Early ultrastructural changes in the rat testis after ductuli efferentes ligation

The early effects of ligation of the ductuli efferentes on testicular ultrastructure were studied in adult rats. As soon as 24 hours after the operation a large number of vacuoles appeared in the cytoplasm of Sertoli cells; vacuolization persisted for as long as 9 days, but localized in the apical part of the cells. Giant multinucleated cells containing annular clumps of chromatin were observed 1 day after ligation. The number of giant cells increased steadily as well as the alterations shown by their chromatin and cytoplasm. Isolated young spermatids also suffered morphologic changes that varied from almost normality to absolute necrosis. The thickness of the limiting membrane increased, as well as the number of cell layers. Deep infoldings, apparently caused by shrinkage of the tubules, were also noticed. Spermatogonias, spermatocytes I, mature spermatids, and spermatozoa did not present abnormalities. The interstitial tissue and the Leydig cells also appeared normal. It is concluded that ductuli efferentes ligation affects primarily the Sertoli cells; the formation of giant cells and the alterations shown by early spermatids and basement membrane are probably not specific but consequences of the injury to the Sertoli cells.