Formation of antisperm autoantibodies in rats vasectomized at prefertile age

Sperm mitochondria-associated cysteine-rich protein (SMCP) is an autoantigen in Lewis rats

A common repertoire of rat sperm antigens have previously been identified by Western blotting of sperm proteins with sera obtained after vasectomy or isoimmunization with sperm. Aside from a determination of their apparent masses, however, the biochemical characteristics of these antigens have remained unknown. In this study, a rat testis cDNA expression library was screened with polyclonal antibodies obtained from rats immunized with isologous spermatozoa to identify and sequence a full-length clone encoding rat sperm mitochondria-associated cysteine-rich protein (SMCP). The open reading frame of SMCP was expressed in the pET22b vector, and recombinant SMCP (rec-SMCP) was purified. Sera from rats that had been vasectomized or hyperimmunized with isologous sperm specifically recognized rec-SMCP whereas preimmune sera from these experimental groups did not react. Rabbit antiserum produced to rec-SMCP recognized rec-SMCP on Western blots and precisely immunolocalized SMCP to the mid-piece of rat sperm. On Western blots against sperm extracts, the rabbit antibody recognized a major protein band of approximately 22-25 kDa that co-migrated with bands of identical mass that were recognized by sera from hyperimmune or vasectomized rats. These findings demonstrate that SMCP is a sperm autoantigen, recognized following vasectomy, and an isoantigen, recognized by antibodies generated through isologous immunization with sperm.

Appearance of 'natural' antisperm autoantibodies after sexual maturation of normal Lewis rats

Serum antisperm antibodies were assessed quantitatively with an ELISA in normal male Lewis rats at intervals between ages 10 and 128 days, spanning the onset of puberty. Antisperm antibodies rose between 56 and 91 days, and were significantly higher in 91- and 128-day old rats than at earlier intervals. The animals underwent normal pubertal development as indicated by increases in weights of the seminal vesicles and ventral prostate. The rise in antisperm antibodies correlated temporally with events in the postnatal development of the male reproductive system, with the increase in antisperm antibodies most closely following the time when spermatozoa reach the epididymis and proximal vas deferens at approximately 56 days. The observation that serum antisperm antibodies increased only after sexual maturation suggests that some differentiation antigens of sperm are processed and presented to the immune system under normal circumstances in this strain. Western blot analysis showed that the sera from normal postpubertal Lewis rats bound several proteins, including bands of > 100, 82-75, 78, 68, 65, 63, 54-55, 42, 37, 35, 26, and 20-22 kDa. The majority of these autoantibodies were sperm-specific as shown by the absence of comigrating bands in western blots of somatic tissue extracts, although antibodies in postpubertal sera recognized certain other proteins in somatic tissues. Several protein autoantigens, defined by sera from postpubertal animals, matched dominant autoantigens recognized by antibodies produced in response to vasectomy, prepubertal vas obstruction, or immunization with spermatozoa. This finding indicates that the antisperm antibody responses following sperm immunization, vasectomy or prepubertal vasal obstruction represent accentuation of an autoantibody response to sperm that develops normally following puberty.

Fertility after autotransposition of vas: a comparative study of absorbable and nonabsorbable suture material in rats

The anastomosis patency after autotransposition of vas (ATV) using an absorbable and a nonabsorbable suture material (10-0 Vicryl vs Ethilon) and the fertility have been investigated in a rat model. The patency rate and fertility in the absorbable group were 84% and 48%, respectively, compared with 93% and 59% in the nonabsorbable group. Sperm granulomas occurred in 60% and 48%, respectively. Sperm antibodies were present in 36% of the cases but did not have an impact on the fertility. The fertility after ATV seems to be comparable to the fertility in experimental and clinical vasovasostomy series. Further, the two suture materials appear equivalent with respect to patency and fertility in ATV.

Experimental vas replacement by either vas or a vascular graft

An experimental model for vas replacement by transplantation of either vas or a vascular graft in attempt to restore patency in cases of a substance loss of vas that cannot be overcome by vasovasostomy was developed. Three transplant lengths, representing 10, 20 and 30% of the entire vas length, were used. The results showed an overall patency of 43% but for the transplant length representing 10% of the vas patency was achieved in approximately 75% of the cases regardless of the type of transplant used. Unpatency was usually due to occlusion of the proximal anastomosis, which in turn was considered to be due to a combination of unfavourable nutritional, neural and surgical factors. It is concluded that vas replacement by transplantation using either vas or a vascular graft is possible to perform experimentally and gives acceptable patency rates up to a transplant length of 10% of the entire vas length.

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.

Autotransposition of vas in a 2-stage procedure. An experimental study in the rat

The patency rate of vasovasostomy in autotransposed vas has been studied using a technique set up in a rat model. In a two-stage procedure, 1 cm of the vas deferens was transposed to the opposite side. The anastomoses were performed with a simplified microsurgical suturing technique. On final examination, 9 of 15 rats operated upon showed good sperm passage over the transposed vas segment. Sperm granulomas were recorded in four of fifteen cases. Sperm antibodies were demonstrated in eight of fifteen cases.

Pathologic changes in the accessory sex glands of rats treated with a sympatholytic hypotensive agent (losulazine)

Groups of 25 male Sprague-Dawley rats were treated by gastric intubation with either vehicle control (modified methylcellulose) or a suspension of losulazine at 4, 8, 16, or 32 mg/kg/day for 1 yr. Ten rats/group were killed after 6 months of treatment. Reversibility of drug-induced changes was evaluated in 8 rats/group treated for 6 months and held without treatment for 5 months. Daily clinical signs and weekly body weight changes were monitored. Seminal vesicle/coagulating glands were weighed in rats treated for 6 months. Gross and microscopic evaluation of the accessory sex glands (ampullary glands, prostate, seminal vesicles and coagulating glands) was conducted in all rats killed at 6 months, after the recovery period, and in rats that survived through the one-yr treatment period. Ptosis, somnolence, and fecal softening were detected in all groups treated with losulazine. There was a nonreversible body weight gain retardation in groups treated with 8 to 32 mg/kg/day of losulazine for 6 months or 1 yr. Absolute and relative weights of the seminal vesicle/coagulating glands of treated rats were not significantly different from those of control rats. The ventral prostate in a few rats in all treated groups had yellow to tan granular foci. Treatment, but not dose-related sperm granulomas or glandular impaction with inspissated secretion (formation of corpora amylacia) in the ampullary glands, enhanced cellular exudation into the acini of the ventral prostate, and impaction of the seminal vesicles with altered granular to globular secretion were found in rats treated with losulazine.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal appearance of antisperm autoantibodies in Lewis rats following vasectomy

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.

Occurrence of sperm antibodies in adult rats after prefertile traumatic vas lesions

The occurrence of sperm antibodies has been studied in adult rats, which at prefertile age had been subjected to unilateral vasectomy, unilateral or bilateral crush injury of the vas or bilateral resection of the ductal artery. By means of indirect immunofluorescence technique, circulating sperm antibodies could be demonstrated in the blood in all groups 13 weeks postoperatively: unilateral vasectomy 15/17 (88%), unilateral crush injury 14/20 (70%), bilateral crush injury 13/20 (65%) and vascular injury 14/20 (70%). Sperm granulomas were observed in the unilateral vasectomy group (14/17) and in the bilateral crush injury group (4/20), whereas no sperm granulomas were seen in the unilateral crush injury or the vascular injury group.

The incidence of spermatic granulomas and their relation to testis weight after vasectomy and vasovasostomy in Lewis rats

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.