SIRT1/IGFBPrP1/TGF β1 axis involved in cucurbitacin B ameliorating concanavalin A-induced mice liver fibrosis

The present study investigated the improving effect of cucurbitacin B on liver fibrosis induced by concanavalin A in mice and explored its possible mechanism. AST, ALT and TB were detected by kits. ELISA was performed to detect the levels of IL 5, IL 6, IL 13 and TNF-alpha in serum. Haematoxylin-eosin (HE) staining and Masson's trichrome staining were used to evaluate pathological changes. Western blotting was performed to observe expression levels of sirtuin (SIRT) 1, insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) and TGF beta 1. The activity of SIRT 1 also was detected. Results showed that cucurbitacin B could effectively improve the abnormal liver function, inhibit liver fibrosis and suppress releases of inflammatory factors in mice induced by concanavalin A. Furthermore, cucurbitacin B could down-regulate the expressions of TGF beta 1 and IGFBPrP1, increase the expression and activity of SIRT 1. Interestingly, when SIRT1 activity was inhibited by EX 527, a selective inhibitor of SIRT 1, the preventive effect of cucurbitacin B was significantly attenuated. Taken together, the above results showed that cucurbitacin B could significantly suppress releases of inflammatory cytokines and improve liver fibrosis induced by concanavalin A in mice, and those may be achieved through SIRT1/IGFBPrP1/TGF beta 1 axis.