Effect of Preoperative Human Chorionic Gonadotropin on Intra-Abdominal Rat Testes Undergoing Standard and Fowler-Stephens Orchiopexy

Abstract

Purpose We attempted to determine whether preoperative human chorionic gonadotropin (HCG) improves fertility in intra-abdominal rat testes subjected to orchiopexy. Materials and Methods Newborn male Sprague-Dawley rats were made cryptorchid by bilateral gubernaculum excision at age 14 days. Select rats served as controls and underwent sham operations. Half of the animals were injected with 10 international units HCG daily from days 14 to 28. On day 28 the animals were divided into group 1-6 that underwent sham operation with or without HCG, group 2-6 with cryptorchidism with or without HCG, group 3-22 that underwent standard orchiopexy with or without HCG and group 4-22 that underwent Fowler-Stephens orchiopexy with or without HCG. Contralateral orchiectomy was performed simultaneously. On day 65 each male rat was mated with 2 female rats for 3 ovulatory cycles. Results Mean testicular weight was markedly decreased in cryptorchid compared to sham operated testes (87.2 versus 344 mg./100 gm. body weight). Mean testicular weight was similar after standard and Fowler-Stephens orchiopexy. HCG enhanced mean testicular weight after sham operation, standard orchiopexy and Fowler-Stephens orchiopexy (403 versus 344, 193 versus 176 and 194 versus 175 mg./100 gm. body weight, respectively) but these differences were not statistically significant. Fertility was present in all 6 sham operated, 0 of the 6 cryptorchid, 1 of the 11 standard orchiopexy and 1 of the 8 Fowler-Stephens orchiopexy rats. Of the HCG treated animals 2 of the 8 that underwent Fowler-Stephens orchiopexy and 1 of the 8 that underwent standard orchiopexy were fertile. Mean weight of the testes associated with pregnancy was significantly greater than those not associated with pregnancy (p <0.001). Conclusions The intra-abdominal rat testis has limited fertility potential after orchiopexy that is not improved with preoperative HCG. After orchiopexy fertility correlates closely with testicular weight.