Sperm antibodies in rat models of male hormonal contraception and vasectomy

The presence of sperm antibodies correlates with nearly every pathological condition of the male reproductive tract. In the seasonal breeder, mink, a decrease in gonadotrophin secretion and testicular regression also induces sperm antibodies. Because the Sertoli cells and the principal cells of the epididymis (i.e. the cells mainly responsible for protection of germ cells from autoimmune destruction) are dependent on androgens, and because the an drogen concentration decreases in both the testis and epididymis during mal e hormonal contraception, the presence of IgG class sperm antibodies in ser um was studied in rats during the suppression and recovery phases of testos terone contraception and after vasectomy. Five-centimetre long testosterone implants were placed under the dorsal skin of rats under pentobarbitone an aesthesia. The control rats received empty implants. All implants were left in the rats for 27 or 53 days. The total number of testicular antigens det ected by sera from the vasectomized rats increased significantly until 66 d ays post-operation, and then decreased to the levels of intact rats. The nu mber of testicular antigens detected by sera from rats receiving contracept ive doses of testosterone did not increase before the testosterone capsules were removed, but at 40 days post removal of the silastic capsules, the nu mber of antigens detected by the sera was significantly higher than in inta ct rats and at 77 days post removal of the silastic capsules, the number of antigens detected by the sera was significantly higher than at 27 days aft er starting testosterone administration. No significant changes in the numb er of antigens detected by the sera could be observed after the implanting of empty capsules or after their removal. Vasectomy mostly induced antibodi es against testicular antigens in the molecular ratio ranges of 70-82, 25-3 3 and 21-24.5 kD. Antibodies against antigens in these molecular ratio rang es were not significantly induced during or after treatment with contracept ive doses of testosterone. Cell nuclei with apoptotic morphology could be o bserved in the seminiferous tubules of the vasectomized rats, but DNA in si tu 3'-end labelling of testes could not confirm any differences between the testes of vasectomized and sham-operated rats or between testosterone-trea ted and empty implant-treated rats. CD3(+) T cells could not be observed in the testes of any of the treatment groups. These results suggest that the immunological conditions remain stable in the testes after vasectomy and du ring testosterone treatment, but that the animals are more prone to develop autoantibodies after vasectomy and during recovery from treatment with exo genous testosterone.