Betulinic Acid Improved Hepatic Fibrosis Process Based On Modulating STAT3 Signal Pathway

Objective:In this study, the protective effects and underlying mechanisms of Betulinic acid (BA) were examined against hepatic fibrosis in vitro.Methods:First, we collected the medium of RAW264.7 stimulated with LPS (1μg/ml) for 0-12 hours and detected the level of IL-6 by ELISA. Second, HSCs were pretreated with BA (0-25μM) for 2 hours prior to the incubation of medium which RAW264.7 stimulated with LPS 12 hours for indicated time. Third, we investigated the expression of a-SMA, Collagen-1, MMP-13, TIMP-1, p-STAT3, STAT3, TLR4, CD14, p-AMPK, AMPK, p-LKB1, LKB1 by western blotting at protein level. We obtained the best time for subsequent experiments by analyzing the data. Then, HSCs were pretreated with indicate concentrations of BA for 2 hours prior to 1h. At last, we examined the expression of the same protein.Results:First, the concertration of IL-6 in the medium of RAW264.7 increased in time-dependent after LPS pretreated 0-12 hours, increased significantly after 6h and the level of IL-6 which pretreated 12h increased significantly compared to previous groups. Second, the results showed BA decreased the level of a-SMA of activated HSCs in time-dependent and dose-dependent. Meanwhile, BA increased the ratio of MMP-13 and TIMP-1. BA also activated phosphorylation of STAT3 incubation of medium, decreased the level of TLR4 and CD 14 and increased phosphorylation of AMPK.Conclusion:BA administration significantly activated phosphorylation of STAT3 and regulated the progress of hepatic fibrosis. The underlying mechanisms may be inhibition of TLR4 and activation of phosphorylation of MAPK. Therefore, BA may be considered as a potential therapies candidate for hepatic fibrosis.