邻苯二甲酸二丁酯干预雄激素依赖性FGF8信号通路致尿道下裂发生的实验研究

目的 通过检测邻苯二甲酸二丁酯(DBP)孕期染毒所致尿道下裂雄性大鼠仔鼠睾酮(T)、雄激素受体(AR)及成纤维细胞生长因子8(FGF8)的表达,研究DBP干预雄激素依赖性FGF8通路致尿道下裂发生的相关机制.方法 20只孕鼠随机分为两组,孕14～18 d,分别予大豆油及DBP 750 mg·kg-1 ·d-1灌胃.仔鼠出生第一天,统计仔鼠出生数、尿道下裂发生率.第七天时,称量雄性仔鼠体重,拍摄尿道下裂图片,分别取两组中尿道下裂仔鼠及正常仔鼠血清和生殖结节(GT),用放射免疫法检测仔鼠血清睾酮含量；用定量逆转录聚合酶链式反应(Real-time quantitative PCR)及WesternBlot检测AR与FGF8表达水平.结果 染毒组及对照组产仔数分别为9.10±0.99和12.60±1.26,仔鼠体重(g)分别为9.53±0.12和11.93±0.15,DBP的生殖毒性作用导致染毒组孕鼠产仔数及仔鼠体重明显减少(P＜0.05),雄性仔鼠尿道下裂发生率为37.2％.染毒组仔鼠血清睾酮浓度(41.85±8.38) ng/L、生殖结节中AR0.404±0.040及FGF 80.036±0.004的表达均明显低于对照组睾酮浓度( 107.40±24.28) ng/L、AR表达1.669±0.124及FGF8表达0.168±0.004(P＜0.05).结论 DBP对孕鼠有明显的生殖毒性,DBP通过干预雄激素依赖性FGF8信号通路,导致尿道下裂的发生.

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

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.