Abstract: Objective: To investigate the role of tumor necrosis factor-α(TNF-α) in liver damage in rats with obstructive jaundice and the protective effect of anti-TNF-αMcAb.Methods: Twenty-four male Sprague-Dawley rats were randomly divided into three groups:bile duct-ligation(BDL) group,bile duct-ligation+anti-TNF-αMcAb(BDL+anti-TNF-αMcAb) group and sham-operation(SO) group.BDL+anti-TNF-αMcAb group was subjected to damage with intravenous administration of anti-TNF-αMcAb(1mg/kg) for five days,starting from the 3rd day after bile duct-ligation;BDL group and SO group were administered with saline in the same manner.The levels of serum alanine amiotransferase(ALT),aspartate aminotransferase(AST) and TNF-α were detected in each group.The histopathology was observed by light and electron microscopy in the liver of rats with obstructive jaundice.Results: The levels of serum ALT,AST and TNF-α in BDL group and BDL+anti-TNF-αMcAb group were markedly higher than those in SO group(P<0.01),and the levels of serum ALT,AST and TNF-α in BDL+anti-TNF-αMcAb group were much lower than those in BDL group(P<0.05 to P<0.01),the changes of liver histopathology were minor in BDL+anti-TNF-αMcAb group.SO group had no apparent change.Conclusions: TNF-α may be one of the most important mediators in live damage induced by obstructive jaundice,and the use of anti-TNF-αMcAb can relieve the liver damage.