were detected with ELISA, the expressions of mRNA and protein of TGF-ß1, Smad 2/3, Smad 7 and the level of Smad 2/3 phosphorylation were detected by using real time quantitative polymerase chain reaction and Western blot. RESULTS: The contents of TGF-ß1 and collagen â £ in the culture medium of stably-expressed TGF-ß1 MC were increased significantly, and the CA could reverse the effects of TGF-ß1. The expressions of mRNA and protein of TGF-ß1, Smad 2/3 and the level of Smad 2/3 phosphorylation were increased significantly in TGF-ß1 transfected MC, and CA could dramatically reduce the expressions of mRNA and protein of TGF-ß1, Smad 2/3 and the level of Smad 2/3 phosphorylation. The high expression of TGF-ß1 decreased the expression of Smad 7 mRNA and protein, and the CA could antagonize the effect of mRNA expression. CONCLUSIONS: The MCs stably-expressed TGF-ß1 can activate the TGF-ß1/Smad signal pathway and increase the expression of collagen â £. CA can decrease the occurrence of diabetic nephropathy(DN) by reducing the production of collagen â £ through inhibiting the TGF-ß1/Smad signal pathway.