Ultrastructure of langur monkey epididymidis prior to and following vasectomy and vasovasostomy

The ultrastructural changes in langur monkey epididymis prior to and follow ing vasectomy or vasovasostomy were studied. The epididymal epithelium of t he intact langur monkey was found to consist mainly of principal cells and basal cells and frequently apical or mitochondria rich cells were found. Be sides these cells intraepithelial lymphocytes were also a consistent featur e of the epididymal epithelium. Principal cells identified by means of the tuft of the stereocilia on their apical surface, bear well developed Golgi bodies, endoplasmic reticulum, vesicles, vacuoles and multivesicular bodies . This suggests their active involvement in absorption and secretion. Basal cells present at the base of the lamina bear a few cellular organelles and strong interdigitations with the adjacent cells. Apical or mitochondria ri ch cells were characterized by clusters of mitochondria in the apical regio n of the cell and few microvilli on their apical surface. Lymphocytes with a large nucleus and a pale rim of cytoplasm were also found at the base of the epithelium. Secretory and absorptive functions of principal cells of th e epididymal epithelium were found to be increased after vasectomy, as indi cated by bulging of the apical portion of the principal cells and membrane bound structure in the lumen. An extensive increase in the number of lysoso mes, vesicles and vacuoles was also observed. An increase in the number of macrophages with spermatozoa remnants in the lumen of epididymis suggests t hat the principal mechanism for spermatozoa disposal following vasectomy is intraluminal endocytosis by macrophages. Changes following vasectomy persi sted in vasovasostomized animals even after 12 months of recanalization, wh ich may contribute to the failure of functional reanastomosis.