Epithelial changes of the vas deferens after vasectomy and vasovasostomy in dogs.

Mucosal morphology of the vas deferens was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) after vasectomy and vasectomy reversal in dogs. Morphological changes occurred in the proximal (testicular) end of the vas deferens after vasectomy. Luminal dilatation, with an increase in 70% mean diameter, occurred due to build up of pressure. This resulted in flattening of the columnar cells, loss of stereocilia and presence of interspersed microvilli. The urethral portion of the vas deferens remained unchanged. Following vasovasostomy, reappearance of normal epithelial cells occurred through squamous metaplasia. Identical changes have also been observed after vasectomy in human vas deferens. It is fair to assume that similar recovery of the vasal mucosa may occur in humans after successful vasovasostomy.