Ultrastructure of epididymal interstitial reactions following vasectomy and vasovasostomy

Influence of reproductive tract obstruction on expression of epididymal proteins and their restoration after patency

Vasectomy is a simple and reliable method of male contraception. A growing number of men after vasectomy request vasectomy reversal due to various reasons. The pregnancy rate is lower than the patency rate after vasovasostomy and the pregnancy rate is time dependent. In this study, we evaluated the influence of reproductive tract obstruction on expression of epididymal proteins and their restoration after patency. Adult male Wistar rats were studied 30, 60 and 120 days after vasectomy, 30 days after vasovasostomy or after sham operations. Two-dimensional gel electrophoresis, mass-spectrometric technique, multidatabase search, Western blotting and real-time PCR were used to analyze the expression regulation of epididymal proteins. Total integrated intensity and total spot area of autoradiograms showed a consistent downward trend with time after obstruction, and this trend remained after patency. The intensity of the autoradiographic spots in three patency groups showed three trends: a downward trend, similar intensity and an upward trend compared with the correspondent obstruction group, respectively. Further verified experiments on human epididymis 2 (HE2), fertilization antigen-1 (FA-1), clusterin and PH20 demonstrated that compared with the correspondent obstruction group, the translation levels of HE2 and the mRNA transcription levels of HE2 showed an upward trend in patency groups, especially in the groups of obstruction for 60 days where the expression levels of HE2 were significantly upregulated after patency (P<0.05). Reproductive tract obstruction provokes a disregulation of gene expression in the epididymis and this disregulation remained after patency. Successful reversal may recover some proteins and the recovery is time dependent. Obstruction differentially alters mRNA transcription of different proteins and the content of proteins seemed to be easier to be influenced than the gene transcription.

Cellular responses to vasectomy

A number of cell populations in the reproductive tract show a response to vasectomy. Some cell types show similar responses in man and all laboratory species, whereas others show marked species variations. This chapter describes these effects in a broadly chronological order and, in a general way, considers changes close to the site of vasectomy first and the longer term effects on the testis itself later. Following vasectomy, epididymal distension and sperm granuloma formation result from raised intraluminal pressure. The sperm granuloma is a dynamic structure and a site of much spermatozoal phagocytosis by its macrophage population. In many species, spermatozoa in the obstructed ducts are destroyed by intraluminal macrophages, and degradation products, rather than whole sperm, are absorbed by the epididymal epithelium. Humoral immunity against spermatozoal antigens following vasectomy is well established and there is evidence of modest T-lymphocyte activity. The role of lymphocytes in the reproductive tract epithelium and interstitium following vasectomy is poorly defined. In laboratory animals, there is evidence that pressure-mediated damage to the seminiferous epithelium can follow sperm granuloma formation and obstruction in the epididymal head. However, the contribution of lymphocytes and antisperm antibodies to testicular damage after vasectomy is far from clear. A number of studies have suggested that testicular changes may follow vasectomy in man but their validity and mechanism of occurrence require further study.

Intravasal azoospermia: a surgical dilemma

OBJECTIVES

To determine the incidence of intravasal azoospermia (IVA) and evaluate which factors before and during surgery influence outcome, by prospectively and intentionally performing bilateral vasovasostomies (VVs) only in men with intraoperative IVA.

PATIENTS AND METHODS

Using a multilayer technique, 472 men underwent microsurgical reconstructive procedures. Intravasal fluid was examined for sperm by the surgeon and a pathologist. Strict enrolment criteria included total absence of sperm or sperm parts and bilateral VV as a treatment procedure. Patients were followed up by semen analysis and paternity assessed only by naturally conceived pregnancies.

RESULTS

Of the 472 patients, 27 (5.7%) had bilateral IVA; 15 of these patients were available for a follow-up of 1-47 months. Eleven patients had identical gross appearance of intravasal fluid bilaterally. Of these patients, five had sperm in the ejaculate after surgery (three with clear intravasal fluid and two with no fluid). Bilaterally different vasal fluid was found in four men. Unilateral clear fluid was present in three patients, two of whom had sperm in semen analysed after VV. Overall, there was sperm in the ejaculate in seven of 15 patients with IVA; five of these seven had clear fluid in at least one vas deferens. One patient with unilaterally clear fluid achieved paternity by a naturally conceived pregnancy. The difference between the mean (SEM) obstruction interval in men who had sperm in a semen sample after VV, at 16.7 (3. 30) years, and in persistently azoospermic patients, at 15.5 (1.89) years, was not statistically significant (P = 0.741).

CONCLUSION

The results of VV in patients with IVA are unsatisfactory; the patency rate is higher in men with copious clear fluid in at least one vas. The obstructive interval in patients with IVA does not appear to influence the outcome of VV.

Morphological and histochemical changes in the epididymis of hamsters (Mesocricetus auratus) subjected to short photoperiod

The morphological involution and histochemical changes of the Syrian hamster (Mesocricetus auratus) epididymis induced by a short light period were investigated. Under short-day conditions, the epididymis showed marked morphological changes including a decrease in luminal diameter, disappearance of spermatozoa, increase of interductal tissue, increase of intraepithelial lipofuscin deposits, the presence of phagolysosomes in the principal cells and macrophage-like cells, and a considerable modification of most clear cells. With lectin histochemistry changes were found in the glycoconjugates of principal cells of the regressed epididymis, either a decrease (PNA, WGA, HPA and DBA) or an increase (MAA) in the affinity of lectins to the Golgi area, or a decrease (HPA) or an increase (PNA) in lectin binding to stereocilia. Both morphological and histochemical results showed that, under this light condition, the cauda epididymidis presented the most prominent alterations, and that the epididymis showed increased absorptive activity and a decreased synthesis of glycoproteins. All these changes are probably due to the decrease in testosterone levels.

