Akt信号通路在邻苯二甲酸二丁酯诱导雄性胎鼠发生尿道下裂中的表达研究

Differential expression of Akt signaling pathway in the hypospadiac male fetal rats induced by dibutyl phthalate

目的:邻苯二甲酸二丁酯(dibutyl phthalate,DBP)孕晚期暴露诱导子代Spraque-Dawley大鼠发生尿道下裂,探讨Akt信号通路及其下游关键蛋白核转录因子κB(nuclear factor-κ-gene binding,NF-κB)在胎鼠生殖结节中的差异表达,研究该通路在DBP致大鼠生殖系统发育异常过程中的作用机制。方法:孕SD大鼠20只,随机分为染毒组和对照组,在妊娠时间(gestation day,GD)14～18 d,每天通过灌胃分别给予DBP 800 mg/kg和大豆油,在GD19时提取染毒组发生尿道下裂胎鼠与对照组胎鼠的生殖结节组织,用Western blot检测磷酸化Akt(p-Akt)、Akt和NF-κB的表达情况,同时用免疫组化分析p-Akt的表达情况。结果:尿道下裂组与对照组中p-Akt、Akt和NF-κB相对表达量的比值分别为3.057±0.026、2.624±0.073和3.524±0.035(n=10,P<0.05),且尿道下裂组中p-Akt蛋白相对量在总蛋白中所占的比例较对照组高。p-Akt定位于生殖结节上皮细胞,尿道下裂组p-Akt染色明显强于对照组。结论:DBP干预大鼠生殖结节中Akt信号通路及其下游NF-κB的正常表达,进而影响了上皮细胞增殖、凋亡及尿生殖褶的融合,这可能是尿道下裂发生的机制之一。

Objective：To evaluate the differential expression of Akt signaling pathway in the genital tubercle （GT） of hypospadiac Spraque-Dawley rats induced by maternal exposure to dibutyl phthalate （DBP） and the control rats in order to further explore the mechanism of hypospadias. Methods： Twenty pregnant rats were randomly divided into two groups and administered with DBP at a dosage of 800 mg/kg or soybean oil intragastrically from gestation day （GD）14 to GD18. On GDl9,the expression of Akt signaling pathway was analyzed by Western blot and immunohistochemistry. Results：The expression of phosphorylated Akt （p-Akt）,Akt and NF-KB had statistical difference between hypospadiac fetal rats and control （P 〈 0.05）. The p-Akt was mainly located in the cytoplasm of epithelium; the staining intensity in the hypospadiac fetal rats was stronger than that in the control rats. Conclusion： Maternal exposure to DBP could increase the expression of Akt signaling pathway in GT epithelium,affect cellular proliferation, apoptosis and urethral fold fusion, and then result in the occurrence of hvpospadias.