复合益生元制剂对右旋葡聚糖硫酸钠诱导溃疡性结肠炎小鼠肠道菌群的影响

Effects of compound prebiotic preparation on intestinal flora in mice with ulcerative colitis induced by dextran sodium sulfate

目的研究复合益生元制剂对右旋葡聚糖硫酸钠(DSS)诱导的溃疡性结肠炎(UC)小鼠的治疗效果及其作用机制。方法将40只雄性C57BL/6小鼠按照随机数字表法分为对照组、模型组、美沙拉嗪组和益生元组,每组10只。对照组连续7 d给予饮用水,其余3组连续7 d自由饮用3%DSS水溶液建立UC小鼠模型。造模成功后第1天起美沙拉嗪组和益生元组同步灌胃给药(10 ml/kg),对照组和模型组给予等体积生理盐水,连续9 d,每天记录小鼠体重、粪便性状及便血情况;9 d后处死小鼠,测量结肠长度,HE染色评估小鼠结肠组织病理学变化,ELISA法检测结肠组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)和白细胞介素-6(IL-6)水平,并通过16S rRNA测序法检测小鼠肠道菌群的变化。结果与模型组相比,益生元组制剂给药治疗后小鼠体重降低减缓,腹泻和便血症状显著改善,差异有统计学意义(P<0.05),结肠黏膜病理损伤显著减轻(P<0.05),结肠组织TNF-α、IL-6水平均显著降低[(945.3±7.23)ng/ml vs.(1069.0±12.07)ng/ml,(178.0±1.24)ng/ml vs.(182.7±1.16)ng/ml],差异有统计学意义(P<0.05)。UC小鼠肠道菌群多样性降低,经复合益生元制剂治疗后,菌群多样性有一定的提高,在门水平上主要表现为厚壁菌门和变形菌门显著降低,拟杆菌门丰度增高,属水平上主要为Muribaculaceae_unclassified和拟杆菌属丰度增高,螺杆菌属丰度降低。结论复合益生元制剂可有效治疗UC小鼠,其通过恢复和改善肠道菌群多样性调节UC小鼠的肠道菌群组成,从而发挥治疗作用。

Objective To study the therapeutic effect and action mechanism of compound prebiotic preparation on ulcerative colitis(UC)induced by dextran sulfate sodium(DSS)in mice.Methods Forty male C57BL/6 mice were randomly and equally divided into control group,model group,mesalazine group,and prebiotic group.The control group was given drinking water for seven consecutive days,and the remaining threeg roups were given free access to 3%DSS aqueous solution for seven consecutive days to establish UC mouse models.After successful modeling,the mice were administered by gavage(10 ml/kg)in the mesalazine and probiotic groups on the first day,and the control and model groups were given equal volume of saline for nine consecutive days.The body weight,fecal traits,and hematochezia of the mice were recorded daily.The mice were sacrificed after nine days,the length of the colon was measured,the histopathological changes of colon were evaluated by HE staining,and the levels of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),and interleukin-6(IL-6)in colon tissues were detected by ELISA,and the changes of intestinal flora in the mice were detected by 16S rRNA sequencing method.Results Compared with the model group,the colitis symptoms,including weight loss,diarrhea,and hematochezia,of mice in the prebiotic group were significantly alleviated(P<0.05).Colonic mucosal pathologic injuries and the levels of TNF-αand IL-6[(945.3±7.23)ng/ml vs.(1069.0±12.07)ng/ml,(178.0±1.24)ng/ml vs.(182.7±1.16)ng/ml]were all significantly reduced(P<0.05).The UC mice had a decreased gut microbiota diversity,and that diversity was increased to some extent after the treatment of compound prebiotics.The phyla Firmicutes and Proteobacteria were significantly decreased,while the abundance of Bacteroidetes was increased.The genera Muribaculaceae unclassified and Bacteroides were significantly increased,while the abundance of Helicobacter was decreased.Conclusion Compound prebiotic preparation is effective in treating UC mice,which is achieved by regulating the composition of intestinal microflora in UC mice by restoring and ameliorating the microflora diversity,and its curative effect is better than the positive drug mesalazine.