ABSTRACT
<p><b>OBJECTIVE</b>To establish a mouse model of hypospadias induced by benzoate estradiol to further the studies on the molecular mechanisms of hypospadias.</p><p><b>METHODS</b>A total of pregnant mice were randomly divided into 5 groups, Group A, B, C, D and E, and injected subcutaneously (sc) with estradiol benzoate at the dose of 0, 0.2, 1, 5 and 25 mg x kg(-1) d(-1) respectively from the 12th to the 16th gestational day. The mortality of the newborn mice was recorded and the male neonates of 2 pregnant mice from each group were anatomized to observe the testis position and prostate agenesis on the delivery day. Examinations were made for urethra and cryptorchidism on the 28th postnatal day.</p><p><b>RESULTS</b>The death rates of the neonates in Group A, B, C, D and E were 21.6%, 21.5%, 41.4%, 56. 6% and 75.0%, respectively. Hypospadias was detected in Group C (3.3%, 1/30), D (20.0%, 4/20) and E (23.0%, 3/13), with significant difference between Group D and A (P < 0.05) and E and A (P < 0.05), but not between Group D and E (P > 0.05). Cryptorchidism was found in Group C (6.6%, 2/30) , D (30.0%, 6/20) and E (61.6%, 8/13), with significant difference between Group D and A (P < 0.05) and E and A (P < 0.05) , but not between Group D and E (P >0.05).</p><p><b>CONCLUSION</b>Exposure of pregnant mice to large dose of estradiol benzoate can induce hypospadias and cryptorchidism in their neonates. And the right dose of estradiol benzoate for the establishment of the mouse model of hypospadias should be 5 mg x kg(-1) x d(-1).</p>