A Mouse Model of Hypospadias Induced by Estradiol Benzoate

We wished to establish a mouse model of hypospadias using injections of estradiol benzoate for investigating the molecular mechanisms of hypospadias. Fifty timed pregnant mice were randomly divided into five study groups: A, B, C, D, and E. These groups were injected subcutaneously with estradiol benzoate mixed with sesame oil at, respectively, the doses of 0, 0.1, 0.5, 2.5, or 12.5 mg kg(-1) days(-1) from gestation day (GD) 12 to GD 16. The pups' mortality was recorded on the day of delivery. Urethras and positions of testes were examined on postnatal day 28. The numbers of live pups were significantly lower in the study groups D and E compared to study group A (p < 0.01). Hypospadias was seen in groups C (3.3 %; 1/30), D (18.2 %; 4/22), and E (21.4 %; 3/14), while cryptorchidism was observed in groups C (10 %; 3/30), D (31.8 %; 7/22), and E (57.1 %; 8/14) on postnatal day 28. The experimental model of hypospadias induced by estradiol benzoate in the group D (2.5 mg kg(-1) days(-1)) was more reliable considering high mortality of the study group E. The dose of estradiol benzoate used in the group D is suitable for establishing mouse model of hypospadias.