λ-卡拉胶诱导的肠道菌群紊乱对小鼠糖代谢的影响

Influence of λ-Carrageenan Induced Gut Microbiota Disorder on Glucose Metabolism of Mice

卡拉胶是常见的食品添加剂,但人们对其改变肠道菌群结构的作用提出了疑问。以低、中、高剂量(1.7、8.3、41.7 mg/kg)的λ-卡拉胶持续灌胃小鼠C57BL/6 12周,通过检测小鼠的葡萄糖耐受性、胰岛素抵抗和肠道菌16S rDNA序列,探究λ-卡拉胶对小鼠糖代谢及肠道菌群的影响。借助粪菌移植技术验证肠道菌群在λ-卡拉胶影响小鼠糖代谢中发挥的作用。研究结果表明,摄入不同剂量的λ-卡拉胶均可使小鼠出现体质量增长率减少、空腹血糖水平升高以及胰岛素抵抗的症状。肠道菌群分析结果表明:λ-卡拉胶可使肠道菌群丰度及结构发生显著变化;在门水平,摄入λ-卡拉胶使厚壁菌门(Firmicutes)菌群的丰度上升,拟杆菌门(Bacteroidota)菌群的丰度下降;在属水平,摄入λ-卡拉胶使调控血糖的Bacteroidales_S24-7_group_norank丰度降低、与脂代谢及体质量降低有关的乳杆菌属(Lactobacillus)和毛螺菌属(Lachnospira)丰度升高、与肠道黏液层降解相关的阿克曼氏菌属(Akkermansia)的丰度显著升高。粪菌移植的结果显示,移植灌胃λ-卡拉胶小鼠粪菌同样使小鼠出现代谢紊乱的症状。研究结果表明,摄入λ-卡拉胶尤其是高剂量λ-卡拉胶可扰乱肠道菌群结构,从而诱导小鼠糖代谢紊乱。

Carrageenan is a common food additive,but its effect on changing the structure of gut microbiota was questioned.In this study,the C57BL/6 mice were given three dosages ofλ-carrageenan,including low,medium and high dose(1.7,8.3,41.7 mg/kg)for 12 weeks.The effects ofλ-carrageenan on glucose metabolism and gut microbiota in mice were investigated by glucose tolerance test,insulin tolerance test and gut microbiota 16S rDNA sequencing.And the role of gut microbiota in the effect ofλ-carrageenan on glucose metabolism in mice was verified by fecal bacteria transplantation experiments.The results showed that intake of different doseλ-carrageenan could cause the symptoms of metabolic disorders in mice,such as decreased body weight gain,elevated fasting blood glucose and insulin resistance.By the analysis of gut microbiota composition,it was found thatλ-carrageenan could significantly affect the abundance and structure of gut microbiota.At the phylum level,λ-carrageenan increased the relative abundance of the Firmicutes and reduced the relative abundance of Bacteroidota.At the genus level,the abundance of Bacteroidales_S24-7_group_norank was reduced,which regulated blood glucose.The abundance of Lactobacillus and Lachnospira related to lipid metabolism and weight loss was increased byλ-carrageenan administration.And it significantly increased abundance of Akkermansia,which is related to the degradation of the intestinal mucus layer.In addition,the results of fecal bacteria transplantation showed that the metabolic disorders appeared in fecal transplant mice were consistent with those ofλ-carrageenan gavage mice.The results showed that intake ofλ-carrageenan,especially high doses ofλ-carrageenan,induced metabolic disorders in mice by interfering with the composition of the gut microbiota.