肠道菌群在高原低氧肠道损伤中的作用研究

目的　探讨肠道菌群在高原低氧环境中参与肠道损伤的作用机制。 方法　将20只C57 BL/6小鼠按1：1比例随机分为对照组和暴露组，建立6000 m高原低氧模型，造模成功后收集两组小鼠粪便、血液和近端结肠组织。采用16S rDNA测定粪便中肠道菌群结构；检测小鼠血液生化指标；HE和PAS染色观察结肠肠道黏膜结构的改变；RT-qPCR测定结肠组织ZO-1、Occludin、IL-6和TNFα的mRNA表达水平。 结果　与对照组相比，暴露组小鼠血细胞、血红蛋白和红细胞压积值显著升高，高原低氧模型建模成功；16 SrDNA结果显示肠道菌群紊乱、多样性下降，黏蛋白降解菌艾克曼菌，普雷沃氏菌、梭状芽胞杆菌XVIII等致病菌含量上升，短链脂肪酸产生菌罗斯氏菌、Odoribacter菌、Lachnospiracea菌、Butyricicoccus菌和欧氏菌等益生菌含量下降；HE和PAS染色结果显示结肠组织上皮连续性中断、腺体萎缩、隐窝变短、杯状细胞数量减少，提示肠道结构损伤且黏膜屏障破坏；结肠组织紧密连接蛋白Occludin和 ZO-1 mRNA表达水平下降，进一步暴露组小鼠肠道黏膜受损，炎症因子IL-6和TNFα 的mRNA表达量上升，可能与肠道炎症反应有关。 结论　高原低氧环境导致的肠道损伤可能与肠道菌群改变有关。肠道菌群紊乱、多样性下降，致病菌相对丰度上升，益生菌相对丰度下降，菌群的这些改变造成肠道黏膜损伤，引起肠道炎症，进而出现肠道损伤，最终导致高原肠道相关疾病。

Effects of gut microbiota on intestinal damage in high-altitude hypoxia

Objective　To explore the mechanism of gut microbiota in intestinal damage in high-altitude hypoxic environment. Methods Twenty C57BL/6 mice were randomly divided into a control group and an exposure group according to the ratio of 1:1. After the successful modeling of the 6000-meter high-altitude hypoxia model, the feces, blood and proximal colon tissue of these two groups were collected. The structure of gut microbiota in feces was determined by 16S rDNA analysis. The blood biochemical indexes were detected. The pathological changes of intestinal mucosal structure were observed by HE and PAS staining. The mRNA expression levels of ZO-1, Occludin, IL-6 and TNFα of colon tissue were measured by RT-qPCR. Results Compared with the control group, the red blood cell, hemoglobin and hematocrit values of the exposure group significantly increased. The high-altitude hypoxia model was successfully established. The 16S rDNA showed that the gut microbiota was disordered and the diversity declined, the content of the mucin-degrading bacteria Akkermansia and pathogenic bacterias Clostridium XVIII, Prevotella increased, the relative content of the short-chain fatty acids producing bacteria Roseburia, Odoribacter, Lachnospiracea, Butyricicoccus and Olsenella decreased. HE and PAS staining results showed that the interruption of colon epithelial continuity, atrophy of glands, shortening of crypts and reduction of goblet cells, which indicated the damage of intestinal structure and mucosal barrier. The expression levels of tight junction protein Occludin and ZO-1 mRNA decreased, which confirmed the disruption of intestinal mucosal of the exposure group. The expression level of inflammatory factors IL-6 and TNFα increased, which may be related to intestinal inflammatory reaction. Conclusions The intestinal damage caused by high-altitude hypoxic environment may be related to the change of gut microbiota. Gut microbiota disorder and diversity decreased, the relative abundance of pathogenic bacteria increased and probiotics decreased. These alterations cause the intestinal mucosal damage, intestinal inflammation, intestinal damage, and finally lead to high-altitude intestinal related diseases.