Expression of Transforming Growth Factor-β1/Smad Signaling Pathway in Rat Glomerular Mesangial Cell and Interventional Effects of Angiotensin-Converting Enzyme Inhibitor

Objective To investigate the role of transforming growth factor (TGF)-β1/Smad signaling pathway in glomerular mesangial cell (GMC), and the influence of angiotensin-converting enzyme inhibitor(ACEI) fosinopril (Fos) on the expression of phosphorylation-Smad2/3 (P-Smad2/3) and collagen Ⅰ(Col Ⅰ) in this way. Methods Glomerular mesangial cells of rat in vitro were cultured, and they were divided into 3 groups: ①TGF-β1 group (TGF-β1 5 ng/mL); ② Fos group (TGF-β1 5 ng/mL+ Fos 1×10-4 mol/L); ③control group (blank). Methyl thiazolyl tetrazolium (MTT) colorimetric method detected cellular proliferation. The change of phosphorylation-Smad2/3 expression was detected by indirect immunofluorescence. The expression of collagen Ⅰ in cell culture supernatant was detected by the enzyme-linked immunosorbent assay (ELISA). Results The optical density(OD) value of cellular proliferation was higher than that in TGF-β1 group when compared with control group(P<0.05), while lower in Fos group when compared with TGF-β1 group(P<0.05). Phosphorylation-Smad2/3 slightly expressed in control group, while increased obviously in TGF-β1 group compared with control group(P<0.05). In Fos group, the expression of phosphorylation-Smad2/3 were decreased apparently at 12 h and 24 h than those in TGF-β1 group(P<0.05). Conclusion TGF-β1 can activate the expression of phosphorylation-Smads and TGF-β1/Smad signaling pathway in glomerular mesangial cell, which will cause the increased expression of collagen Ⅰ and proliferation of glomerular mesangial cell. Fos can partially block the activation of transforming growth factor-β1/Smad signaling pathway in glomerular mesangial cell, inhibit the excretion of collagen Ⅰ and proliferation of glomerular mesangial cell. Key words: glomerular mesangial cell (GMC); collagen Ⅰ(Col Ⅰ); transforming growth factor-β1(TGF-β1); Smads; angiotensin-converting enzyme inhibitor (ACEI)