Protective effects of geniposide against Tripterygium glycosides (TG)-induced liver injury and its mechanisms

Tripterygium glycosides (TG) are commonly used for basic medicine in curing rheumatoid arthritis but with a high incidence of liver injury. Geniposide (GP) has broad and diverse bioactivities, but until now it is still unknown whether GP can protect against TG-induced liver injury. This study, for the first time, observed the possible protection of GP against TG-induced liver injury in mice and its mechanisms underlying. Oral administration of TG (270 mg/kg) induced significant elevation in the levels of serum alanine / aspartate transaminase (ALT/AST), hepatic malondialdehyde (MDA) and pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) (all P < 0.01). On the other hand, remarkably decreased biomarkers, including hepatic glutathione (GSH) level, activities of glutathione transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), and anti-inflammatory cytokine interleukin (IL)-10, were observed following TG exposure (all P < 0.01). Nevertheless, all of these phenotypes were evidently reversed by pre-administration of GP for 7 continuous days. Further analysis showed that the mRNA expression of hepatic growth factor-beta1 (TGF-β1), one of tissue repair and regeneration cytokines, was enhanced by GP. Taken together, the current research suggests that GP protects against TG-induced liver injury in mice probably involved during attenuating oxidative stress and inflammation, and promoting tissue repair and regeneration.