The epididymides of Lewis rats were studied at intervals up to 7 months after vasectomy, vasectomy followed 3 months later by vasovasostomy, or sham operations. Epididymal histology was related to testicular alterations and to serum antisperm antibodies as determined with an enzyme-linked immunosorbent assay. In vasectomy and vasovasostomy groups. 13 of 33 rats had testicular alterations, which consisted mainly of pronounced depletion of germ cells. Over half of the rats with testicular alterations also had severe epididymal lesions that included interstitial changes characteristic of an inflammatory response. These consisted of aggregates of mononuclear cells, including lymphocytes, plasma cells, and macrophages. The lumina of epididymides with interstitial changes contained polymorphonuclear leukocytes and/or macrophages. All animals with altered testes had greatly decreased numbers of epididymal sperm. In many instances, the lumen of the proximal cauda epididymidis was collapsed, and columnar cells of the epididymal epithelium contained many very large lysosomes. The distal cauda epididymidis was distended with sperm and debris. None of the rats that lacked testicular alterations showed epididymal changes. Mean serum antisperm antibody levels were significantly higher for rats with epididymal interstitial changes than for animals without such epididymal alterations. Infiltrations of inflammatory cells into the epididymal interstitium and lumen are part of the constellation of changes that occurs after immunization with testicular homogenates to produce experimental allergic orchitis. The observations reported here support the hypothesis that reproductive tract alterations after vasectomy in this model have an immune basis.

Although there is a consensus that very early orchiopexy is advantageous, there is little experimental data to support this view. Therefore, we studied early pre-pubertal versus later pre-pubertal orchiopexy in a cryptorchid rabbit model. Male offspring were divided into four groups with six to nine rabbits in each group: 1) controls (CON); 2) shams undergoing sham operations at both three weeks and two months of life (SHAM); 3) cryptorchid on day 3 with orchiopexy at three weeks and sham operation at two months (O3W); 4) cryptorchid on day 3 with sham operation at three weeks and orchiopexy at two months (02M). All animals were sacrificed post-puberty at six months of age; the tests were fixed in situ by perfusion fixation, embedded in glycol methacrylate, and underwent morphometric analysis in a blinded fashion. The average seminiferous tubular diameter (STD) of the CON, SHAM, O3W, and O2M groups was 234, 160, 116, and 123 microns, respectively. The average testicular biopsy score count (TBSC) of the CON, SHAM, O3W and O2M groups was 9.0, 5.2, 3.5 and 3.5, respectively. There is no significant difference in STD or TBSC between the O3W and O2M cryptorchid groups, and values for both of these groups were significantly different from those of the SHAM group. In addition, a significant effect of sham operation was demonstrated. These results demonstrate no advantage of very early orchiopexy in this model, and are consistent with the clinical literature which, in general, shows reduced reproductive potential of a cryptorchid testis after orchiopexy.

The relationship between alterations in testicular histology and antisperm antibodies was studied after vasectomy and vasovasostomy in Sprague-Dawley rats, which are immunologically relatively non-responsive to vasectomy. Testes were prepared for histologic study at intervals up to seven months after vasectomy, vasectomy followed three months later by vasovasostomy, or sham operations. Antisperm antibodies were assessed with an ELISA. Testicular alterations, which were observed in a minority of animals after vasovasostomy, consisted mainly of depletion of germ cells. Mean serum antisperm antibody levels were greater for animals with altered testes than for rats with normal testicular histology. In addition, the proportion of rats that showed a positive antisperm antibody response was greater among animals with testicular changes than among those with unaltered testes. When the present results on Sprague-Dawley rats were compared with previous findings on the highly responsive Lewis strain, it was evident that the incidence of testicular changes and the proportion of positive antibody responders were greater in the Lewis strain. However, elevated antisperm antibodies and testicular alterations appeared to be more tightly linked in the less responsive Sprague-Dawley rats. (J. Urol., 140:627–631, 1988)

Spermatic granulomas forming after vasectomy reversal have been thought to mechanically compromise the anastomosis. We have studied the physiologic effects of vasectomy and vasovasostomy in rats. Following delayed microsurgical vasovasostomy, fluid flow through the anastomosis and cauda epididymidal hydrostatic pressure are not significantly different in tracts that form, or do not form, sperm granulomas at the anastomosis. Given a properly performed microsurgical vasectomy reversal, a sperm granuloma arising from a small leak does not appear to mechanically compromise the anastomosis in the rat. Fertility after vasovasostomy is not significantly reduced in rats with granulomas.

An indirect enzyme-linked immunosorbent assay (ELISA) was employed to monitor antisperm autoantibodies in 16 Lewis rats for up to 36 weeks following vasectomy. This assay was capable of discriminating all prevasectomy from postvasectomy sera at a 1:16 dilution. Weekly serum samples were obtained for the first 13 weeks and bimonthly samples thereafter. Half of the animals developed a positive antisperm autoantibody response by the end of the first postoperative week. By the end of the second week, 81% of the animals had positive responses. The greatest proportion (88%) of animals having a positive response over the course of the study was found at the end of the seventh postoperative week and the highest mean absorbance value for all 16 animals was observed at this time. Only 25% of the animals had positive responses for antisperm autoantibody at the end of the 35th week of the study. These findings indicate that circulating antisperm autoantibodies arise in the Lewis rat earlier than has been generally appreciated. The time course is similar to that of antibody titers to infectious agents or arising from inoculation of rats with spermatozoa. These findings on autoantibody levels in the Lewis rat are compared with the dynamics of antisperm autoantibody formation in man.

