Appearance of Peculiar Multivesicular Bodies in the Principal Cells of the Epididymal Duct after Efferent Duct Cutting in the Mouse

Abstract

Ligation of the efferent duct in the mouse results in appearance of PAS-positive inclusions in principal cells in the duct of the epididymal body, and the inclusions are considered to be formed by absorption of the luminal PAS-positive material produced in the epididymal head (ABE et al., 1982a). For better understanding of the significance of the inclusions, this study examined morphologic changes in the principal cells after efferent duct cutting, by light and electron microscopy.
Electron microscopy revealed that the principal cells containing PAS-positive inclusions are characterized by a nipple-like protrusion—micropapilla—on the luminal surface and by peculiar multivesicular bodies in the supranuclear cytoplasm. The micropapilla, 1-2μm in height, contains ductules of 0.2-0.5μm thickness which extend from its tip to the multivesicular bodies. The multivesicular bodies, measuring up to 10μm in diameter, are larger toward the nucleus. They contain numerous vesicles, 40-100nm in diameter, and an amorphous material that is similar to the luminal material of the epididymal duct. In addition, larger multivesicular bodies are heterogenous in structure and possess bundles of tubules 40nm thick. There are dense bodies in the basal cytoplasm under the nucleus which appear to be transformed from the multivesicular bodies.
In summary, occurrence of the micropapilla and the giant multivesicular bodies are considered to represent an activated breakdown of the material ingested from the duct lumen.