Early orchiopexy improves subsequent testicular development and spermatogenesis in the experimental cryptorchid rat model

Abstract

Purpose: The most appropriate period for orchiopexy is controversial. We performed histological analyses of undescended testes to evaluate the influence of orchiopexy timing in an experimental cryptorchid rat model. Furthermore, we extrapolated the timing of orchiopexy in humans from our results.

Materials and methods: Experimental cryptorchid rats were induced with androgen blocker by injecting flutamide into the abdomen of pregnant Sprague-Dawley rats (Chubu Kagaku Shizai, Nagoya, Japan) for 7 days from days 14 to 20 of gestation. Approximately 90% of male newborns had undescended testes and we performed orchiopexy on them 4, 5 and 7 weeks after birth. The testes were removed 10 weeks after birth in all groups, and weight and histological findings were assessed. A modified Johnsen score was used to determine spermatogenesis maturity and germ cell apoptosis was also evaluated.

Results: Nonoperated undescended testes showed atrophic and hypospermatogenesis with germ cell apoptosis, whereas treated undescended testes showed the development of early elongated spermatids. In addition, performing orchiopexy 4 weeks after birth decreased the degeneration of undescended testes compared with that in other groups.

Conclusions: From the point of view of only testicular development 4-week-old rats reportedly correspond to 1-year-old humans. While we should be cautious when extrapolating our findings to the clinical setting, our current study provides evidence in support of early orchiopexy during the first year of life.