Figure 3.

Granulocyte-macrophage colony-stimulating factor–activated monocytes (GMaM) have a therapeutic effect in dextran sulfate sodium (DSS)-induced colitis in wild-type C57Bl/6 mice. (A) Chronic colitis induced by repeated oral administration of DSS in C57Bl/6 mice. One day before the start of the third treatment cycle, mice received either control monocytes, GMaM, or phosphate-buffered saline as vehicle. Body weight was monitored daily and is shown as the percentage of weight change of three independent experiments with C57Bl/6 mice (n = 7–15 per treatment group). (B) On day 21, colons were removed, and the colon lengths were measured for each treatment group. Graphs show the mean ± standard error of the mean (SEM). (C) Murine endoscopic index of colitis severity (MEICS) scores (mean ± SEM) based on high-resolution colonoscopy. (D) Proinflammatory cytokines (interleukin 1β = white bars, tumor necrosis factor α = black bars) were measured in DSS-treated and healthy control C57Bl/6 mice by quantitative reverse-transcription polymerase chain reaction in distal colon biopsies taken at the end of the experiment. Mean ± SEM for three independent experiments (n = 11 per treatment group). (E) Colon inflammation scores (mean ± SEM) were graded by two blinded investigators and performed for the proximal and the distal part of the colon separately (n = 11). (F) Representative pictures of chronic colitis in C57Bl/6 mice on day 20 for two independent experiments are shown (arrow shows fibrin plaque; n = 11 per treatment group). (G) Representative microscopic colon images of mice with colitis and healthy control mice are shown (H&E and CD11b staining; scale bar: 100 μm). Statistical significance was determined by unpaired Student t test except for body weight change where two-way analysis of variance with Bonferroni correction was used. *P < .05; **P < .01; ***P < .001.