The Effects of Immunosuppression on Sperm Granulomas in Vasectomized Rats

Abstract

The relationship between automimmunity and sperm granulomas was investigated by histological study of these lesions in immunosuppressed and nonimmunosuppressed rats. To produce immunosuppression the thymus-dependent lymphocyte component of cell-mediated immunity was reduced by the administration of antilymphocytic serum. In others further suppression of thymus-dependent lymphocyte response was sought by neonatal thymectomy plus the serum. In another group the alkylating agent cyclophosphamide (cytoxan) was used 40 mg/kg (lethal dose 80) to block dexocyribonucleic acid synthesis in rapidly dividing precursors of immunocompenten cells. Proof of immunosuppression was shown by the ability of the treated animals to accept allogeneic skin grafts for 21 days. Vasectomies were done leaving the ends of the severed vas deferens unligated. All rats were sacrificed 21 days after vasectomy. Average weights of sperm granuloma were increased in the immunosuppressed animals. Sections of testicular tissue and of granulomas were examined histologically. Spermatogenesis had continued. Testicular and epididymal histology remained normal. The granulomas were composed of a central core of packed unabsorbed spermatozoa surrounded by a paracentral core of histiocytic cells and a peripheral fibrous zone. Polymorphonuclear leukocytes were present in the paracentral zone. Lymphocytes and plasma cells predominated in the fibrous zone. The immunosuppression had no effect on the formation of sperm granulomas suggesting that sperm granuloms do not indicate autoimmunity. Nor are they the result of an inflammatory process brought about primarily by autoimmune phenomena.