Spermatic cord torsion. Contralateral testicular degeneration at various ages in the rat.

Unilateral spermatic cord torsion causes damage to the contralateral testis in humans and animals models. It is now known, however, at what age an animal's reproductive capacity is most susceptible to this type of trauma. To determine if the animal's age is a factor in its susceptibility to reproductive damage, rats at 30 to 70 days of age were subjected to unilateral spermatic cord torsion. Rats of the same ages underwent sham surgery and served as controls. The animals were allowed to recover from the surgery and to attain puberty before a period of fertility testing. Fertility, serum testosterone, organ weight, and testicular histologic data were obtained after the breeding period. Our data indicate that animals undergoing torsion at the youngest (30 days) and oldest (70 days) ages exhibited no change in the parameters studied. Animals between the ages of 35 and 50 days are highly susceptible to reproductive damage due to unilateral spermatic cord torsion, and the 35-day-old animals exhibit the most susceptibility. The stages of testicular development occurring during this period are such that damage to one testicle will result in degeneration of both organs. However, once the animal is older than 50 days, its reproductive capacity is not affected by spermatic cord torsion. The specific period of susceptibility in the development of human testes is yet to be defined.