Expression of Androgen related Fibroblast Growth Factor 8 pathway in Genital Tubercle of Hypospadiac Male Rats Following in Utero Exposure to Di-n-butyl phthalate

Abstract

Objective To evaluate the expression of Testosterone、Androgen Receptor and FGF8 in genital tubercle (GT) of hypospadiac male rats following in utero exposure to DBP,to investigate molecular mechanism of DBP on androgen related FGF8 pathway.Methods Twenty pregnant rats were randomly divided into 2 groups and given DBP by gastric intubation at a dose of 0,750 mg/kg from gestation day(GD) 14 to GD18.On postnatal day (PND) 1,male pups were examined for hypospadias.On PND7,the body weight of male pups were measured and the gross image of hypospadiac genitalia were checked.Real-time quantitative PCR and WesternBlot were used to evaluate expression of AR and FGF8 in the GT.Radio-immunoassay was used to evaluate testosterone concentration in the serum of hypopadiac rats.Results The number and body weight of live pups in the DBP group (9.10 ± 0.99;9.53 ± 0.12 g) was significantly lower when compared with the control group(12.60 ±1.26; 11.93 ± 0.15 g) ( P ＜ 0.05 ),and the incidence of hypospadias was 37.2 ％.Significantly decreased expression of AR and FGF8 were also found in both mRNA and protein levels in the DBP group(AR:0.404 ± 0.040; FGF8:0.036 ± 0.004),when compared with the control group(AR:1.669± 0.124; FGF8:0.168 ± 0.004) ( P ＜ 0.005 ).The testosterone concentration of DBP treating group (41.85 ± 8.38 ng/L) was also lower than control group( 107.40 ± 24.28 ng/L)(P＜0.05).Conclusions Toxic effects of DBP to pregnant rats were seen.The occurrence of hypospadias may be related to the interference on androgen related FGF8 pathway by DBP. Key words: Di-n-butyl phthalate; Hypospadias; Testosterone; Androgen receptors; Fibroblast