Histochemical Study of Heparin-positive Mast Cells in the Terminal Part of Porcine Ductus Choledochus and Papilla Duodeni Major

Summary The study presented in detail the localization and density of mast cells (MCs) in the intramural part of the common bile duct (CBD) and in the major duodenal papilla (MDP) of domestic swine. MCs' density (number/mm2) in different layers of both of the duct and papilla was evaluated after toluidine blue staining. Their number was higher in the lamina propria mucosae than in the tunica muscularis of the studied structures. The localization of berberine-positive, (heparin containing) MCs and the ratio between them and toluidine blue-positive MCs with γ-ma metachromasia was also established. Ratios of heparin-containing MCs in comparison with all toluidine blue-positive MCs were found as follows: ductus choledochus – 32% in the subglandular connective tissue of lamina propria mucosae in the intramural part of the duct; m. sphincter ductus choledochus – 31% in the circular and 0.06% in the longitudinal muscle layer; subserosa – 59%; papilla duodeni major – 0.03% in the subepithelial connective tissue and 34% in the subglandular connective tissue of lamina propria mucosae, respectively. The established large difference in heparin-positive MCs in both the subepithelial and subglandular connective tissues of CBD and MDP, respectively, is an evidence for the existence of mucosal and connective tissue MCs.