Yu Gan Long reduces rat liver fibrosis by blocking TGF-β1/Smad pathway and modulating the immunity

Abstract Yu Gan Long (YGL) is a Chinese traditional herbal medicine that has been used in the treatment of liver fibrosis for many years in clinical practice. However, its anti-hepatofibrotic mechanism has not been studied yet. In this study, the effect and mechanism of YGL in reducing liver fibrosis was demonstrated in vivo . Our results showed that liver fibrosis biomarkers collagen IV (Col IV), type III precollagen (PCIII), hyaluronuc acid (HA) and laminin (LN), were increased after CCl 4 treatment and decreased by YGL. Among the liver fibrosis indicators, α-smooth muscle actin (α-SMA) was decreased by YGL in the CCl 4 -treated rats, while MMP2 and MMP9 was upregulated followed by TIMP1 downregulation. Proteins involved in liver fibrosis such as p-Smad2, p-Smad3 and Smad4 were down-regulated, while Smad7 protein was up-regulated by YGL after CCl 4 -induced liver damage. YGL also suppressed the increase of TGF-β1, TNF-α, IL-1β, IL-6, IL-4 and IL-17 A induced by CCl 4 treatment, while promoted IFN-γ expression. Finally, the transcription factors ROR-γt and GATA3 were decreased, while T-bet was increased after YGL treatment. These results suggested that YGL attenuated CCl 4 -induced hepatic fibrosis by accelerating the extracellular matrix degradation, blocking the TGF-β1/Smad signaling pathway and modulating the balance among IL-4, IL-17 A and IFN-γ, demonstrating YGL protective effect and its potential mechanisms in treating liver fibrosis.