Magnetic Resonance Colonography for Fibrosis Assessment in Rats with Chronic Colitis

Abstract

BackgroundMagnetic resonance colonography (MRC) has been developed to assess inflammatory bowel diseases. We aimed to assess the feasibility of MRC in rats with TNBS-induced chronic colitis and to confront imaging results with fibrosis and stenosing features of the model.Materials and MethodsChronic colitis was induced in 12 rats by weekly intra-rectal injection of increasing doses of TNBS for 6 weeks, while 8 control rats received the vehicle. At week 7, MRC was performed. Fibrosis scores were assessed and fibrosis mediators measured.ResultsChronic colitis was associated with significant body weight loss (p<0.0001) and higher colon weight/length compared to controls (p = 0.0004). Fibrosis mediators and histological scores were significantly higher in rats with TNBS than in controls: α-SMA expression (0.9 versus 0.61, p = 0.0311) and fibrosis score (p = 0.0308). Colon wall thickness was higher in rats with TNBS than in controls: maximal thickness (2.38 versus 0.74 mm, p<0.0001) and minimal thickness (1.33 versus 0.48 mm, p<0.0001). Wall signal intensity on T2w images was higher in rats with TNBS than in controls (9040 versus 6192, p = 0.0101) and correlated with fibrosis score (r = 0.5214; p = 0.04). Luminal narrowing was higher in rats with TNBS (50.08 versus 10.33%, p<0.0001) and correlated with α-SMA expression (r = 0.5618; p = 0.01). Stenosis was observed in 7/9 rats with TNBS and in no controls (p = 0.0053).ConclusionsMRC is feasible and easily distinguishes rats with colitis from controls. MRC signs correlated with fibrosis parameters. MRC evaluation may be part of a new anti-fibrosis drug assessment in experimental models of chronic colitis.

Noninvasive Longitudinal Study of a Magnetic Resonance Imaging Biomarker for the Quantification of Colon Inflammation in a Mouse Model of Colitis

“…Similarly, in a small number of scientific articles, MRI was shown to be a promising instrument to study inflammation in IBD animal models through the measurement of colon wall thickening [31][32][33][34] or colon wall signal intensity, 31,33,34 often in conjunction with contrast agents. 29,32,[39][40][41][42] Nonetheless, the sensitivity, robustness, and reproducibility of MRI measurements have not yet been evaluated in small laboratory animals.…”

“…It can be used to measure colon wall thickness, edema, and increased perfusion/leakage in IBD models. [28][29][30] A few previous works [31][32][33][34] were able to show that MRI can be used to measure colon wall thickness in small rodents at selected time points and that this parameter correlates with blood or ex vivo markers of inflammation. In this work, we aim at pushing their investigations further to evaluate the potential of colon wall thickness measured using MRI as an in vivo imaging biomarker of inflammation for IBD in an animal model of this disease.…”

SPECT-computed tomography in rats with TNBS-induced colitis: A first step toward functional imaging

“…Nevertheless, COX-2 is involved in angiogenesis processes and chronic inflammation and be more relevant in chronic colitis assessment. Indeed, we have previously shown that MRC criteria were associated with COX-2 expression in rats with chronic TNBS-induced colitis[14]. Evaluation of correlation between SPECT criteria and colon COX-2 expression required further evaluation in rats with chronic colitis.…”

“…The 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model is a reference acute colitis models with transmural inflammation close in some regards to those observed in CD[11,12]. We previously validate the use of MRI to assess inflammation and fibrosis in colitis models[13,14]. We now aim to evaluate the SPECT to assess inflammation.…”

Assessment of colon and bladder crosstalk in an experimental colitis model using contrast‐enhanced magnetic resonance imaging

“…Magnetic resonance imaging (MRI) methodology has been previously used to assess TNBS-induced colitis [2,4,5]. However, only a few reports have established that there is colon-bladder crosstalk associated with IBD, particularly involving shared neural pathways [6,7].…”