Studies on the pathology of dicrocoeliasis and fascioliasis in the goat. II. The histochemistry of bile-duct mucosubstances

Histochemical studies were made on the characteristics of carbohydrate-rich compounds in the bile-duct mucosa of goats infected either with Dicrocoelium dendriticum or with Fasciola hepatica. In a previous study the author showed that a chronic infection with these parasites produces glandular hyperplasia in the walls of bile ducts. This study revealed a definitely increased secretion of qualitatively normal mucosubstances by the hyperplastic epithelial cells.Epithelial mucosubstances in the bile-duct walls were characterized by the presence of periodate-reactive hydroxy groups and both carboxyl and sulphate radicals. The intensity of the PAS reaction was moderate or strong and not definitely inhibited by the acidic or acetyl radicals. Specific enzymatic digestions did not reveal periodate-reactivity produced by glycogen or basophilia due to hyaluronic acid or chondroitin-4 and -6-sulphates in the epithelial cells. On the other hand, sialidase digestion showed that the main part of the carboxymucins was sialidase-labile sialomucins. Their susceptibility towards sialidase was not definitely increased after deacetylation. The single and sequential histochemical methods showed a more intense staining reaction for sulphate radicals in the mucosubstances of the deep glandular and goblet cells than in those of the superficial glands, which were characterized by high concentration of carboxyl groups.Keyword: Dicrocoelium dendriticum, Fasciola hepatica, liver, bile ducts, mucosubstances