EFFECTS OF VASECTOMY ON THE EPIDIDYMIS

Common principles can be discerned in the response of the epididymis t o vasectomy, despite species differences. Increases in the size and nu mber of lysosomes are the most frequent changes in the epididymal epit helium. The presence or absence of additional alterations such as chan ges in the height of the epithelium may be related to variations in di stensibility of the vas deferens and epididymis. Direct measurements b y micropuncture of epididymal and seminiferous tubule hydrostatic pres sure indicate that, contrary to dogma, increased pressure in the dista l epididymis after vasectomy is not generally transmitted to the semin iferous tubules. The epididymal interstitium shows microscopic changes indicative of chronic inflammation, with infiltration of macrophages, lymphocytes, and plasma cells, and rats with these lesions have highe r antisperm antibody levels than animals lacking epididymal changes. M acrophages and neutrophils may enter the duct through the epididymal e pithelium, at sites of rupture of the duct, and in the efferent ductul es. Cyst-like spermatic granulomas occur in virtually all species wher e the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanic al properties of the tract in different species, and they are probably important in the immune response to vasectomy. Postvasectomy sera in Lewis rats recognize a consensus repertoire of dominant autoantigens t hat closely resembles the antigens bound by sera from rats immunized w ith isologous spermatozoa. There are multiple routes for disposal of t he sperm that continue to be produced after vasectomy. (C) 1995 Wiley- Liss, Inc.