Published online Jan 14, 2017. doi: 10.3748/wjg.v23.i2.216
Peer-review started: July 13, 2016
First decision: August 29, 2016
Revised: September 6, 2016
Accepted: September 28, 2016
Article in press: September 28, 2016
Published online: January 14, 2017
Processing time: 184 Days and 16.2 Hours
To assess the feasibility of SPECT-computed tomography (CT) in rats with trinitrobenzene sulfonic acid (TNBS)-induced acute colitis and confront it with model inflammatory characteristics.
Colitis was induced in Sprague-Dawley rats by intrarectal injection of TNBS (n = 10) while controls received vehicle (n = 10). SPECT-CT with intravenous injection of 10 MBq of 67Ga-Citrate was performed at day 2. SPECT-CT criteria were colon wall thickness and maximal wall signal intensity. Laboratory parameters were assessed: colon weight:length ratio, colon cyclooxygenase-2 expression by western blot and histological inflammatory score.
Colon weight/length ratio, colon COX-2 expression and histological inflammatory score were significantly higher in the TNBS group than in the control group (P = 0.0296, P < 0.0001, P = 0.0007 respectively). Pixel max tend to be higher in the TNBS group than in the control group but did not reach statistical significance (P = 0.0662). Maximal thickness is significantly increased in the TNBS group compared to the control group (P = 0.0016) while colon diameter is not (P = 0.1904). Maximal thickness and colon diameter were correlated to colon COX-2 expression (P = 0.0093, P = 0.009 respectively) while pixel max was not (P = 0.22). Maximal thickness was significantly increased when inflammation was histologically observed (P = 0.0043) while pixel max and colon diameter did not (P = 0.2452, P = 0.3541, respectively).
SPECT-CT is feasible and easily distinguished control from colitic rats.
Core tip: Transsectional imaging such as magnetic resonance imaging are emerging to evaluate colonic inflammation but they do not allowed inflammation quantification. Functional imaging by SPECT-computed tomography (CT) could be interesting under quantification. This present study validates the use of SPECT in colitis models. We confronted SPECT-CT parameters to lab parameters and we found that maximal thickness was correlated to inflammatory parameters such as colon COX-2 expression or histological inflammatory score. Evaluating animal models may be important an important tool for preclinical studies in inflammatory bowel diseases models. It also allows optimizing the technique prior to patient contact.