Spermatic granuloma of vas deferens after vasectomy in rhesus monkeys and men: light and electron microscopic study

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Non-proliferative and Proliferative Lesions of the Non-human Primate (M. fascicularis)

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in most tissues and organs from the nonhuman primate used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.

The contraceptive efficacy of intravas injection of Vasalgel™ for adult male rhesus monkeys

Background

Options for male contraception are limited. The purpose of this study was to use a nonhuman primate model to evaluate Vasalgel™, a high molecular weight polymer being developed as a contraceptive device for men.

Methods

Sixteen adult male rhesus monkeys received intravas injections of Vasalgel, consisting of 25% styrene maleic acid in dimethyl sulfoxide. After a one-week recovery, males were returned to outdoor group housing, which included at least 3 and up to 9 intact, breeding females with a successful reproductive history.

Results

Treated males have had no conceptions since Vasalgel injections. All males were housed with intact females for at least one breeding season and seven have been almost continually housed with females for 2 years. Complications were minor and included one incident of incorrect placement of Vasalgel into the vas deferens and the development of a sperm granuloma in one animal. Three unilateral vasectomies were performed, one was necessary for incorrect placement of Vasalgel, the other two were elective.

Conclusions

Intravas injection of Vasalgel in sexually mature adult male rhesus monkeys was effective in preventing conception in a free-living, group environment. Complications were few and similar to those associated with traditional vasectomy.

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.

Macrophages of the sperm granuloma 3 months after vasectomy in the Albino Swiss rat

This study documents the appearance and arrangement of the macrophages of the sperm granuloma 3 months after vasectomy in the Albino Swiss rat. We found, as have others, that the macrophages form a distinct layer in the granuloma wall, external to the central mass of extravasated spermatozoa. Those closest to the spermatozoa showed much phagocytosis. Many had two, three, or more nuclei. The largest macrophages, giant cells of the foreign body and Langhans types, were generally farther from the sperm mass, but retained evidence of phagocytic activity in the form of sperm fragments. Macrophages, either mono- or multinucleate, frequently showed numerous surface microridges that interdigitated with those of neighboring cells. The microridges varied in length, but were of uniform thickness and cytoplasmic content and were rarely branched. Monocytes were frequently observed, indicating continuing significant recruitment of cells of the macrophage series to the granuloma. We also noted mononucleate cells in the connective tissue external to the macrophage layer. Their cytology suggested they were macrophages, but they showed much less phagocytic activity than those of the main macrophage layer and had distinctive aggregations of moderately electron-dense droplets.

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.

Microrecanalization after vasectomy in man

Previously spermatozoa in the semen of vasectomized men were reported in 62 of 63 specimens from 24 men 2 to 31 years postvasectomy (Freund and Couture, 1982). A morphologic basis and term, "microrecanalization," was proposed for this observation. Serial sections (5 mu at 200-mu intervals) of 40 specimens removed at vasovasostomy from 20 men (2 to 14 years postvasectomy) were examined and microcanals (small epithelial-lined channels) were demonstrated in 27 specimens from 18 men. In nine of the 27 specimens, spermatozoa or sperm heads were found within the microcanals. Microcanals occurred in smooth muscle, connective tissue and scar tissue, in each segment, testicular, central and abdominal, in the presence or absence of the vas deferens. Microcanal continuity was traced for 200 to 1140 microns by computerized image analysis. Microrecanalization is characterized by the absence of inflammation or sperm extravasation and is histologically distinct from vasitis nodes or sperm granuloma. Microrecanalization provides morphologic and physiologic bases for the protection of the testis and maintenance of spermatogenesis in man after vasectomy.

Vasitis nodosa and associated clinical findings

To establish the prevalence of vasitis nodosa in patients who had undergone vasectomy segments of vas deferens resected from 40 patients at the time of vasectomy reversal were examined histologically and immunohistochemically. The findings were correlated with clinical history and postoperative outcome. Controls comprised segments of normal vas deferens excised at vasectomy. Twenty of the 40 vasovasostomy specimens showed vasitis nodosa; in 13 this was associated with sperm granulomas and in two with spermatocoeles. The vasitis nodosa was characterised by multiple small ductules extending from the central lumen of the vas into the muscle layers and adventitia. In 14 cases there was mucinous metaplasia of the epithelium lining the ductules. The number of nerve fibres in the submucosa and muscle layers was reduced after vasectomy. In patients with vasitis, however, hyperplasia of nerve fibres in the adventitia (16 of 20 cases) and formation of neuromas were seen. Nerve fibre hyperplasia was seen in only one, and sperm granulomas and spermatocoeles in none of the 20 specimens without vasitis nodosa. The development of vasitis nodosa was independent of the patients' age or the interval between vasectomy and reversal. The restoration of fertility did not seem to be affected by previous vasitis nodosa.

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.

Vasitis nodosa and spermatic granuloma of the skin: an histologic study of a rare complication of vasectomy

A 29-year-old man noticed localized painful swelling of the scrotal skin after elective vasectomy. The lesion was excised and its histologic examination revealed a diffuse inflammatory, partly granulomatous infiltrate with numerous tubular structures in the dermis and subcutaneous tissues. These ductules were lined by cuboidal epithelial cells and contained spermatozoa. The inflammatory infiltrate consisted of lymphocytes, plasma cells and histiocytes, but also contained spermatozoa and a few spermatic granulomas. These changes were the sequelae of a vasocutaneous adhesion and fistula; the ductules were the result of epithelial regeneration from the vas deferens and the inflammation with spermatic granulomas was due to extravasated spermatozoa.

Delayed spontaneous recanalization of the vas deferens

Eight patients were identified who had undergone successful vasectomy a mean of 4.6 years previously and in whom all were microscopically shown to have recurrent motile spermatozoa in their ejaculate. All had been referred following a pregnancy in their wives, and all agreed to undergo repeat vasectomy. Histological examination of the excised portions revealed the presence of spermatozoa in the distal end of one side; but also the presence of a well formed sperm granuloma in continuity with both divided ends of the vas. There does not appear to be any correlation with the suture previously used, nor incidence of infections or injury. Although recanalization is a recognized complication of vasectomy, the majority have occurred within months of the operation. The association of the delayed recanalization with sperm granuloma formation in these cases suggests an aetiological link, it being previously reported that such granuloma can develop up to six years postoperatively.

Experimental production of spermatic granuloma in Balb/c mice

The inflammatory reaction to extravasated spermatozoa was studied in mice by subcutaneous injection of small numbers of such cells. Spermatic granulomata developed several days later, probably as a result of the rather indigestible nature of many spermatozoal components. The granulomata persisted for several days before healing started.