| dc.description.abstract |
The presence of sperm antibodies correlates with nearly every pathologicalcondition of the male reproductive tract. In the seasonal breeder, mink, adecrease in gonadotrophin secretion and testicular regression also inducessperm antibodies. Because the Sertoli cells and the principal cells of theepididymis (i.e. the cells mainly responsible for protection of germ cellsfrom autoimmune destruction) are dependent on androgens, and because theandrogen concentration decreases in both the testis and epididymis during malehormonal contraception, the presence of IgG class sperm antibodies in serumwas studied in rats during the suppression and recovery phases of testosteronecontraception and after vasectomy. Five-centimetre long testosterone implantswere placed under the dorsal skin of rats under pentobarbitone anaesthesia.The control rats received empty implants. All implants were left in the ratsfor 27 or 53 days. The total number of testicular antigens detected by serafrom the vasectomized rats increased significantly until 66 dayspost-operation, and then decreased to the levels of intact rats. The number oftesticular antigens detected by sera from rats receiving contraceptive dosesof testosterone did not increase before the testosterone capsules wereremoved, but at 40 days post removal of the silastic capsules, the number ofantigens detected by the sera was significantly higher than in intact rats andat 77 days post removal of the silastic capsules, the number of antigensdetected by the sera was significantly higher than at 27 days after startingtestosterone administration. No significant changes in the number of antigensdetected by the sera could be observed after the implanting of empty capsulesor after their removal. Vasectomy mostly induced antibodies against testicularantigens in the molecular ratio ranges of 70-82, 25-33 and21-24.5 kD. Antibodies against antigens in these molecular ratio rangeswere not significantly induced during or after treatment with contraceptivedoses of testosterone. Cell nuclei with apoptotic morphology could be observedin the seminiferous tubules of the vasectomized rats, but DNAin situ 3′-end labelling of testes could notconfirm any differences between the testes of vasectomized and sham-operatedrats or between testosterone-treated and empty implant-treated rats. CD3<emph type="7">+ T cells could not be observed in the testes ofany of the treatment groups. These results suggest that the immunologicalconditions remain stable in the testes after vasectomy and during testosteronetreatment, but that the animals are more prone to develop autoantibodies aftervasectomy and during recovery from treatment with exogenous testosterone. |
|