肉鸡肠道紧密连接蛋白基因表达的发育性变化

Developmental Changes of Expression of Tight Junction Protein Genes in Broiler Intestine

本试验旨在研究肉鸡不同肠段中紧密连接蛋白基因表达的发育性变化。选取60只1日龄的罗斯308肉鸡进行饲养,分别于1、3、7、14和28日龄采集6只肉鸡的十二指肠、空肠、回肠、盲肠和结肠组织并用玻片刮取肠道黏膜,采用实时荧光定量PCR(RT-qPCR)技术测定各个肠段中闭合蛋白(Claudin)-1和Claudin-2、闭锁蛋白(Occludin)、闭合小环蛋白(ZO)-1和ZO-2等紧密连接蛋白基因的相对表达量。结果显示:1)1日龄时,Claudin-1基因在十二指肠、空肠、回肠和盲肠中的相对表达量均显著高于其他日龄(P<0.05),而Claudin-2基因在各肠段中的相对表达量与其他日龄相比均为最低;盲肠和结肠中Claudin-2基因相对表达量均随日龄的增长先升高后降低,7日龄时最高。Claudin-2基因的相对表达量从十二指肠至结肠表现为逐渐降低。2)1日龄时Occludin基因在十二指肠、空肠、回肠和结肠中的相对表达量均显著低于其他日龄(P<0.05),十二指肠、空肠和回肠中Occludin基因的相对表达量随日龄的增长先升高后降低,以14日龄时最高。3)1日龄时ZO-1基因在各个肠段中的相对表达量均显著低于其他日龄(P<0.05);而ZO-2基因在十二指肠和空肠中的相对表达量随日龄的增长无显著变化(P>0.05),在回肠中的相对表达量则随日龄的增长逐渐升高,14日龄到达顶峰后下降。4)日龄、肠段均对各紧密连接蛋白基因的相对表达量有极显著影响(P<0.01),且日龄和肠段对各紧密连接蛋白基因相对表达量的影响具有极显著的交互作用(P<0.01)。结果表明,Claudin-1基因在各肠段中的相对表达量在1日龄时最高,Claudin-2、Occludin和ZO-1基因则相反,肉鸡肠道通透性在1日龄时最低,随后升高。Claudin-2基因的相对表达量从十二指肠至结肠表现为逐渐降低,肉鸡各日龄肠道前段(十二指肠、空肠和回肠)通透性高于肠道后段(盲肠和结肠)。不同紧密连接蛋白的发育性变化模式存在一定差异,且日龄和肠段对各紧密连接蛋白基因相对表达量的影响具有极显著的交互作用。

This experiment was conducted to investigate the developmental changes of expression of tight junction protein genes in different intestinal segments of broilers.The duodenal,jejunal,ileal,cecal and colonic tissue segments and mucous membrane were collected from 6 out of 60 fresh-hatched Ross 308 broilers at 1,3,7,14 and 28 days of age,respectively.The relative expression levels of tight junction protein genes including Claudin-1,Claudin-2,Occludin,zonula occluden(ZO)-1 and ZO-2 genes in each intestinal segment were detected by real-time fluorescent quantitative(RT-qPCR)technique.The results were as follows:1)at 1 day of age,the relative expression levels of Claudin-1 gene in the duodenum,jejunum,ileum and cecum were significantly higher than that at other days of age(P<0.05)whereas the relative expression level of Claudin-2 gene in all intestinal segment was the lowest(P<0.05).The relative expression level of Claudin-2 in the cecum and colon was increased with age increasing and reached the highest level at 7 days of age.The relative expression level of Claudin-2 gene decreased from duodenum to colon.2)The relative expression level of Occludin gene in the duodenum,jejunum,ileum and colon at 1 day of age was significantly lower than that at other days of age(P<0.05),while it in the duodenum,jejunum and ileum was increased with age increasing,and reached a peak at 14 days of age.3)The relative expression level of ZO-1 gene in all intestinal segments at 1 day of age was significantly lower than that at other days of age(P<0.05).The relative expression level of ZO-2 gene in the duodenum and jejunum was not significantly different with age increasing(P>0.05),while it in the ileum was increased with age increasing,reached a peak at 14 days of age and then decreased.4)Both age and intestinal segment had significant effects on the relative expression levels of tight junction protein genes(P<0.05),and the interaction effects of age and intestinal segment on the relative expression levels of tight junction protein genes were also significant(P<0.01).In conclusion,the relative expression level of Claudin-1 gene is the highest at 1 day of age,whereas Claudin-2,Occludin and ZO-1 genes are the opposite.The intestinal permeability of broilers is the lowest at 1 day of age and then increase.The relative expression level of Claudin-2 gene decreases gradually from duodenum to colon,and the permeability of anterior intestine(duodenum,jejunum and ileum)is higher than that of posterior intestine(cecum and colon).The developmental patterns of different tight junction proteins are different from each other,the interaction effects of age and intestinal segment on the relative expression levels of tight junction protein genes are significant.