Li Na, Li Mengjie, Zhang Honglin, Bai Zhimao, Fei Zhongjie, Dong Yangyang, Zhang Xinting, Xiao Pengfeng, Sun Xiao, Zhou Dongrui
Key Laboratory of Child Development and Learning Science of Ministry of Education, Southeast University, Nanjing, China.
College of Food Science, Nanjing Xiaozhuang University, Nanjing, China.
Appl Environ Microbiol. 2025 Apr 23;91(4):e0247724. doi: 10.1128/aem.02477-24. Epub 2025 Mar 6.
Changes in diet, cleanliness, stress, and exercise patterns may contribute to the disappearance of various gut microbes in humans who relocate to developed countries from developing countries. To explore the impact of environmental cleanliness on the gut microbiota, adult mice housed in a general animal room were divided into three groups. The control group was subjected to an unchanged living environment, SPF mice were moved to a specific pathogen-free (SPF) animal room with higher environmental cleanliness, and SPFL (specific pathogen-free specific with a fecal leakage grid) mice were moved to the SPF animal room and reared in cages with the function of preventing mice from eating feces as much as possible. Metagenome sequencing results showed that the gut microbial diversity decreased after the environmental change, accompanied by a substantial loss in gut microbiota, including genera known to have protective effects against allergies and those involved in short-chain fatty acid production. Additionally, the abundance of functional genes involved in short-chain fatty acid metabolism, amino acid synthesis, vitamin metabolism, flagellar assembly, and bacterial chemotaxis decreased. The environmental hygiene improvement also resulted in significant increases in total serum IgE, IL-4, IL-5, and IL-13 levels in mice with artificially induced chronic inflammatory dermatosis. Compared with SPF mice, preventing mice from eating feces as much as possible decreased the gut microbial diversity but did not markedly change functional gene expression or total serum cytokine levels.
Research has indicated that the human gut microbial diversity gradually decreases, while the prevalence of allergic diseases increases after movement from developing countries to developed countries. A healthy gut microbiota is necessary for proper human immune function. Movement from undeveloped to developed regions is often accompanied by an increase in environmental cleanliness. However, whether changes in environmental cleanliness are an important factor contributing to the decreased gut microbial diversity and increased prevalence of allergic diseases has not been reported. This study demonstrates the impact of increased environmental cleanliness on gut microbiota and susceptibility to allergic diseases and contributes to a better understanding of the increased incidence rate of various chronic diseases.
饮食、清洁程度、压力和运动模式的改变，可能导致从发展中国家移居到发达国家的人群中各种肠道微生物消失。为了探究环境清洁度对肠道微生物群的影响，将饲养在普通动物房的成年小鼠分为三组。对照组的生活环境不变，无特定病原体（SPF）小鼠被转移到环境清洁度更高的无特定病原体动物房，而SPFL（带有粪便渗漏网格的无特定病原体小鼠）小鼠被转移到SPF动物房，并饲养在尽可能防止小鼠食粪的笼子里。宏基因组测序结果表明，环境变化后肠道微生物多样性降低，同时肠道微生物群大量减少，包括已知对过敏有保护作用的菌属以及参与短链脂肪酸产生的菌属。此外，参与短链脂肪酸代谢、氨基酸合成、维生素代谢、鞭毛组装和细菌趋化作用的功能基因丰度降低。环境卫生改善还导致人工诱发慢性炎症性皮肤病的小鼠血清总IgE、IL-4、IL-5和IL-13水平显著升高。与SPF小鼠相比，尽可能防止小鼠食粪会降低肠道微生物多样性，但不会显著改变功能基因表达或血清总细胞因子水平。
研究表明，从发展中国家移居到发达国家后，人类肠道微生物多样性逐渐降低，而过敏性疾病的患病率增加。健康的肠道微生物群对人类正常免疫功能至关重要。从不发达地区迁移到发达地区往往伴随着环境清洁度的提高。然而，环境清洁度的变化是否是导致肠道微生物多样性降低和过敏性疾病患病率增加的重要因素尚未见报道。本研究证明了环境清洁度提高对肠道微生物群和过敏性疾病易感性的影响，有助于更好地理解各种慢性病发病率上升的原因。
