An Experimental Study On Microvessel Density On Varied Levels Of The Injured Extrahepatic Bile Duct

Objective To explore the distribution of extraheptic bile duct microvessel density (MVD) under physiological and injured conditions with the purpose of getting to know whether there exists physiological uneven distribution of extrahepatic bile duct MVD and whether this uneven distribution would lead to a regional difference of ischemia following bile duct injury (BDI).Methods Twenty-five Beagle dogs were randomly divided into normal control group, BDI group, BDI-repair group.The animal model is built in accordance with Davidoff 'typical' model of bile duct injury happened in the laparoscopic cholecystectomy. On the fifteenth day after model building, animals were sacrificed with their bile duct tissue being excised for pathological study. The microvessel density marked with CD34 of bile duct tissue is examined using Weidner's method of immunohistochemistry with Max Vision methed, averages of each level are compared. Living condition and mortality rate of animals in each group were observed and recorded as well.Results Physiological extrahepatic bile duct MVD reads level a> level b> level c (P<0.05); after establishment of injury-restore model, extrahepatic bile duct MVD reads level a> level b> level c (P<0.05). Comparing injury-restore group with normal control group and injury group, level a of normal control group with higher MVD before injury-restore operation was remarkably decreased after the operation (P<0.05). Conclusions Extrahepatic bile duct MVD is not physiologically well distributed. There is a relation between the density and the distance from hilar. The nearer, the denser. When LC-BDI occurs, MVD on varied levels of the Extrahepatic Bile Duct was less than that on normal control group.The nearer with injury-position, the denser.A common extrahepatic bile duct ischemia appears, with a distinct lowering of the MVD. However, there seems to be a regional difference in extent concerning ischemia. The change of difference is internally related to the physiological uneven distribution of MVD. That is, the 'sparse area' of microvessel under physiological condition tends to turn into a 'disaster area' of bile duct ischemia after the occurrence of LC-BDI.