Bcl-2和Bax基因在肛门直肠畸形胎鼠泄殖腔胚胎发育中的表达

摘要

Objective To determine Bcl-2 and Bax gene expression patterns in normal and anorectal malformation (ARM) fetal rats,and to investigate their roles in the cloacal embryonic development.Methods Pregnant rats on embryonic day 10 (E10) were intragastric administrated with ethylenethiourea (125 mg/kg) to generate ARM fetal rats.The expression of apoptotic genes Bcl-2 and Bax in the cloaca were detected by SABC immunohistochemical staining in the fetal rats from both control group and ARM group on E13,E13.5,E14,E15 and E16.Results Bcl-2 and Bax expression was observed in the epithelial layer and mesenchyme of urorectal septum during the cloacal embryonic development in the control group.Among which,Bax expression was higher than Bcl-2.A large number of Bax positive cells were found in the epithelial layer on E13 and the positive cells gradually decreased with the development of normal embryos.The Bax positive cells in the mesenchyme peaked on E13.5 and E14.Compared with the control group,the Bax positive cells in the epithelial layer and mesenchyme of ARM fetal rats were significantly less on E13.5 and E14.Similarly,many Bcl-2 positive cells were seen in the epithelial layer on E13 and gradually decreased after that.There were few Bcl-2 positive cells in the mesenchyme of urorectal septum.On E13.5,the Bcl-2 positive cells were obviously increased in the epithelial layer and mesenchyme of ARM fetal rats compared with the control group.Conclusion In ARM fetal rats,the abnormal expression of Bcl-2 and Bax genes on E13.5 and E14 might be related to the development of ARM.%目的 检测Bcl-2和Bax基因在正常胎鼠和肛门直肠畸形(ARM)胎鼠泄殖腔胚胎发育过程中的表达.方法 在胚胎发育第10天(E10),乙烯硫脲致畸产生ARM胎鼠.在胚胎发育第13(E13)、13.5(E13.5)、14(E14)、15(E15)和16(E16)天时,应用免疫组织化学方法进行Bcl-2和Bax抗体的染色,检测Bcl-2和Bax基因在正常和ARM胎鼠泄殖腔的时空表达情况.结果 在泄殖腔胚胎发育过程中尿直肠隔上皮层和间质均表达Bcl-2和Bax基因,Bax的表达强于Bcl-2.上皮层E13时Bax阳性细胞比例高,随着发育成熟阳性细胞逐渐减少,间质在E13.5、E14时阳性细胞数达到高峰；而ARM胎鼠E13.5、E14时上皮和间质表达Bax明显减弱.Bcl-2阳性细胞在对照组上皮层E13时最明显,后逐渐减少,间质仅有少量染色阳性细胞,而ARM上皮和间质在E13.5时表达增强.结论 ARM胎鼠E13.5、E14时泄殖腔Bcl-2、Bax基因表达异常,影响泄殖腔细胞凋亡,可能与ARM的发生有关.