益生菌对炎症性肠病幼鼠Th17细胞的调节作用

目的 观察鼠李糖乳杆菌（LGG）对炎症性肠病（IBD）幼鼠结肠白细胞介素-17A（IL-17A）水平的影响，探讨益生菌对Th17细胞的调节作用。方法 36只健康雄性SD幼鼠随机分4组：空白对照组、LGG对照组各8只，IBD组、IBD-LGG组各10只。利用2,4,6-三硝基苯磺酸（TNBS）诱导幼鼠IBD模型，观察一般状况、IBD疾病活动指数评分。第8天处死所有幼鼠，留取结肠标本，观察病理改变并采用免疫组织化学法测定结肠组织IL-17A的表达。结果 相比两对照组，IBD组、IBD-LGG组幼鼠一般状态差，IBD-LGG组便性状及隐血较IBD组缓解；IBD组、IBD-LGG组幼鼠结肠组织均见炎症改变，但IBD-LGG组较轻。IBD-LGG组DAI评分、IL-17A水平均低于IBD组，差异有统计学意义（P＜0.05）。结论 益生菌可减轻IBD幼鼠肠道炎症，其机制可能与益生菌调节Th17细胞进而调控IL-17A表达有关。

Regulatory effect of probiotics on Th17 cells in young rats with inflammatory bowel disease

Abstract: Objective To observe the influence of Lactobacillus rhamnosus GG on the level of IL-17A in the intestinal tissue of IBD (inflammatory bowel diseases) young rats, and discuss the regulatory effect of probiotics on Th17 cells. Methods Thirty-six four-week healthy male Sprague-Dswley rats were divided into the blank control group (n=8), LGG control group (n=8), IBD group (n=10) and IBD-LGG group (n=10) respectively. The IBD models were induces by using TNBS. The weights, fecal characters and occult blood and disease activity index (DAI) scores of all rats were observed every day until the eighth day when they were sacrificed. Then the pathological changes of lesions and the expression of IL-17 in the intestinal mucosa were determined with microscope and immunohistochemical staining method respectively. Results Compared with the control group, the rats in IBD group and IBD-LGG group appeared abnormal symptoms including poor appetite, loose fur, and being dull and apathetic, etc. After 3 to 4 days of treatment, the fecal property and occult blood in IBD-LGG group were significantly relieved compared with the IBD group. The two groups of IBD rats appeared significant intestinal inflammation changes, which was more serious in IBD group. The DAI score and the level of IL-17A in IBD-LGG group were lower than those in IBD group respectively with significant differences (Ps<0.05). Conclusion Probiotics can reduce intestinal inflammation in juvenile IBD rats; the mechanism may be related to the inhibition of cytokine IL-17A and the regulation of expression of Th17 cells by probiotics.