Challenges and insights in detecting early inflammation in DSS-induced colitis using chemiluminescence

Ulcerative colitis (UC) is a complex inflammatory condition with limited non-invasive tools to monitor early-stage inflammation. This study aimed to investigate the early stages of inflammation in acute and chronic murine models of dextran sulfate sodium (DSS)-induced colitis using in vivo and ex vivo chemiluminescence imaging.

Two DSS-induced colitis models were used: an acute model over 7 days and a chronic model over 6 weeks. Body weight, stool consistency, and fecal occult blood (FOB) tests were monitored. Chemiluminescence imaging was used to assess inflammation in vivo and ex vivo, complemented by colonoscopy in the chronic model.

In the acute model, DSS-treated mice exhibited weight loss, colon shortening, and positive FOB tests by day 7. Ex vivo chemiluminescence signals exhibited a significant increase as early as day 5 (p < 0.001), while in vivo imaging showed minimal changes. In the chronic model, periodic DSS exposure resulted in recurrent inflammation, with positive FOB tests and significantly elevated ex vivo and in vivo chemiluminescence signals during the final DSS cycle (p < 0.05). Colonoscopy confirmed inflammation progression.

This study demonstrates the progression of inflammation in acute and chronic colitis models. However, in vivo chemiluminescence imaging did not reliably detect the onset of inflammation, limiting its application for early-stage disease detection. Ex vivo chemiluminescence and FOB tests provided more consistent insights into inflammation dynamics, addressing the need for improved non-invasive monitoring tools in UC research.