全肠内营养对炎症性肠病幼鼠Th17细胞的调节作用研究

Exclusive enteral nutrition's moderating effect on Th17 cell of juvenile rat with inflammatory bowel disease

目的 利用TNBS诱导的炎症性肠病(inflammatory bowel disease,IBD)幼年大鼠模型,观察肠内营养制剂百普素喂养后,IBD幼鼠肠组织Th17细胞相关细胞因子IL-17A的水平变化,探讨肠内营养对Thl7细胞的调节作用.方法 选择健康的4周龄雄性SD幼年大鼠共计36只,随机分为空白对照组、全肠内营养(exclusive enteral nutrition,EEN)对照组每组各8只,IBD组、IBD-EEN组每组各10只:空白对照组及EEN对照组予生理盐水灌肠,后分别予普通饲料及肠内营养制剂百普素经口喂养;IBD组及IBD-EEN组予5%TNBS乙醇溶液灌肠,建造IBD模型,后分别予普通饲料及肠内营养制剂喂养.记录体重情况、便性状及隐血,依据Cooper评分进行IBD疾病活动指数评分(disease activity index,DAI).于实验第7天处死四组幼鼠,留取结肠组织标本,HE染色观察黏膜损伤情况,采用免疫组化法检测Th17细胞相关细胞因子IL-17A的表达水平.结果 与IBD组相比,IBD-EEN组在便性状及便血方面明显缓解.IBD组和IBD-EEN组体重均较前增长,7d后体重分别增长(39.95±2.929)g和(38.40±4.545) g(P >0.05).IBD组大体组织及病理切片显示肠道炎症改变明显,可见典型炎症性肠病改变,镜下可见肠黏膜大量炎症细胞浸润,部分可见炎性肉芽肿形成,腺体正常结构遭到破坏.给予EEN喂养后,DAI评分明显下降,肉眼可见肠道炎症减轻,镜下炎症细胞浸润减少.免疫组化法对黏膜组织的染色研究显示,IL-17A细胞因子的表达水平在IBD-EEN组肠黏膜中较IBD组明显减低,差异有统计学意义(P<0.05).结论 全肠内营养治疗可减轻IBD幼年大鼠肠道炎症,其机制可能与抑制Th17细胞的细胞因子IL-17A的表达有关.

Objective Through the TNBS-induced inflammatory bowel disease model in young rats,to observe the level of Th17 cell related cytokine IL-17A on the intestinal tissue of IBD young rats model after feeding EEN,Peptisorb,and investigate the enteral nutrition's regulative effects on Thl7 cells.Methods Thirty six four-week healthy male Sprague-Dswley rats were selected and divided into 4 groups,blank control group and EEN control group with 8 rats in each group,IBD group and IBD-EEN group with 10 rats in each group:blank control group and EEN control group were given normal saline enema,then fed with normal diet and enteral nutrition separately;IBD group and IBD-EEN group were given 5% TNBS enema,establish the IBD model,then fed with normal diet and enteral nutrition separately.The weights,defecate characters and occult blood situations of all rats were determined.Also,we carried out the activity index score of disease according to the Cooper score method.On the seventh day,all rats were sacrificed and the colon specimens were collected.We observed mucosal injury by HE staining and expression level of Thl7 cell related cytokine IL-17A that were detected by immunohistochemical staining.Results Compared with IBD group,IBD-EEN group was improved significantly in terms of defecate character and occult blood situation.Both IBD group and IBD-EEN group gained their body weights than before,(39.95 ± 2.929) g and (38.40 ± 4.545) g respectively after 7 days (P≥0.05).In IBD group,gross tissue and pathological section displayed significant intestinal inflammation change,showing typical inflammatory bowel disease change;under the microscope,intestinal mucosa showed a large amount of inflammatory cell infiltration,a part of section displayed inflammatory granuloma formation,normal glandular structure was damaged.After EEN treatment,DAI scores werr decreased significantly;intestinal inflammation changes were relieved;intestinal mucosa inflammatory cell infiltration were reduced.Immunohistochemical study showed that the expression of IL-17A cytokine in the intestinal mucosa of IBD group was higher than that of IBD-EEN group (P < 0.05).Conclusion The exclusive enteral nutrition treatment possessed the effect of reducing IBD young rat's intestinal mucosal inflammation,the inner mechanism may be related with the changing expression of Th17-cell cytokines,IL-17A.