Schematic representation of AOM/DSS model (A). Significant increase, both in body weight loss (B) and DAI scores (C), are seen in SAMP compared to AKR mice following multiple DSS cycles. High-resolution endoscopy of distal colons was performed at 3 different time points post-AOM/DSS treatment, i.e., day 1, 33 and 56, and show signs of colitis and tumor progression following the first and second DSS cycle, particularly in SAMP mice. Increased colitis and tumorigenesis (D) are evident, based on endoscopic scores in SAMP relative to AKR mice. Furthermore, representative photomicrographs of colon sections of both AKR and SAMP mice with histologic scores (E) demonstrate that SAMP mice exhibit more severe colitis. Colon length was measured at the end of treatment (F) and results are presented as mean ± SEM; * P < 0.05, ** P < 0.01, *** P < 0.001; n = 12.