Early acidification of stool and urine as a simple noninvasive screening tool for ulcerative colitis activity

© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )

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Abstract

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent inflammation of the colon. The absence of simple, noninvasive, and early biomarkers for disease onset and progression remains a major clinical challenge. This study aimed to evaluate the potential of pH values in biological samples as noninvasive indicators for the early disease-related changes in an experimental rat model of UC. Experimental colitis was induced in rats by administering dextran sulfate sodium, and the results were compared to those of healthy controls. Disease progression was monitored by evaluating disease severity scores and histopathological changes. Throughout the experimental period, stool and urinary pH were measured daily, while colonic and serum pH were assessed post-mortem. As the experiment progressed, the colitic rats exhibited marked weight loss and severe inflammatory changes in the colon. Despite the worsening disease, no significant alterations were observed in colonic or serum pH. In contrast, both stool and urinary pH values significantly decreased during the early phase of experimental colitis. However, these pH fluctuations did not consistently correlate with UC severity. In conclusion, our findings suggest that stool and urinary pH represent promising, noninvasive biomarkers for the early detection and monitoring of disease activity in UC.

Keywords

Stool

Ulcerative colitis

Urine

Rat

Funding

This study was supported by a Grant-in-Aid for Academic Research Promotion from Kyoto Tachibana University (2025-5).

Conflict of interest

The authors declare that they have no competing interests.

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