Quantitative Phenotyping of Inflammatory Bowel Disease in the IL-10-deficient Mouse by Use of Noninvasive Magnetic Resonance Imaging

BACKGROUND: Although magnetic resonance imaging (MRI) is an increasingly used diagnostic tool in the assessment of inflammatory bowel disease (IBD) in humans, diagnosis and quantitation of intestinal inflammation in animal models of IBD still depends on ex vivo techniques. The aim of this study was to evaluate whether high-field MRI is suitable for the quantitative phenotyping of gut inflammation in a dextran sulfate sodium (DSS)-triggered interleukin (IL)10-deficient (IL-10(-/-)) mouse model of IBD, especially in longitudinal studies. METHODS: Using colitis-susceptible and -resistant backgrounds, MRI and ex vivo analyses were applied to characterize this specific model, differentiating disease severity and time-dependent alterations. Colon wall thickness, cecum wall tissue intensity, spleen, and mesenteric lymph node (MLN) volumes were evaluated 1, 2, 4, and 12 weeks after disease onset by T2-weighted MRI. Ex vivo parameters included histology, spleen, and MLN weight and analysis of cytokine expression. RESULTS: MRI and ex vivo determined parameters correlated well, revealing a mouse strain-specific colitis development over time with characteristics typical for the DSS model in the initial and for the IL-10(-/-) model in the chronic phase. To evaluate the use of high-field MRI for monitoring therapeutic studies, mice with a profound colitis were treated with IL-10-producing Saccharomyces boulardii and monitored by MRI. CONCLUSIONS: MRI can be utilized to quantify colitis development in the IL-10(-/-) model of IBD. Therefore, this noninvasive technique might be highly advantageous for an individual follow-up of colitis development in chronic models of IBD, facilitating the reduction of animal numbers in this kind of research.