Fine structure of the langur monkey vas deferens and possible role of changes following vasectomy in the success or failure of the vasovasostomy.

Studies on the ultrastructure of the vas deferens have been carried out in control, vasectomized (6 and 24 months) and vasovasostomized (12 months) langur monkeys (Presbytis entellus entellus Dufresne). Vas deferens epithelium of the control animals depicted four types of cells, viz. the basal cells, principal cells, mitochondria-rich or apical cells and pencil or dark cells. The basal cells were short, cuboidal in nature with prominent nuclei, and contained sparse cytoplasmic organelles. The principal cells were characterized by the presence of nuclei with irregular outline and intranuclear electron-dense granules, well-developed Golgi bodies with prominent secretory vesicles, cisternae of rough endoplasmic reticulum, mitochondria, free ribosome particles, lysosomes and stereocilia in the cytoplasm, suggesting an active secretory role, as well as the absorptive functions of the cells. The mitochondria-rich cells consisted of numerous mitochondria, and other cytoplasmic organelles were sparse. The pencil cells were dark, slightly compressed and situated between the principal cells. Vasectomy resulted in reduction of cytoplasmic volume and vacuolization of the cytoplasm, especially in the Golgi region of the principal cells. Rough endoplasmic reticulum and mitochondria were poorly defined. Vasovasostomy showed no appreciable improvement in the configuration of the cytoplasmic organelles. The results suggest that a persistent reduced secretory activity of the cells following vasectomy and vasovasostomy might also be one of the factors responsible for unsuccessful vasovasostomy.