Research Of Liver Function And Local Pathological Changes In Obstructive Injury Of Bile Duct In Dogs

Objective: To explore the change of hepatic function and the local pathology in the bile duct injury of dog in different periods of obstructive extrahepatic bile duct injury by stablishing the animal model of the obstructive bile duct trauma. Reveal the operation timing in obstructive bile duct injury.Methods : The models of obstructive jaundice were established by bile duct ligation(BDL) in36 dogs. The 36 dogs were randomly divided into BDL0 (0day of bile duct ligation n=6), BDL5 (n=6), BDL10(n=6), BDL15(n=6), BDL20(n=6) and BDL30(n=6). The common bile duct diameter, pressure and liver function indicators were measured and the pathomorphological changes of liver were observed in each group. The obstructive section of the bile duct was extracted separately at 6 time phases after producing the obstructive jaundice at 0,5,10,15,20,30d. meanwhile, degree of bile duct wall inflammation and dropsy were observed by HE stain . The expression intensity of transforming growth factor-β1(TGF-β1),macrophage(MΦ) andα-smooth muscle actin (α-SMA) at different time phases after bile duct injury were also examined by immunohistochemistry.Results: With the extension of time with the common bile duct ligation, the level of common bile duct pressure was the highest after 5 days. The continued expansion in bile duct diameter of the obstruction period, the bile duct diameters in 30d are about 10 times higher than the control. By liver function and pathology HE staining, the cloudy swelling degeneration of hepatocyte of the treated groups were observered in early period (BDL5) , liver cell damage increased along with time in the treated groups. The cells of the liver showed widespread hyaline degeneration 15 days after ligation. In the situation of common bile duct being obstructed completely, The inflammation and edema of gall bladder wall is obvious in early(BDL5,BDL10)bile duct injury, however, innflammation and edema of gall bladder wall reduced in the latter(BDL20,BDL30) of bile duct injury and Scattered collagen fibers were fount in the bile duct wall. In the period of bile duct obstruction, the TGF-β1,MΦandα-SMA expression increased in the bile duct, the difference was statistically significant compared with the control group (P<0.05), And both gradually increased with the extension of obstruction time.Conlusion:The obstructive bile duct injury in dogs can lead to rapid increase in pressure, the continued expansion of bile duct and progressive liver damage,and cause a severe edema and inflammatory infiltration in the bile duct wall in the early obstruction,but alleviate in the late obstruction,meanwhile,found excessive proliferation of collagen fibers.At the same time,the obstructive bile duct injury in dogs promote the expression MΦ, TGF-β1andα-SMA increased continuously in the bile duct tissues.