Experimental observation of pathological changes in the tissues after injurious biliary stricture / 中华肝胆外科杂志

ABSTRACT

ObjectiveTo explore the histopathological changes of bile duct,liver and local tissue for injurious biliary stricture(IBS). MethodTo observe the morphological and pathological changes of bile duct, local tissue and liver in different periods with dogs as the established animal model for IBS. ResultBile duct obstruction due to injury can expand the proximal bile duct up to 18.91 ±1.85 mm as the pressure goes up. Damage to local tissue triggers acute inflammation. In early injury phase (within 10 d), inflammatory cell infiltration and proliferation appears on the wall of the duct with increased mucosal edema as well as thickening of the biliary ductile wall. In the late injury phase (15 d), the degree of infiltration of inflammatory cells, edema and mucosal thickness were reduced whereas fibroblast and collagen tissue were proliferated extensively. The wall of biliary duct also becomes fibrotic and thickens. Quantitative analysis of the inflammatory edema shows the most severe outcome on the 5th day (HE staining WBC count of 54.2±5.8 unit) and its severity progressively subsides on the 15th day. (HE staining WBC count of 41.7±7.2 vs 54.2±5.8 a, P＜0.0,5). In the early obstruction (5 d and 10 d), the liver cells showed mild to moderate swelling and its degeneration is often associated with steatosis and sinusoidal expansion and congestion. As the obstruction time increases in the 20 d and 30 d group, liver cells starts to show extensive vacuolation and sinusoidal occlusion. ConclusionsEarly phase (5 days) of acute bile duct obstruction due to injury shows rapid expansion of the bile duct, edema in the bile duct itself as well as its surrounding tissue and liver damage. After 15 days, the local inflammatory edema is greatly reduced and is replaced by hyperplasia of fibers and collagen. Liver damage appears to be irreversible after 20 days. Considering local environmental and systemic conditions, the optimal time frame to repair obstruction of bile duct surgically is between 10-20 days.