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

摘要

AIM 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.METHODS 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 andmaximal wall signal intensity. Laboratory parameters were assessed: colon weight:length ratio, colon cyclooxygenase-2 expression by western blot and histological inflammatory score.RESULTS 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).CONCLUSION SPECT-CT is feasible and easily distinguished control from colitic rats.