全反式维甲酸诱导大鼠肠神经系统发育异常的实验研究

目的利用全反式维甲酸(all-trans retinoic acid,ATRA)制作大鼠肠神经系统发育异常的动物模型,检测蛋白基因产物9.5(protein gene product 9.5,PGP9.5)及突触素(synaptophysin,SY)在胎鼠直肠肠壁胚胎发育过程中的分布,了解视黄酸(retinoie acid,RA)信号系统在鼠肠神经系统发育中的作用。方法妊娠SD母鼠共16只,随机分为两组,实验组在孕10d予ATRA一次性灌胃,对照组仅给等量橄榄油。孕20 d剖宫取出胎鼠,进行形态学观察和伴发畸形统计,HE染色和以PGP9.5、SY为肠神经系统(enteric nervous system,ENS)发育标志物的免疫组化SP法。结果对照组获胚胎70只,未见畸形,末端结肠及直肠壁内有神经节细胞,肠壁肌层及黏膜肌层PGP9.5及SY大量阳性表达,沿肠壁呈棕黄色颗粒分布;实验组获胚胎98只,可见先天性肛门直肠畸形及伴发畸形,直肠末端PGP9.5及SY阳性表达分布均比对照组减少。用QWIN3000生物图像分析软件测定随机选定切片视野内的平均阳性面积百分比,所有数据经秩和检验得出PGP 9.5及SY在对照组的表达高于实验组(PGP 9.5:W=1035.00,Z=-8.386,P=0.000<0.01;SY:W=820,Z=-8.121,P值=0.000<0.01),差异有统计学意义。结论 ATRA可成功诱导大鼠肠神经系统发育异常,提示视黄酸信号系统在消化道和神经嵴源性器官胚胎发育中起重要作用。

Experimental Study on the Developmental Abnormalities of Enteric Nervous System Induced by All-trans Retinoic Acid in Rats

Objective To detect distribution of PGP9.5 and SY in the fetus rectum wall during embryonic development and to investigate the effect of All-trans retinoic acid(ATRA) on the enteric nervous system(ENS) dysplasia.Methods 16 pregnant rats were divided into two groups.10 rats in experimental group were gavage-fed with ATRA(dissolved in mineral oil) at 100mg.kg-1 b.w.on E10(day 10 of gestation).The control group received the same volume of mineral oil on the same day.Fetuses were recovered by Caesarean section on E20 respectively and fetal rats were counted after an observation of malformation under stereomicroscope.Expression of PGP 9.5 and SY in above samples were analyzed by immunohistochemical SP method.Results In control group,70 fetal rats were found and no abnormality showed.In ATRA-induced teratogenicity group,98 fetal rats were found and showed ARMs.End of the colon and rectum had the ganglion cells in controls.PGP9.5 and SY were expressed in the myenteric plexuses and submucous plexusand brown particlesdistributed along the intestinal wall in control group.The average percentage of positive area in slice view measured with QWIN3000 biological image analysis software showed SY and PGP 9.5 in the control group was significantly higher than those in the experimental group(PGP 9.5: W = 1035.00,Z =-8.386,P value = 0.000;SY: W = 820,Z =-8.121,P value = 0.000).Conclusion ATRA can successfully induce ENS dysplasia and RA signaling system plays an important role in the embryonic development of digestive tract and neural crest source organ.