目的 研究安石榴苷对细菌性肠炎的改善作用及对肠道菌群的影响。方法 45只BALB/c小鼠采用致病性大肠杆菌O₁₀₁建立细菌性肠炎模型,给予安石榴苷或头孢克肟干预7 d,给药过程中观察各组小鼠的体征并计算每天的疾病活动指数(disease activity index,DAI)与体质量变化率;给药结束后取肠组织及肠道内容物,苏木素-伊红(HE)染色法观察小鼠肠组织的病理改变;免疫组化法检测小鼠小肠组织黏膜中闭锁连接蛋白-1(zonula occludens-1,ZO-1)和紧密连接蛋白(Occludin)的表达;测定小鼠肠组织髓过氧化物酶(myeloperoxidase,MPO)活性;qRT-PCR法检测小鼠肠壁炎症相关因子核苷酸结合寡聚化结构域蛋白2(nucleotide binding oligomerization domain 2,NOD2)、核因子-κB p65(nuclear factor-κB p65,NF-κB p65)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白细胞介素-6(interleukin-6,IL-6)mRNA的表达;ELISA法检测小鼠血清中脂多糖(lipopolysaccharide,LPS)、TNF-α和IL-6水平;16S rDNA高通量测序法检测小鼠肠道菌群多样性和丰度。结果 与模型组比较,安石榴苷组小鼠DAI评分显著降低(P<0.01);小肠黏膜充血、水肿明显减轻;小肠上皮中ZO-1和Occludin蛋白表达显著增多(P<0.01);肠壁MPO活性显著降低(P<0.01);肠壁NOD2、NF-κB p65、TNF-α和IL-6 mRNA表达水平显著降低(P<0.01);血清LPS、TNF-α和IL-6水平显著减少(P<0.01);肠道厚壁菌门(Firmicutes)、毛螺菌科(Lachnospiraceae)和Clostridiales-unclassified相对丰度显著升高(P<0.01),变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、Muribaculaceae和脱硫弧菌科(Desulfovibrionaceae)菌群相对丰度显著降低(P<0.05、0.01)。结论 安石榴苷能够改善致病性大肠杆菌O₁₀₁诱导的肠炎,减轻小鼠肠壁的炎症反应,保护肠黏膜屏障,其机制可能与调节肠道菌群有关。

Objective To study the improvement effect of punicalagin on bacterial enteritis and its influence on intestinal flora. Methods Forty-five BALB/c mice were ig pathogenic Escherichia coli O₁₀₁ to establish a bacterial enteritis model, and were given punicalagin or cefixime for 7 d of intervention. During the administration, signs of mice in each group were observed, daily disease activity index (DAI) and body weight change rate were calculated; Intestinal tissue and intestinal contents were collected after administration, and hematoxylin-eosin (HE) staining was used to observe the pathological changes of intestinal tissue in mice; Expressions of tight junction protein zonula occludens-1 (ZO-1) and Occludin in small intestine were detected by immunohistochemistry; Activity of myeloperoxidase (MPO) in intestinal tissue of mice was measured; Inflammation related factors nucleotide binding oligomerization domain 2 (NOD2), nuclear factor-κB p65 (NF-κB p65), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA expressions in intestinal were detected by qRT-PCR; Lipopolysaccharide (LPS), TNF-α, IL-6 levels in serum were determined by ELISA; Diversity and abundance of intestinal flora in mice were detected by 16S rDNA high throughput sequencing. Results Compared with model group, DAI score of mice in punicalagin group was significantly decreased (P < 0.01); Congestion and edema of small intestinal mucosa were significantly alleviated; Expressions of small intestinal epithelial tight junction associated proteins ZO-1 and Occludin were significantly increased (P < 0.01); MPO activity in intestinal wall was significantly reduced (P < 0.01); NOD2, NF-κB p65, TNF-α and IL-6 mRNA expressions in intestinal wall were decreased significantly (P < 0.01); LPS, TNF-α and IL-6 levels in serum were significantly decreased (P < 0.01); Relative abundances of Firmicutes, Lachnospiraceae and Clostridiales-unclassified were significantly increased (P < 0.01), relative abundances of Proteobacteria, Bacteroidetes, Muribaculaceae and Desulfovibrionaceae were significantly decreased (P < 0.05, 0.01). Conclusion Punicalagin can improve enteritis induced by pathogenic E. coli O₁₀₁, reduce the inflammatory response of mouse intestinal wall, and protect the intestinal mucosal barrier, and its mechanism may be related to the regulation of intestinal flora.

R285.5

安徽省高校自然科学重大项目（KJ2020ZD56）；大学生科研资助金项目（WK2020S59，WK2021XS61）