# Comparable efficacy and mechanisms of sterile soil ingestion versus low hygiene exposure in DSS-induced colitis

## TL;DR

Sterile soil ingestion and low-hygiene environments similarly help reduce colitis in mice by improving gut bacteria and reducing inflammation.

## Contribution

This study shows that sterile soil ingestion is as effective as low-hygiene exposure in treating colitis through gut microbiota modulation.

## Key findings

- Both sterile soil ingestion and low-hygiene exposure reshape gut microbiota and alleviate colitis symptoms in mice.
- Sterile soil ingestion increases butyric acid, while low-hygiene exposure increases acetic acid in feces.
- Both interventions restore intestinal barrier integrity and reduce pro-inflammatory cytokines.

## Abstract

Accumulating evidence suggests that exposure to low-hygiene environments (LHE) can alleviate chronic diseases by modulating the gut microbiota. Soil has been identified as a key factor in shaping microbial communities within the LHE. Furthermore, influenced by cultural customs and traditions, the practice of soil ingestion persists in many regions worldwide, serving both nutritional and medicinal purposes. However, whether soil confers efficacy comparable to that of LHE exposure or which intervention demonstrates better efficacy remains unexplored. This study compared the interventional effects and underlying mechanisms of sterile soil ingestion versus LHE exposure in dextran sulfate sodium (DSS)-induced chronic ulcerative colitis (UC) mice. Our results demonstrated that UC mice exhibited significant gut dysbiosis, characterized by reduced microbial diversity and disruption of microbial network structure. Both LHE exposure and soil ingestion markedly reshaped the gut microbial ecosystem, exhibiting highly similar regulatory patterns in microbial composition. LHE exposure increased fecal acetic acid concentrations, while soil ingestion elevated butyric acid levels. Moreover, both interventions effectively alleviated UC clinical symptoms, restored intestinal barrier integrity, and downregulated pro-inflammatory cytokine levels. In summary, sterile soil ingestion and LHE exposure exert comparable protective effects in UC mice. Given its operational simplicity and feasibility, sterile soil represents a promising translation and application. These findings support the potential of sterile soil as a practical therapeutic approach for alleviating UC-related gut ecological disruption in modern urban settings.

Urbanization and excessive hygiene have reduced human exposure to soil and environmental microorganisms, contributing to the rising incidence of immune-related disorders such as inflammatory bowel disease. This study demonstrates that sterile soil ingestion and low-hygiene environment exposure comparably reshape the gut microbiota, enhance short-chain fatty acid production, and alleviate colitis in mice. These findings highlight sterile soil as a practical and controllable intervention to mimic the protective benefits observed in traditional, microbe-rich environments. Given the challenges of accessing low-hygiene settings in modern urban life, sterile soil represents a feasible therapeutic approach to alleviate gut dysbiosis and inflammation, with broad implications for microbiome-based therapeutics in industrialized societies.