Isoliquiritigenin protects against triptolide-induced hepatotoxicity in mice through Nrf2 activation.

Isoliquiritigenin, a flavonoid found in licorice, has been considered as an antioxidive and hepato-protective agent. Recent studies have shown that a possible mechanism for triptolide-induced hepatotoxicity is related to oxidative damage induced by reactive oxygen species. This study was done to investigate the protection effect of isoliquiritigenin against triptolide-induced hepatotoxicity and the mechanism involved. An acute liver injury model was established by intraperitoneal injection of triptolide (1.0 mg · kg-1) in mice. Different doses of isoliquiritigenin (12.5, 25 and 50 mg · kg-1) were employed as protection. The activities of AST, ALT, ALP and LDH in serum and levels of GSH, GPx, SOD, CAT and MDA in liver tissue were detected. The histopathological changes of liver tissues were observed after HE staining. The protein expression of Nrf2 was detected by western blot. Pretreatment with isoliquiritigenin significantly prevented the triptolide-induced hepatotoxicity indicated by reduced activities of AST, ALT, ALP and LDH. Moreover, isoliquiritigenin pretreatment also prevented from triptolide-induced hepatotoxicity by inhibiting MDA and restoring the levels of GSH, GPx, SOD and CAT. In addition, isoliquiritigenin could attenuate histopathological changes induced by triptolide. Furthermore, the results indicated that isoliquiritigenin pretreatment caused an increase in the protein expression of Nrf2. These results indicated that isoliquiritigenin could protect against triptolide-induced hepatotoxicity via activation of the Nrf2 pathway.