Protective Effect Of Apigenin On Alcohol-induced Liver Injury And Its Possible Mechanisms

Aim:To examine the protective effect of apigenin on alcohol-induced liver injury and investigate the potential mechanisms.Methods:In vivo,Kunming male mice were randomly divided into the control group,model group,apigenin 150 and 300 mg/kg groups,and gluthion 240 mg/kg group.The experimental mice were given 56°Redstar erguotou wine or simultaneously given apigenin150-300 mg/kg by gavage for 30 days.Finally,all the mice were sacrificed,the levels of serum alanine aminotransferase（ALT）and aspartate aminotransferase（AST）,hepatic reduced glutathione（GSH）,glutathione reductase（GR）,glutathione peroxidase（GSH-PX）,glutathione-S-transferase（GST）,malondialdehyde（MDA）,alcohol dehydrogenase（ADH）,acetaldehyde dehydrogenase（ALDH）,and tumor necrosis factor-alpha（TNF-α）were determined.The coefficient of liver weight was calculated and the hepatic histopathological changes were examined under a light microscope.The expressions of hepatic peroxisome proliferator-activated receptor（PPAR）α/γ,sterol regulatory element binding protein-1c（SREBP-1c）,fatty acid synthase（FAS）,diacylglycerol acyltransferase（DGAT）,carnitine palmitoyltransferase-1（CPT-1）,cytochrome P450 2E1（CYP2E1）,and nuclear factor kappa B（NF-κB）proteins were determined by Western Blot methods,respectively.In vitro,the rat BRL hepatocytes were used to observe the effects of apigenin on ethanol-or its toxic metabolite acetaldehyde-and hydrogen peroxide（H₂O₂）-induced hepatocellular injury as well as lipopolysaccharide（LPS）-induced inflammatory cytokine production.In the acetaldehyde-treated cells,the levels of the supernatant ALT and ALDH were determined.In the H₂O₂-treated cells,the levels of the supernatant MDA and superoxide dismutase（SOD）were determined.In the ethanol-treated cells,CYP2E1inducer isoniazid-treated cells,ethanol plus isoniazid-treated cells,and ethanol plus GR inhibitor carmustine-treated cells,the levels of the supernatant ALT and MDA as well as the intracellular GSH,GR,GSH-PX,GST,and CYP2E1 were determined.In the LPS-treated cells,the levels of the supernatant TNF-αand interleukin-6（IL-6）as well as the expressions of the intracellular NF-κB and IκB-αproteins were determined.Results:In vivo,the results showed that after treatment with apigenin150-300 mg/kg30 days,the coefficient of liver weight and serum AST level were decreased,especially in the 300 mg/kg group（p<0.05 or p<0.01）.Also,the levels of hepatic ADH and TNF-αwere decreased（p<0.05 or p<0.01）.Inversely,the levels of hepatic GR,GSH-PX,GST,and ALDH were increased（p<0.05 or p<0.01）.Furthermore,the histological evaluation of liver specimens demonstrated that the degree of hepatic steatosis in apigenin-treated groups was ameliorated.The Western Blot assays showed that apigenin could significantly up-regulate the expressions of hepatic PPARα/γand CPT-1A proteins（p<0.01）,and down-regulate the expressions of hepatic SREBP-1c,FAS,DGAT,CYP2E1,and NF-κB proteins（p<0.01）.In vitro,the results showed that following pretreatment of cells with apigenin,the levels of supernatant ALT,MDA,TNF-α,and IL-6 as well as the expressions of hepatocellular CYP2E1 and NF-κB proteins were significantly reduced（p<0.05 or p<0.01）,while the levels of hepatocellular GR,GSH-PX,SOD,and ALDH as well as IκB-αprotein expression were significantly increased（p<0.05 or p<0.01）.Conclusion:The present results demonstrated that apigenin might exert a protective effect on alcohol-induced liver injury,and its mechanisms might be related to the acceleration of ethanol metabolite acetaldehyde degradation,improvement of PPARα-mediated lipid metabolism pathway,and inhibition of CYP2E1 expression and enhancement of antioxidant ability.The latter and PPARγmight synergically decrease the ROS-mediated NF-κB activation and inflammatory cytokine production.