Fig. 2.

The abnormal response to MDP in SAMP mice is contained within the hematopoietic compartment. AKR and SAMP mice (n = 9 per group) were transplanted with SAMP and AKR BM, respectively (n = 5 per group), and administered MDP or PBS during the first 3 d of 3% DSS treatment. (A) Percentage survival of chimeric mice during 3% DSS treatment. (Log-rank test, hazard ratio for AKR→SAMP with DSS/PBS was 4.85 times higher than for DSS/MDP, 95% confidence interval (CI) of hazard ratio = 0.8, 26.7, P = 0.090; no effect on hazard ratio for SAMP→AKR, P = 1.0.) (B) Colonic total inflammatory scores, as determined by the sum of chronic inflammation, active inflammation, percentage reepithelialization, and percentage of ulceration. (C) Representative histopathological sections for colons in each chimeric group. AKR BM→SAMP mice treated with MDP showed more attenuated intensity of colitis and active inflammation compared with control (PBS treatment); no difference were seen in SAMP BM→AKR mice treated with MDP or PBS, as well as SAMP BM→SAMP mice treated with MDP or PBS, all of which showed severe ulceration with severe active and chronic inflammation. AKR BM→AKR mice showed no ulceration and mild active and chronic inflammation with some regenerative changes in the group treated with MDP compared with control (PBS). (Scale bars, 100 µm.) Data are represented as mean ± SEM. The asterisks (*) denote significant differences at P < 0.05. Results are representative of three independent experiments.