[Effects of experimental vasectomy on testicular structure: ultrastructural study]

We have performed experimental vasectomies in dogs in order to study effects of vas deferens ligature with close technique, on the testicular ultrastructure. We point out the existence of alterations: structural changes of the seminiferous epithelium, great extracellular spaces which are generated for the premature exfoliation of germinal cells, degeneration of the germinal shock cells, the appearance of immature germinal cells and multinucleate spermatids in every stages of the spermatogenesis, the fall of mature spermatozoid number, thickening of basal membrane, relative increase in the Sertoli's cells size as well as their phagocytic function, and existence of spermaphagos unfasted into tubular lumen. The Leydig's interstitial islets show an absolutely normal cellular and vascular configuration.