Dexamethasone Effect on the Expression of Transforming Growth Factor-β1/Smads Signaling Pathway in Benign Biliary Stricture Fibroblasts in Rodent.

OBJECTIVE: To investigate the effects of dexamethasone on transforming growth factor (TGF)-β1/Smads signaling pathway in benign biliary stricture (BBS) fibroblasts.

STUDY DESIGN: An experimental study.

PLACE AND DURATION OF STUDY: Guizhou Medical University, Guiyang, Guizhou, China, from January to August 2016.

METHODOLOGY: Fibroblasts derived from rabbit BBS model were cultured and identified, then treated by different concentration of dexamethasone (0.02, 0.1 and 0.5 mg/ml). Dexamethasone-treated cells and non-treated control groups were incubated respectively for 48 hours. Cell proliferation was assessed using cell counting kit-8. Relative mRNA expression of TGF-β1, Smad4 and Smad7 were assessed by quantitative RT-PCR. Protein expression of TGF-β1 and Smad4 were investigated by Western blotting.

RESULTS: Treatment with dexamethasone significantly inhibited the proliferation of BBS fibroblasts, significantly attenuated both the mRNA and protein expression of TGF-β1 and Smad4, and significantly up-regulated the mRNA expression of Smad7 in BBS fibroblasts (all p<0.05, 0.1-0.5 mg/ml), and exhibited in a dose-dependent manner.

CONCLUSION: TGF-β1/Smads signaling pathway may play an important role in BBS progression; dexamethasone significantly altered the expression of TGF-β1/Smads signaling pathway and significantly inhibited cell proliferation in rabbit BBS fibroblasts. Therefore, dexamethasone may be a therapeutic option for the prevention of BBS.