Influence of rapamycin and chloroquine on chemically-induced liver injury in rats

Drug-induced liver injury is a major reason for the discontinuation of drug development. Autophagy is a self-digestive process in the cell and can suppress cell death by removing damaged organelle from the cell. It is known that autophagy can modify drug-induced liver injury; however, details of the effects of autophagy modulation on chemically-induced hepatotoxicity are unclear. In this study, we investigated the influence of autophagy induction by rapamycin or inhibition by chloroquine on carbon tetrachloride (CCl₄)- or allyl alcohol (AA)-induced acute liver injury. Ten- to eleven-week-old male F344 rats were administrated with CCl₄ or AA after pretreatment by rapamycin or chloroquine, and were sampled 18 hours after the hepatotoxicant administration. Hepatic expression of the autophagosomal membrane protein LC3-II was significantly suppressed after CCl₄ administration by rapamycin pretreatment, compared with that in vehicle (DMSO) pretreatment. Expression of autophagy cargo protein p62, were significantly decreased after rapamycin treatment with AA administration. Hepatic p62 expression increased by chloroquine pretreatment. Serum AST and ALT were decreased after CCl₄ exposure in both rapamycin- and chloroquine-pretreated rats. On the other hand, regardless of pretreatment, pathological changes were mild in rats with AA exposure. These results showed that pretreatment with rapamycin or chloroquine can attenuate CCl₄-induced acute liver injury in rats.