The effects of immunosuppression on sperm granulomas in vasectomized rats

The weights and histologic appearances of sperm granulomas were compared in immunosuppressed and non immunosuppressed vasectomized rats. Three methods of immunosuppression included the administration of antilymphocyte serum, neonatal thymectomy plus administration of antilymphocyte serum and treatment with cyclophosphamide. The observations indicate that the sperm granuloma is primarily composed of a central core of packed, unabsorbed spermatozoa and that the initial histologic appearance at the periphery of the granuloma is not sensitive to immunosuppression. The findings indicate that the histology of the early sperm granuloma is not the result of an inflammatory process brought about primarily by autoimmune phenomena. The possibility that the absorption of spermatozoa in the granuloma might initiate an immune response effecting the histologic changes seen in older sperm granulomas has not been eliminated.