The effect of graded unilateral testicular biopsy on the reproductive capacity of male rats.

Fifty adult rats were subjected to unilateral testicular biopsy removing either 0.01, 0.1, 0.2 or 0.3 cc of testicular parenchyma. In addition, 20 rats underwent either hemicastration or sham surgery. After a 30-day recovery period each male was housed with two cycling females for 20 days. At the end of this breeding trial the percentage of fertile males, percentage of pregnant females and resulting embryo scores (no. of embryos X size of embryos) were determined for each group of male rats. After an additional 30 days (60 days post-biopsy) a second breeding trial was performed so as to note any long-term changes in fertility. In addition to the fertility parameters, mean seminiferous tubule diameters and serum testosterone levels were noted. After the first breeding trial the percentage of fertile males and percentage of pregnant females were inversely proportional to the amount of biopsy material removed (p less than 0.05). However, the hemicastrate and sham-operated groups did not differ from the O cc control animals. The results of the second breeding trial showed a significant improvement in the percentage of females becoming pregnant (p less than 0.05) and a tendency for improvement in the percentage of fertile males when compared to data of the first breeding trial. In addition, we found the mean seminiferous tubular diameter of the biopsied testes to be inversely proportional to the size of the biopsy (p less than 0.01) with no apparent effect on the contralateral testes. We conclude that removing relatively large amounts of testicular parenchyma during unilateral testicular biopsy transiently affects male reproductive capacity, at least in the healthy animal model studied here.