Different Expression Of ATF3 In The Hypospadiac Male Rats Induced By Combination Of Di-n-butyl Phthalate (DBP) And Glucocorticoids

Objective To verify the differential expression of ATF3 in the genital tubercle(GT) of hypospadiac rats induced by maternal exposure to DBP or DBP+DXMamethasone (DXM) in order to stress the importance of combination of factors rather than single angents and to further explore the mechanism of hypospadias.Methods Eighty pregnant SD rats were randomly divided into four groups which were given: Group A: soybean oil oral gavage 2ml/d; Group B: DXM sc-injection 0.1mg/(kg·d); Group C: DBP oral gavage 700 mg/(kg·d); Group D: DBP(700mg/kg gavage)+DXM(0.1mg/kg sc-injection) during GD14-18. Half of the pregnant rats were killed at GD19, we recorded fetal rats'number, birth weight (BW), anogenital distance (AGD) and harvested GT to verify the expression of ATF3 by Western blotting and immunohistochemistry. The rest spontaneous labor rats were used to record the incidence of hypospadias and cryptorchidism at PND70.Results DXM alone had no effect except to reduce BW but can increase the teratogenic effect of DBP when combined with it. The BW and AGD/BW of group D was significantly lower than group C, and the incidence of hypospadias and cryptor- chidism vice versa. The incidence of cryptorchidism in group C was 58%,in group D was 88%. The incidence of hypospadias in group C was 37%,in group D was 60%. And the severity of hypospadias is according to PND70 rats genitals observation statistics. The expression of ATF3 in group A was:0.351±0.012(n=10), in group B was: 0.336±0.015(n=10), in group C was: 0.603±0.014(n=10), in group D was: 0.851±0.016(n=10), it had statistical difference between group C or D with A, as well as C with D (P<0.05). ATF3 was mainly located in the urethral epithelium and mesenchy- me, the result of staining intensity was in common with western blotting.Conclusion These results suggests that exposure to common environmental chemicals in combination with environmental endocrine disruptors, may increase the risk of male reproductive abnormalities, such as hypospadias. Up-regulation of ATF3 may affect urethral fold fusion, then lead to the occurrence of hypospadias.