摘要目的 了解大鼠肠道上皮屏障功能随增龄所发生的变化. 方法 选用3月龄组、12月龄组、24月龄衰老模型鼠组,每组各10只.取大鼠末端回肠制作切片观察小肠黏膜形态学变化及绒毛高度、厚度等.采用免疫组化Envision两步法、反转录-聚合酶链反应(RT-PCR)方法检测大鼠末端回肠黏膜的紧密连接蛋白闭锁蛋白(Occludin)、闭锁小带蛋白(ZO-1)的分布和表达. 结果 24月龄衰老模型鼠、12月龄大鼠小肠黏膜厚度及绒毛高度均较3月龄降低[小肠黏膜厚度:24月龄(87.6±6.32)μm,12月龄(131.8±5.22) μm,3月龄(162.9±7.28)μm,P＜0.05;绒毛高度:24月龄(56.4±5.38)μm,12月龄(76.7±5.40)μm,3月龄(108.1±6.42)μm,P＜0.05],且24月龄衰老模型鼠小肠黏膜厚度及绒毛高度较12月龄亦降低(P＜0.05).24月龄衰老模型鼠、12月龄大鼠小肠黏膜组织中紧密连接蛋白(Occludin、ZO-1)表达均较3月龄减少[Occludin蛋白:24月龄(2.23±0.60)％,12月龄(4.21±0.61)％,3月龄(12.31±0.94)％,P＜0.05; ZO-1蛋白:24月龄(2.03±0.54)％,12月龄(4.02±0.65)％,3月龄(12.21±0.81)％,P＜0.05],24月龄衰老模型鼠小肠黏膜组织中紧密连接蛋白(Occludin、ZO-1)表达较12月龄亦降低(P＜0.05).24月龄衰老模型鼠和12月龄大鼠小肠黏膜组织中Occludin mRNA和ZO-1mRNA相对表达量较3月龄减少(OccludinmRNA:24月龄0.20±0.03,12月龄0.38±0.02,3月龄0.66±0.03,P＜0.05；ZO-1mRNA:24月龄0.18±0.03,12月龄0.37±0.02,3月龄0.63±0.03,P＜0.05),24月龄衰老模型组与12月龄组比较差异有统计学意义(P＜0.05). 结论 随着年龄的增长大鼠小肠黏膜厚度及绒毛高度逐渐降低,小肠黏膜的紧密连接蛋白逐渐减少,小肠黏膜屏障功能受损.

abstractsObjective To study the changes of intestinal epithelial barrier function in rats with aging.Methods SD rats were divided into 3 groups:3-month-old group (group A),12-month-old group (group B) and 24-month-old group (group C,established by D-galactose injection with the dose of 0.125 g· kg-1 · d-1subcultaneously for 6 weeks) (n=10,each).The terminal ileum was obtained to make microtome section,and the morphology of small intestine mucous membrane,trophonema altitude and thickness were observed under light microscope.Occludin and ZO-1 protein expressions in terminal ileum mucous membrane were detected by immunohistochemistry.The expressions of Occludin and ZO 1 mRNA were determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR).Results The small intestinal mucosa thickness and villus height were lower in group C and B than in group A [thickness:(87.6± 6.32) μm,(131.8± 5.22) μm vs.(162.9±7.28) μm; villus height:(56.4±5.38) μm,(76.7±5.40) μm vs.(108.1±6.42) μm;both P＜0.05].The small intestinal mucosa thickness and villus height was lower in group C than in group B (both P＜0.05).Occludin and ZO-1 protein expressions in small intestine tissue were reduced in group C and B as compared with group A [Occludin protein:(2.23±0.60)％,(4.21±0.61)％ vs.(12.31±0.94)％; ZO-1 protein:(2.03±0.54)％,(4.02±0.65) ％ vs.(12.21±0.81)％ ; both P＜0.05],and Occludin and ZO-1 protein expressions were less in group C than in group B (both P＜0.05).The levels of Occludin and ZO-1 mRNA in small intestine tissue were reduced in group C and B as compared with group A [Occludin:(0.20±0.03),(0.38±0.02) vs.(0.66±0.03) ; ZO-1:(0.18±0.03),(0.37±0.02) vs.(0.63±0.03); both P＜0.05],and Occludin and ZO-1 mRNA expressions were less in group C than in group B (both P ＜ 0.05).Conclusions The small intestinal mucosa thickness and villus height are reduced,the levels of Occludin and ZO-1 expressions are significantly decreased in small intestinal mucosa,and the intestinal barrier function is impaired with rat aging.