Soil causes gut microbiota to flourish and total serum IgE levels to decrease in mice

Abstract

BackgroundTraditional farm environments provide protection from allergic diseases. In this study, farm environmental factors were classi ed into three categories: environmental microbes, soil, and organic matter. To explore the impact of soil and environmental microorganisms on gut microbiota and immune function, mice were fed sterilized soil, soil microbes (in lieu of environmental microbes), or non-sterilized soil. ResultsMetagenomic sequencing results showed that the intake of sterile soil while inhaling a small amount of soil microbes in the air, increased gut microbial diversity and the abundance of type III secretion system (T3SS) genes and decreased total serum IgE levels induced by 2-4-dinitro uorobenzene. The intake of soil microbes increased the abundance of genes involved in the metabolism of short-chain fatty acids and amino acid biosynthesis. By contrast, the intake of soil increased gut microbial diversity, the abundance of T3SS genes and related infectious elements, and genes associated with the metabolism of short-chain fatty acids and amino acid biosynthesis and decreased serum IgE levels. The immune function was positively and signi cantly correlated with the bacterial secretion system genes, especially with that of T3SS. ConclusionsAn important mechanism through which farm environments exert a protective effect against allergic diseases could be by serving as a "prebiotic" promoting the reproduction and growth of some intestinal microorganisms that harbor bacterial secretion system genes, especially those of T3SS, whose abundance was positively and signi cantly correlated with innate immune function of mice.

Soil intake modifies the gut microbiota and alleviates ovalbumin-induced mice asthma inflammation

“…Soil ingestion altered the gut microbial composition in asthmatic mice, but no increase in intestinal microbial diversity or richness was found, which is inconsistent with the findings by Zhou et al(16). Presumably, this may be due to the influence of stress.…”

“…Sterilized soil (5 g) and standard feed (95 g) were weighed and then mixed with sterilized water on a super-clean bench. See Table S3 for a detailed soil composition analysis (16).…”

“…Our previous study indicated that soil is a crucial factor in shaping intestinal microecology and that exposing mice to sterilized soil significantly changed the gut microbial composition (15). Furthermore, ingestion of sterilized soil, while inhaling microbes in the air, reduced serum IgE levels by increasing gut microbial diversity (16). However, it is unknown if sterilized soil intake as prebiotics can achieve a therapeutic effect against ovalbumin (OVA)-induced asthma by changing intestinal microbiota.…”

Soil intake modifies the gut microbiota and alleviates Th2-type immune response in an ovalbumin-induced asthma mouse model

“…Our previous soil analysis results indicate that there is no heavy metal contamination. 16 The area has never been planted with crops, hence chemical substances such as herbicides or pesticides have not been used. Additionally, there are no chemical factories surrounding the farm; thus there is also no presence of organic pollutants.…”

“… 15 Furthermore, ingestion of sterilized soil, while inhaling microbes in the air, reduced serum IgE levels by increasing gut microbial diversity. 16 However, it is unknown whether the intake of sterilized soil as a prebiotic can achieve a therapeutic effect against ovalbumin (OVA)-induced asthma by changing the intestinal microbiota.…”