HoxA13基因在尿道下裂胎鼠阴茎中的表达及意义

HoxA13 mRNA and protein expression and its etiology value in mice genitalia of hypospadias induced by exposing to Di（2-ethylhexyl） phthalate

目的研究尿道下裂胎鼠阴茎中HoxA13核酸及其蛋白的表达，探讨其与尿道下裂发生的相关性。方法选用清洁级C57BL／6小鼠，用邻苯二甲酸二（2-乙基）己脂（DEHP）诱导并建立先天性尿道下裂模型；交配怀孕后，孕鼠随机分为玉米油对照组、实验组（DEHP500mg·kg^-1·d^-1）；各组持续灌胃；于怀孕第19天取出仔鼠，测量各组雄鼠体重、AGD；统计各组胎鼠尿道下裂的发生率，并观测阴茎的组织病理学变化；应用常规RT-PCR及免疫组织化学方法检测诱导出的尿道下裂胎鼠及正常对照胎鼠阴茎组织中HoxA13的mRNA及蛋白表达水平。结果对照组、实验组的AGD值分别为（0．208±0．01）cm、（0．181±0．12）cm，P〈0．01；尿道下裂发生率分别为0％、75．7％，P〈0．01。实验组胎鼠尿道板及包皮于阴茎腹侧隆起融合落后，该组尿道与腹侧皮肤间的皮下组织明显减少。DEHP500mg·kg^-1·d^-1诱导的尿道下裂胎鼠阴茎组织中HoxA13mRNA及蛋白表达较对照组明显降低。结论DEHP能影响胎鼠的生长发育及体重，并导致雄鼠外生殖器发育异常；HoxA13mRNA及蛋白的表达在DEHP诱导的尿道下裂胎鼠阴茎中均较正常对照组降低，提示HoxAl3基因异常表达可能是尿道下裂的发生机制之一。

Objective To investigate the role of HoxA13 in mice genitalia of hypospadias, we compared the gene＇ s mRNA/protein expression in normal versus hypospadic mice penil using molecular localization techniques. Methods Pregnant C57BL/6 mice were selected and randomly divided into two groups：one treated with Di（2-ethylhexyl）phthalate 500 mg. kg-1 . d-1 and the mice in control group were receiced same volume of corn oil. Fetal mice were harvested at GD19. The body weight and anogenital distance of male fetal mice were measured. And the incidences of hypospadic genitalia as well as the changes of the histopathology in each group were examined. Subsequently, the mRNA and protein levels of HoxA13 in genitalia were determined using RT-PCR and immunohistochemistry. Results The incidence of hypospadie genitalia were higher obviously than those in control group（ incidence of hypospadic genitalia 75.5% , 0% , P 〈 0.01 ; AGD：0. 208 ± 0. 01, 0. 181 ±0.12, P 〈 0.01 ） ; The result of histopathology in genitalia ： the procedure of development of the penile urethra involves the movement or growth of the urethral folds toward the midline fell behind. HoxA13 mRNA expressions in fetal mice genitalia of hypospadias were reduced obviously than those in control. HoxA13 protein also expressed in epidermis. In tissue of hypospadias, the protein showed weakly positive, but manifes- ted strongly positive in the controls. Conclusion DEHP is very toxic to the fetal mice including urogenital development and body weight, and can induce hypospadias in fetal male mice. HoxA13 mRNA/protein expres- sions in fetal mice genitalia of hypospadias were reduced obviously than those in control. It cued that the relationship of HoxA13 and hypospadias was closely.