Dandelion polyphenols protect against acetaminophen-induced hepatotoxicity in mice via activation of the Nrf-2/HO-1 pathway and inhibition of the JNK signaling pathway

摘要

We investigated the liver protective activity of dandelion polyphenols(DP)against acetaminophen(APAP;Paracetamol)-induced hepatotoxicity.Mice were acclimated for 1 week and randomly divided into the following groups(n=9 per group):Control,APAP,APAP+DP(100 mg·kg^–1),APAP+DP(200 mg·kg^–1),and APAP+DP(400 mg·kg^–1)groups.Mice were pretreated with DP(100,200,and 400 mg·kg^–1)by oral gavage for 7 d before being treated with 350 mg·kg^–1 APAP for 24 h to induced hepatotoxicity.Severe liver injury was observed,and hepatotoxicity was analyzed after 24 h by evaluation of biochemical markers,protein expressions levels,and liver histopathology.Pretreatment with DP was able to restore serum liver characteristics(aspartate transaminase,AST;alanine aminotransferase,ALT;alkaline phosphatase,AKP),improve redox imbalance(superoxide dismutase,SOD;glutathione,GSH;malondialdehyde,MDA),and decrease inflammatory factors(tumor necrosis factor-α,TNF-α;interleukin-1β,IL-1β).Pretreatment with DP also significantly inhibited the expression levels of nitric oxide synthase(iNOS)and cyclooxygenase-2(COX-2).Furthermore,DP pretreatment could inhibit the apoptosis of liver cells caused by APAP through up-regulation of Bcl-2 and down-regulation of Bax and caspase-9 protein.DP also down-regulated p-JNK protein expression levels to inhibit APAP-induced mitochondrial oxidative stress and up-regulated the expression of Nrf-2 and its target gene HO-1.The histopathological staining demonstrated that DP pretreatment could inhibit APAP-induced hepatocyte infiltration,congestion,and necrosis.Our results demonstrate that DP pretreatment could protect against APAP-induced hepatic injury by activating the Nrf-2/HO-1 pathway and inhibition of the intrinsic apoptosis pathway.