The relationship between antisperm antibodies as determined by enzyme-linked immunosorbent assay (ELISA) and the occurrence of alterations in testicular weight and histology was studied following vasectomy in Lewis rats. The effects of vasovasostomy on antisperm antibody levels were also examined. At 1, 3, and 4 months after vasectomy, the mean absorbance values in an ELISA for sera from animals with altered testes was significantly greater than that from animals lacking testicular alterations. However, animals showing positive antisperm antibody responses were represented both in the group with testicular alterations and among those that lacked testicular damage. Levels of antisperm antibody in both vasectomy and vasovasostomy groups significantly exceeded that for sham-operated animals, but the level of antisperm antibodies in vasovasostomized animals with positive responses was similar to vasectomized animals one and four months after reanastomosis. It is suggested that persistence of antisperm antibodies or testicular alterations, or both, may play roles in limiting the restoration of fertility after vasovasostomy.

The occurrence of alterations in testicular weight and morphology after vasectomy and vasectomy reversal by vasovasostomy was studied in Lewis rats. Animals were studied 3, 4, and 7 months after bilateral vasectomy or a vasectomy followed 3 months later by vasovasostomy. Other rats served as shamoperated controls. The weights of the testes in vasectomy and vasovasostomy animals fell into two groups—small testes weighing less than 0.88 g and normal‐sized testes of 1.2 g or more. When the extent of testicular alterations was estimated in sections for light microscopy by use of a semiquantitative testicular biopsy score count (TBSC), the morphology of the testes corresponded closely to the testis weight (r = .94), small testes having correspondingly low TBSC scores. In severely altered small testes, the seminiferous tubules were narrower than in sham‐operated rats, and numbers of germ cells were greatly depleted. Many tubules contained only Sertoli cells and spermatogonia, although spermatocytes were present in a minority of tubules. A few seminiferous tubules contained multinucleate spermatids. Electron microscopy of severely altered tubules revealed closely apposed processes of Sertoli cells, which contained filaments, microtubules, and endoplasmic reticulum. In contrast, testes with normal weight in vasectomy and vasovasostomy groups resembled those of the sham‐operated animals. Comparison of distributions of testicular biopsy score counts demonstrated differences between vasectomy and vasovasostomy groups as time after operation increased. At the 3–4‐month intervals, approximately one‐third of the testes were severely altered in both vasectomy and vasovasostomy groups. However, by 7 months the proportion of altered testes progressed to 60% in animals with a vasectomy, while it remained similar to the earlier intervals in rats that had received a vasovasostomy. These results suggest that vasovasostomy may prevent the progression of testicular alterations that occur after vasectomy, but vasovasostomy does not appear effective in reversing testicular changes.

The occurrence of spermatic granulomas of the vas deferens was studied in Lewis rats at intervals up to 7 months after vasectomy or vasectomy followed 3 months later by vasovasostomy. The incidence of granuloma progressed with time to involve one or both tracts in 100% of vasectomized rats. In addition, the majority of animals developed new granulomas after vasovasostomy, even though fluid flow through the reconnected vas deferens was demonstrated in vitro. When individual tracts were analyzed, the weight of the testis was related to ipsilateral spermatic granuloma formation in both vasectomy and vasovasostomy groups at 3 and 4 months after initial operation. Testes were small in the absence of a granuloma but similar to those of sham‐operated rats if a granuloma was present. The possible protective effect of spermatic granuloma formation on the testis is discussed.

An indirect enzyme-linked immunosorbent assay (ELISA) was devised to measure antisperm auto-antibodies in the Lewis rat following vasectomy. The assay system was validated by employing prevasectomy sera and postvasectomy antisera, previously demonstrated to contain antisperm antibodies by indirect immunofluorescence. A standardized ELISA protocol was developed employing 10(5) sperm per microtiter plate well and sucrose-polyvinylpyrrolidone as a postcoat stabilizer solution. The ELISA was shown to yield significant detectable antibody at dilutions of 1/512 or greater in the most reactive sera. A standard for scoring positive titers was adopted: 1.96 standard deviations above the mean of the preimmune value. Using the criterion, 88% of 7-week postvasectomy samples could be discriminated from preimmune samples at a 1:16 dilution, which was adopted for subsequent assays. The ELISA demonstrated 73% and 91% reproducibility for an intraassay analysis of single prevasectomy and postvasectomy serum samples (7 weeks postvasectomy) tested in 160 determinations on a standard sperm pool. When this single antigen pool was employed in 35 determinations at 0, 1, and 4 weeks in an interassay study, 56% and 70% reproducibility was found for pre- and postvasectomy sera respectively. A correlation (r = 0.75) was made between a single absorbance value and the endpoint titer of the same sera, which indicated that single absorbance values could be used to predict serum titer and single dilutions could be used for general screening of a large number of samples. The ELISA described provides a rapid, sensitive, and reliable method that discriminated between samples taken before and after vasectomy.