Protective Effect Of Wedelolactone Against CCl₄-Induced Acute Liver Injury And Its Potential Mechanism In Mice

Objective: To study protective the effects of wedelolactone（WEL） against CCl₄-induced acute liver injury and the mechanism or the key molecular pathway of its liver protective.Methods: A total of 48 male C57BL/6 mice were randomly divided into six groups as follows:（Ⅰ） the control group: double distilled water（DDW） for 7 days;（Ⅱ） the WEL control group: WEL（220mg/Kg） for 7 days;（Ⅲ） the model group: DDW for 7 days then challenged with CCl₄;（Ⅳ） the CCl₄ plus WEL group: WEL（55mg/Kg） for 7 days then challenged with CCl₄;（Ⅴ） the CCl₄ plus WEL group: WEL（110mg/Kg） for 7 days then challenged with CCl₄;（Ⅵ） the CCl₄ plus WEL group: WEL（220mg/ Kg） for 7 days then challenged with CCl₄. WEL or DDW was administered orally once daily for 7 consecutive days. An hour after the last dose of WEL and DDW, CCl₄ was given by intraperitoneal injection. Mice were sacrificed 24 h after CCl₄ administration for collecting blood and liver tissues. Samples were used for the detection activities of serum alanine aminotransferase（ALT）, aspartate aminotransferase（AST）, glutathione peroxidase（GSH-Px） and Superoxide Dismutase（SOD）; levels of liver tissue Malondialdehyde（MDA）,tumor necrosis factor-α（TNF-α）, interleukin-1β（IL-1β） and interleukin-6（IL-6）; examinations of histopathology and immunohistochemical. Liver tissues proteins MAPKs（ERK, p-ERK,JNK, p-JNK, p38, p-p38）, Cox-2, iNOS, NF-kappa B, active caspase 3 levels were detected by western blot. Hepatocytes apoptosis were observed by TUNEL staining.Results:（1） Compared with model group, WEL could obviously decrease the liver enzymes ALT, AST activities in acute liver injury mice induced by CCl₄;（2） HE staining showed: WEL could significantly improve liver tissue pathological changes caused by CCl₄;（3） WEL could significantly enhance activities of superoxide dismutase（SOD）,glutathione peroxidase（GSH-Px） and lower the content of malondialdehyde（MDA）,showed good antioxidant effects;（4） Compared with model group, WEL-treatment significantly inhibited the up-regulation expression of TNF-α, IL-6, IL-1βand inflammatory protein Cox-2, iNOS caused by CCl₄ in liver tissue and had a dose dependent relationship;（5） Compared with model group, WEL-treatment groups could decrease thephosphorylation of ERK and the metastasis of NF-κB from cytoplasm to the nucleus,increase the phosphorylation of JNK, as well ashad a dose dependent relationship;（6） Apoptosis detection results showed that WEL treatment group apoptotic cells, the expression of Bax and active caspase 3 decreased significantly, the expression of Bcl-2increased significantly compared with model group, and had a dose dependent relationship.Conclusion:（1） WEL could obviously decrease elevated activities of ALT, AST in acute liver injury mice induced by CCl₄, improve liver pathological condition, reduce hepatocyte apoptosis and have protective effects against CCl₄-induced acute liver injury;（2） The protective effects of wedelolactone against CCl₄-induced acute liver injury were connected with its improvement of the ability to resist oxidative damage, inhibition of inflammation, regulation the expression of liver apoptosis protein;（3） The inhibition of inflammation possibly associated with the regulation of the phosphorylation of ERK, JNK and inhibition the metastasis of NF-κB from cytoplasm to the nucleus.