Differences in hepatic pathology resulting from bile duct obstruction in young and old rats

1. Young and adult rats subjected to complete bile duct ligation from 4 to 40 days revealed different liver histopathologies at the end of the experimental period. 2. In young rats, ductal and ductular proliferation resulted in septal fibrosis which, originating from the portal spaces, tended to delimit areas of nodular parenchymal transformation (secondary biliary cirrhosis). In adult rats, proliferating ductal and ductular structures diffusely invaded the hepatic parenchyma, dissociating the liver cell plates in a pattern similar to that of a malignant neoplastic growth. 3. The different result of the lesions in young and old rats suggests that an age-related factor may be involved in the pathogenesis of lesions resulting from biliary obstruction.