Longitudinal PET/CT evaluation of TNBS-induced inflammatory bowel disease rat model

Abstract Inflammatory bowel disease (IBD) is a group of chronic disorders of the gastrointestinal tract, which two main types are Crohn’s disease and ulcerative colitis. It has multifactorial etiologies, being essential the use of animal models and disease activity measures to develop new therapies. With this aim, the use of animal models in combination with non-invasive molecular imaging can play an important role in the development of new treatments. In this study, IBD was induced in rats using 2,4,6-trinitrobenzenesulfonic acid (TNBS) and longitudinal [ 18 F]FDG PET/CT scans were conducted to assess disease progression post-TNBS administration. Afterwards, [ 18 F]FDG PET/CT scans were carried out after treatment with methylprednisolone to validate the model. In non-treated rats, SUV max (Standardized Uptake Value) rapidly increased after IBD induction, being particularly significant (p  max between days 7–13 (p  2  = 0.61) and strong (R 2  = 0.82) correlation of SUV max with Nancy grade (parameter for histological assessment of disease activity) and weight changes, respectively. In this study, we have performed the first longitudinal [ 18 F]FDG PET/CT assessment of TNBS-induced IBD in rats, demonstrating the potential role of preclinical molecular imaging for the evaluation of new therapies in combination with IBD rat models.