TGF-β1-Sp1 signaling pathway regulates the expression of collagen I in guinea pig scleral fibroblasts

Background: TGF-β1(Transforming growth factor beta 1)has been shown to be involved in scleral remodeling in myopia; however, it is not fully clear how this pathway regulates collagen I expression.This aim to study the effect of TGF-β1-Sp1(specificity protein 1 )signaling pathway on the expression of collagen I in guinea pig scleral fibroblasts. Methods A primary cell culture was prepared from guinea pig scleral tissue. The obtained fibroblasts were divided into four groups, which were given the following treatments: no treatment, TGF-β1, TGF-β1 + Sp1 inhibitor, and TGF-β1 + TGF-β1 inhibitor. The mRNA and protein expression of collagen I and Sp1 was examined by immunohistochemistry, quantitative real-time PCR and western blotting. Results Compared with the control group, the protein and mRNA expression levels of Sp1 and collagen I were increased in the TGF-β1 group ( P  < 0.05), whereas they were decreased in the TGF-β1 + TGF-β1 inhibitor group ( P  < 0.05). The expression levels of these genes in the TGF-β1 + Sp1 inhibitor group were weaker than in the control, but stronger than those in the TGF-β1 + TGF-β1 inhibitor group ( P  < 0.05). Conclusions To a certain extent, TGF-β1 can mediate the expression of type I collagen through the Sp1 signaling pathway.