Effects of Smad3 Inhibited on expression of collagen I in c2c12 cells induced by TGF-β1

【Objective】To investigate the effects of RNA interference blocking Smad3 gene expression on collagen type I expressions induced by TGF-β1.【Methods】The expressions of collagen type 1 secreted by C2C12 cells were measured with ELISA and RT-PCR methods separately after interfered with different concentration of TGF-β1 (0, 1, 5 and 10 ng/mL) for 24 hours. And the C2C12 cells were treated with siRNA in vitro. Proteins and mRNA expressions of collagen type 1 were measured too.【Results】After C2C12 cells were treated with 0, 1, 5 and 10 ng/mL TGF-β1 for 24 hours, the expression of the collagen type 1 (ng/mL) with ELISA were (616±16), (713±19), (783±23), (853±17), and RT-PCR (photo density value ratio for collagen type 1/β-actin) were (0.93±0.08), (1.83±0.17), (2.50± 0.29), (2.94±0.14) respectively, all P 0.01. After tranfected C2C12 with 200 pmol/L siRNA-Smad3 for 24 hours, then 5 ng/mL TGF-β1 was treated for 24 hours, the CICP values of collagen type 1 measured with ELISA for experimental group, blank control group and internal control group were (413±20), (473±29), and (571±29) ng/mL respectively, and the relatively values of collagen type 1 measured with RT-PCR were (0.78±0.17), (0.86±0.10) and (1.85± 0.19) separately, the value in internal control group is higher (vs experimental group, P 0.05).【Conclusions】TGFβ1 enhance collagen type 1 protein synthesis and mRNA expression in C2C12 cells with a dose-dependent manner, which could be inhibited by siRNA-Smad3. SiRNA inhibit the expression of Smad3 and the function which enhance the synthesis of collagen type I and mRNA expression by TGF-β1.