Reversibility of azoospermia induced by bacillus Calmette-Guerin.

A single intratesticular injection of bacillus Calmette-Guerin induces azoospermia within 3 to 6 weeks in a variety of animals without loss of androgens. After a period of azoospermia, the return of spermatogenesis was observed in dogs and monkeys. Seven dogs that showed aspermatogenesis after a local instillation of bacillus Calmette-Guerin (20-110 units per testis) again demonstrated spermatogenesis after a period of 153 to 325 days of azoospermia. Sperm counts and motility were restored to preimmunization levels within 6 weeks after initiation of spermatogenesis. In one dog, systemic treatment with antimycobacterial drugs helped to clear the bacillus Calmette-Guerin from the testis, thus hastening the reinitiation of spermatogenesis. In two monkeys injected with 110 and 160 units of bacillus Calmette-Guerin, azoospermia lasted up to 150 days. Subsequently, fertility was restored and the treated animals sired healthy offspring. A second injection of bacillus Calmette-Guerin of a lesser dose (5-20 units per testis) in these fertile dogs and monkeys again produced azoospermia. Histologically, the monkeys having a second period of azoospermia demonstrated aspermatogenic orchitis in the testis and leukocyte infiltration in the interstitium. A majority of the tubules had intact basement membranes, with a block of spermatogenesis at the spermatocyte stage. In dogs, the second azoospermia lasted for 113 to 277 days with a subsequent restoration of sperm counts and sperm motility to preimmunization levels. There were no circulating antisperm antibodies detected in sera of these animals during the azoospermic period or during its reversal. These observations suggest that the bacillus Calmette-Guerin-induced azoospermia is reversible, both in terms of sperm count and fertility.