Abstract:Objective:To investigate the myocardial injury induced by bile duct obstruction and the protective effects ulinastatin(UTI). Methods:Dynamic observation of of the levels of malondialdyhyde(MDA) and superoxide dismutase（SOD） of myocardial tissues, and the levels of serum TBil, alkaline phosphatase(ALP), MB isoenzyme of creatine kinase(CK-MB), endotoxin (ET), and tumor necrosis factor(TNF-α) in bile duct obstruction(BLD) rats and UIT treatment rats. The left ventricles of the rats were obtained for light and electronic microscopic observation. Immunohistochemical staining method of ABC used was to locate the expression and distribution of TNF-α in myocardial tissues. Results:After ligation of the common bile duct, serum TBIL, ALP, CK-MB, ET, TNF-α levels and myocardium MDA gradully increased, while SOD levels gradually decreased, and the expression of TNF-α in myocardium increased. As compared with BDL group at the same phase, in UIT group, serum TBIL, ALP, CK-MB, ET, TNFα levels and myocardium MDA in UTI-treated groups decreased, while myocardium SOD increased, and the expression of TNF-α in myocardium decreased．Myocardial injuries of bile duct obstruction were aggravated as time progressed, and there were less myocardial injuries in UTI-treated groups than in BDL groups at the same stage as shown with light and electronic microscopic observation．Conclusions:UTI can effectively protect the myocardium from ET,TNF-α and free radical injury in bile duct obstucion rats.