Anti-fibrotic Effect of Silibinin in Keloid Fibroblasts and a Bleomycin-induced, Scleroderma-like Animal Model

Ryu, Han Won; Kim, Sang Pyo; Cho, Jae We; Lee, Kyu Suk

Abstract

BACKGROUND
Silibinin reduces the expression of Type I collagen in normal skin fibroblasts through down-regulation of the TGF-beta/smad pathway. However, it is largely unknown whether silibinin can reduce the expression of Type I collagen in vivo sclerotic animal models, as well as in keloid fibroblasts.
OBJECTIVE
The purpose of this study was to investigate the effect of silibinin on the expressions of type I collagen, matrix metalloproteinase-1 (MMP-1), MMP-2, smad2/3, and TGF-b1 receptor in keloid fibroblasts in vitro, and to evaluate the anti-fibrotic effect of silibinin in a bleomycin-induced, scleroderma-like animal model in vivo.
METHODS
Keloid and normal skin fibroblasts were treated with silibinin (20~100 mM), and the expressions of type I collagen, MMP-1, MMP-2, and TGF-b1 receptor were analyzed with western blot. The animal model was established by bleomycin treatment (1.0 mg/mL) for 2 weeks in C57/BL9 mice. Then silibinin was injected on one side of the back and the same volume of normal saline was injected on the other side of the back. The specimen was evaluated with H&E, Masson-trichrome, and TGF-beta1 immunohistochemical staining.
RESULTS
Expressions of Type I collagen, MMP-1, and MMP-2 decreased, but the expression of TGF-beta1 receptor increased in keloid fibroblasts after silibinin treatment. Thickened dermis with dense extracellular matrix and inflammatory cell infiltration of the bleomycin-induced, scleroderma-like animal model improved after silibinin treatment. Expression of TGF-beta1 decreased after silibinin treatment in the bleomycin-induced, scleroderma-like animal model.
CONCLUSION
Silibinin treatment decreased the expression of Type I collagen in keloid fibroblasts in vitro. In addition, silibinin decreased the expression of Type I collagen by inhibiting TGF-beta1 expression in the bleomycin-induced, scleroderma-like animal model. These results indicate that silibinin has the potential to be an effective antifibrotic agent.