Ex-vivo magnetic resonance elastography detects inflammation-associated biomechanical changes in a mouse model of Salmonella-induced colitis

Abstract Inflammation alters the mechanical properties of soft tissues, yet the biomechanics of the inflamed intestine remain poorly characterized. Using magnetic resonance elastography (MRE), we characterized colonic biomechanical properties in a murine colitis model. CBA/J mice infected with Salmonella Typhimurium were sacrificed at days 5, 16 and 30 post infection alongside uninfected controls. Ex-vivo tabletop MRE and the Springpot model yielded shear modulus µ (stiffness) and powerlaw exponent α (structure). Collagen, hyaluronic acid and periostin content, immune-cell infiltration, epithelial apoptosis and histopathological scoring were assessed histologically. Colonic stiffness decreased at day 5 (1.7 ± 0.7 kPa) versus controls (5.5 ± 4.0 kPa; p = 0.0002), concurrent with development of edema, immune-cell infiltration and apoptosis, without concomitant ECM changes. Stiffness normalized by day 30 and correlated negatively with the histopathological score ( r = − 0.40, p = 0.002) and the total cell count ( r = -0.47, p = 0.002). At day 5, µ discriminated infected from control colons with an AUC of 0.93 (sensitivity 89%, specificity 90%). Ex-vivo MRE thus detects reversible, inflammation-driven biomechanical changes, indicating that MRE-derived stiffness may serve as a biomechanical readout of acute intestinal inflammation.