复合膳食纤维改善小鼠便秘及其作用机制研究

Study on the improvement of constipation and its mechanism of compound dietary fiber in mice

中文关键词:  便秘  复合膳食纤维  短链脂肪酸  肠道菌群

英文关键词:constipation  compound dietary fiber  short-chain fatty acids  intestinal microbiota

中文摘要:

      目的 研究复合膳食纤维对便秘小鼠的通便作用, 探讨其对小鼠肠道菌群及短链脂肪酸(short-chain fatty acids, SCFAs)的影响。方法 选取BALB/c小鼠, 除空白对照组外, 其余小鼠通过灌胃盐酸洛哌丁胺建立便秘小鼠模型。造模成功后的小鼠随机分为模型组、聚乙二醇4000散组、复合膳食纤维低、中、高剂量组, 分别给予维持饲料、聚乙二醇4000散加维持饲料、含2.5%、5.0%、7.5%复合膳食纤维的纯化饲料进行干预。干预14 d后, 通过排便实验、小肠推进实验, 验证复合膳食纤维的润肠通便效果, 并采集粪便检测短链脂肪酸的含量以及通过16s rDNA高通量测序分析肠道菌群组成。结果 复合膳食纤维能降低便秘小鼠的首粒排黑便时间, 增加5 h内排便数量及重量, 提高粪便含水量和小肠推进率, 可在一定程度上促进乙酸、丙酸、丁酸、戊酸、异丁酸、异戊酸的分泌; 在门水平上, 显著上调Verrucomicrobiota的相对丰度、下调Bacteroidota相对丰度, Firmicutes的相对丰度无明显变化; 在属水平上, 上调有益菌Akkermansia、Faecalibaculum和Bifidobaculum的相对丰度。结论 复合膳食纤维可以有效改善小鼠便秘, 其机制可能是通过调节肠道菌群组成以及促进SCFAs分泌实现的。

英文摘要:

      Objective To study the effects of compound dietary fiber on constipation in mice, and investigate the effects of dietary fiber on intestinal microbiota and short-chain fatty acids (SCFAs) in mice. Methods BALB/c mice were selected for the study. Except for the blank control group, all other mice were induced to establish a constipated mouse model by intragastric administration of loperamide hydrochloride. After successful modeling, the mice were randomly divided into the model group, polyethylene glycol 4000 group, and low, medium, and high dose groups of compound dietary fiber. They were respectively given maintenance feed, polyethylene glycol 4000 granules combined with maintenance feed, and purified feed containing 2.5%, 5.0%, and 7.5% compound dietary fiber for intervention. After 14 days of intervention, the laxative effect of compound dietary fiber was verified through defecation experiments and small intestine propulsion experiments. Fecal samples were collected to detect the content of short-chain fatty acids and analyze the composition of intestinal microbiota through 16S rDNA high-throughput sequencing. Results Compound dietary fiber reduced the first black stool expulsion time in constipated mice, increased the number and weight of stools within 5 hours, raised the fecal water content and small intestinal propulsion rate. It also promoted secretion of acetic acid, propionic acid, butyric acid, valeric acid, isobutyric acid, and isovaleric acid to some extent. At phylum level, it significantly increased the relative abundance of Verrucomicrobiota and decreased relative abundance of Bacteroidota, with no significant change in the relative abundance of Firmicutes. At genus level, it increased the relative abundance of beneficial bacteria Akkermansia, Faecalibaculum, and Bifidobaculum. Conclusion The compound dietary fiber can effectively improve constipation in mice. The mechanism may be attributed to the regulation of the intestinal microbiota composition and promotion of SCFAs secretion.