[Expression of insulin-like factor 3 in the testis of flutamide-induced cryptorchidism mice and its significance].

OBJECTIVE: To study the changes in the mRNA expression of insulin-like factor 3 (INSL-3) in the testis of mouse models of flutamide-induced cryptorchidism. METHODS: We randomized pregnant BALB/c mice to groups A (control) , B, C, D and E to receive continuous gavage of flutamide at 0, 150, 300, 500 and 700 mg/kg body weight, respectively, from gestation day 12 to 21. We detected the expression of INSL-3 mRNA in the testis of the neonates by real-time PCR at 4 and 8 postnatal weeks. RESULTS: No cryptorchidism was found in group A; unilateral cryptorchidism was seen in groups B (10.0%) and C (25.0%); and bilateral cryptorchidism was observed in groups D (21.1%) and E (40.0%). The expression of INSL-3 mRNA was reduced with the increased dose of flutamide, not significantly changed in groups B and C (P > 0.05) but remarkably decreased in D and E as compared with A (P < 0.05). CONCLUSION: Administration of flutamide to pregnant mice can induce unilateral cryptorchidism at 150 and 300 mg/kg and bilateral cryptorchidism at 500 and 700 mg/kg in their male offspring, which may be related with its reducing effect on the expression of INSL-3 in the testis of the mice.

[Establishment of cryptorchid infertile models by postnatal injection of estradiol in mice].

OBJECTIVE: To investigate the incidence and spermatogenesis of cryptorchid testes induced by postnatal injection of estradiol. METHODS: Ninety male newborn Balb/C mice were randomly divided into an experimental (n = 60), a solvent control (n = 20) and a normal control group (n = 10). The experimental mice were again assigned to a 4-week, a 6-week, an 8-week, and a 10-week subgroup, and injected subcutaneously with 17-beta estradiol (5 microg/d) from 3 to 28, 3 to 42, 3 to 56 and 3 to 70 days after birth, respectively. The incidence of cryptorchidism and morphological changes of the testes were observed at 2 weeks after drug withdrawal. RESULTS: The incidence rates of cryptorchidism in the 4-, 6-, 8- and 10-week groups were 0%, 26.7%, 60% and 60%, respectively, but no cryptorchidism occurred in the solvent and normal control groups. The 4- and 6-week groups showed autonomous descent of the cryptorchid testes and recovery of spermatogenesis after drug withdrawal. The models became stable and no spermatogenesis recovery was observed after 8 weeks of continuous medication. CONCLUSION: Stable cryptorchid infertile models can be established in mice by postnatally continuous injection of estradiol for over 8 weeks.