A novel approach to the generation of antibodies against phylogenetically preserved sperm antigens

Conventional methods for immunization of laboratory animals against human spermatozoa proved not to be efficient enough to identify phylogenetically conserved sperm-specific antigens. A combination of vasectomy and subcutaneous administration of autologous testis homogenates was tested in 5 New-Zealand rabbits, and in 7 Long-Evans and 8 Spraque-Dawley rats in an attempt to induce an autoimmune response against such antigens. This experimental procedure resulted in a generation of sperm autoantibodies cross-reactive with human, rabbit and rat spermatozoa, as demonstrated by sperm-agglutination, ELISA and flow cytometry (FCM). No specific binding to human seminal plasma was detected by ELISA, indicating that intrinsic sperm membrane antigens rather than sperm-coating antigens were involved in establishing cross-reactivity with human spermatozoa. This suggestion was confirmed by the finding that rabbit autoantisera reacted more strongly against epididymal than against ejaculated human spermatozoa as shown by FCM. Humoral antispermatozoal response correlated well with impaired spermatogenesis in rabbits. The autoimmunized rats revealed severe alterations in reproductive tissues, including testicular and epididymal sperm granulomas; however, they showed a lower incidence of circulating antibodies. The results indicate that the established experimental model in rabbits can be further used to identify and characterize evolutionary preserved intrinsic sperm membrane autoantigens, which are desirable candidates for contraceptive vaccine development.

Initial phase of an inflammatory reaction in testis caused by experimental testicular autoimmunity in the Nile tilapia, Oreochromis niloticus

In order to study the pathogenesis of the testicular autoimmunity induced by the immunization with allogeneic testis homogenate (ATH) mixed with Freund's complete adjuvant (FCA) in the Nile tilapia Oreochromis niloticus, the initiation of inflammatory reactions in the testis was ultrastructurally investigated and seminal plasma was analyzed for presence of autoantigens. In the seminal plasma, mainly 120 kD and 80 kD autoantigens were identifiable by Western blotting with tilapia antisperm autoantibody. Eight weeks after injection with FCA, globate structures, possibly originating from FCA, were large and distended the interstitium where the inflammatory reactions were more frequently recognizable. The globate structures may be one of causes to break the blood-testis barrier, and the inflammatory reaction may be due to the leakage of soluble autoantigens from the lumen. In the interstitium, several kinds of immunocompetent cells formed masses which were mainly composed of lymphocytes, macrophages, eosinophils and plasma cells. We suggest that the inflammatory reactions in fish caused by the immunization with ATH+FCA are initiated by sensitization of the immunocompetent cells with testicular autoantigens, the 120 kD and 80 kD autoantigens in the seminal plasma are two of them, leaking from the lumen because of the provable effect of FCA. These initial reactions were then amplified by cellular and humoral immunity.

Antisperm autoantibody responses to vasectomy and vasovasostomy in Fischer and Lewis rats

Antisperm autoantibodies were studied in Fischer and Lewis strains of rats after either vasectomy, vasectomy followed one month later by vasovasostomy, or sham operations. The time course of antibody response to sperm protein autoantigens was assayed by Western blot analysis of sera obtained at intervals up to 3 months. Rats of both strains responded to immunization with isologous spermatozoa with production of high titer hyperimmune sera. Sera from vasectomized Fischer rats showed antisperm antibodies on Western blots, but bands were stained with less intensity and frequency than for Lewis rats. In both Fischer and Lewis strains, major protein autoantigens were observed at 75-83, 68-71, 63, 57, 51, 41, and 21-23 kDa, lending support to the hypothesis that there is a set of dominant sperm autoantigens recognized by a consensus of postvasectomy rat sera. The lesser response of Fischer rats to vasectomy was not due to absence of dominant postvasectomy sperm autoantigens in Fischer sperm extracts, nor was it attributable to inability of Fischer rats to mount an immune response to these antigens, since immunization with isologous sperm was successful in raising antibodies to the dominant autoantigens. Vasovasostomy did not result in a general decrease in antisperm antibodies, and reactions to some antigens actually increased.

Effects of vasectomy on the epididymis

Common principles can be discerned in the response of the epididymis to vasectomy, despite species differences. Increases in the size and number of lysosomes are the most frequent changes in the epididymal epithelium. The presence or absence of additional alterations such as changes in the height of the epithelium may be related to variations in distensibility of the vas deferens and epididymis. Direct measurements by micropuncture of epididymal and seminiferous tubule hydrostatic pressure indicate that, contrary to dogma, increased pressure in the distal epididymis after vasectomy is not generally transmitted to the seminiferous 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 higher antisperm antibody levels than animals lacking epididymal changes. Macrophages and neutrophils may enter the duct through the epididymal epithelium, at sites of rupture of the duct, and in the efferent ductules. Cyst-like spermatic granulomas occur in virtually all species where the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanical 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 that closely resembles the antigens bound by sera from rats immunized with isologous spermatozoa. There are multiple routes for disposal of the sperm that continue to be produced after vasectomy.

Immunology of the testicular excurrent ducts

The sperm autoantigen concentration in the epididymis equals or exceeds that in the testis. This makes the epididymis a probable site of initiation of an antisperm autoimmune response. The mechanisms regulating antisperm antibody formation in the testicular excurrent ducts and some related aspects with clinical interest are reviewed.