肠内生态营养对小肠损伤模型大鼠肠道免疫功能的影响

摘要

Objective To investigate the effects of enteral ecological nutrition on intestinal immune function and Hh protein expression in intestinal mucosa of rats with small intestinal injury and explore the mechanism. Methods Thirty male clean grade Wistar rats were selected as study subjects. The rats were randomly divided into a model group and an enteral ecotrophic group with 15 rats in each group. The small intestinal injury model was prepared by trauma method. After successful modeling, Six hours after successful establishment of the model, the rats in the two groups were fed with 753.12 kJ·kg-1·d-1 energy, 3 times a day. The rats in the model group were fed with conventional diet, while the rats in the enteral ecotrophic group were fed with enteral nutrition emulsion +Lactobacillus, bifidobacterium triple viable bacteria by intragastric administration of 1×107 cfu/d. After 10 days, the rats were killed, the small intestine of the two groups was dissected and stained with hematoxylin-eosin (HE) staining, and the morphological changes of small intestinal mucosa (villus height, glandular recess depth, mucosal thickness) were observed in the two groups; the expressions of CD3+, CD4+, CD8+ positive T cells in small intestinal mucosa were evaluated by immunohistochemistry; the expression of Hh protein in small intestinal mucosa was detected by Western Blot in the two groups. Results On the first day after the establishment of the model, the weight of rats in both groups was lower than that before the modeling [model group (g): 118.0±4.2 vs. 121.7±5.2, enteral ecotrophic group (g):117.5±4.7 vs. 120.8±5.0, P > 0.05], from the fifth day after the modeling, the weight of the rats in the enteral ecotrophic group was significantly higher than that of the model group (g: 127.1±5.0 vs. 123.2±4.2, P < 0.05), continued to 10 days (g: 142.5±6.6 vs. 135.3±6.2, P < 0.05). After the establishment of the model for 10 days, the small intestinal villus height, glandular recess depth, mucosal thickness and percentages of CD3+, CD4+ and CD8+ positive T cells in enteral ecotrophic group were significantly higher than those in model group [villus height (μm): 221.7±25.0 vs. 159.5±20.8, glandular recess depth (μm): 79.39±12.65 vs. 67.87±7.79, mucosal thickness (μm): 254.7±51.8 vs. 209.0±27.2, CD3+: 0.193±0.035 vs. 0.125±0.031, CD4+: 0.130±0.027 vs. 0.104±0.015, CD8+: 0.165±0.026 vs. 0.137±0.027, all P < 0.05]. The expression of Hh protein in the enteral ecotrophic group was obviously higher than that in model group (Hh/β-actin: 0.16±0.04 vs. 0.04±0.02, P <0.05). Conclusion Enteral ecological nutrition may promote the repair of intestinal mucosa and the improvement of immune function level by enhancing the expression of Hh protein in small intestinal mucosa of rats with small intestinal injury.%目的 观察肠内生态营养对小肠损伤模型大鼠肠道免疫功能、肠黏膜Hh蛋白表达的影响,并探讨其作用机制.方法 选择雄性清洁级Wistar大鼠30只,将大鼠按随机数字表法分为模型组和肠内生态营养组,每15只.采用创伤法复制小肠损伤模型.制模成功6 h后,两组大鼠开始以753.12 kJ·kg-1·d-1的能量进行饲喂,每日3次.模型组大鼠给予常规饲料饲养;肠内生态营养组同时给予肠内生态营养制剂(肠内营养制剂+双歧杆菌乳杆菌三联活菌)1×107 cfu/d灌胃.10 d后处死大鼠,取小肠组织进行苏木素-伊红(HE)染色,观察两组小肠黏膜形态学变化(绒毛高度、腺隐窝深度、黏膜厚度);采用免疫组化法检测两组小肠黏膜CD3+、CD4+、CD8+阳性细胞表达情况;采用蛋白质免疫印迹试验(Western Bolt)检测两组小肠黏膜Hh蛋白表达水平.结果 制模后1 d,两组大鼠体质量均较制模前降低〔模型组(g):118.0±4.2比121.7±5.2,肠内生态营养组(g):117.5±4.7比120.8±5.0〕,从制模后5 d开始,肠内生态营养组大鼠体质量明显高于模型组(g :127.1±5.0比123.2±4.2,P＜0.05),并持续到10 d(g :142.5±6.6比135.3±6.2,P＜0.05).制模后10 d,肠内生态营养组小肠绒毛高度、腺隐窝深度、黏膜厚度和CD3+、CD4+及CD8+阳性细胞比例均明显高于模型组〔绒毛高度(μm):221.7±25.0比159.5±20.8,腺隐窝深度(μm):79.39±12.65比67.87±7.79,黏膜厚度(μm):254.7±51.8比209.0±27.2,CD3+:0.193±0.035比0.125±0.031,CD4+:0.130±0.027比0.104±0.015,CD8+:0.165±0.026比0.137±0.027,均P＜0.05〕.肠内生态营养组大鼠小肠黏膜组织Hh蛋白表达水平明显高于模型组(Hh/β-actin:0.16±0.04比0.04±0.02,P＜0.05).结论 肠内生态营养可通过增加小肠损伤大鼠肠黏膜Hh的蛋白表达水平,促进肠黏膜的修复及免疫水平的提高.