Transient colitis induces neurogenesis, contributing to structural remodeling of the myenteric plexus. (A) Percentage of total viable cells (left) and absolute cell counts (right) of colonic muscularis CD45^–CD90⁺CD24⁺ neurons in 3×DSS- or water-treated WT mice, quantified by FC (control, n = 5–7; DSS, n = 4–7). (B) Experimental design used in D: 3×DSS (2.15%) was given with the tamoxifen (Tam) regimen as shown. In C, only 1×DSS was given with the same tamoxifen regimen. (C) Confocal images of colonic myenteric plexus isolated from tamoxifen- and 1×DSS-treated Nes^ER-CreRosa26(R26)-STOP^fl/fltdTomato (Cre⁺+Tam/DSS) and control R26-STOP^fl/fltdTomato (Cre^– +Tam/DSS) mice, as well as untreated Nes^ER-CreR26-STOP^fl/fltdTomato (Cre⁺) mice on day 45 (6.5 wk), stained with antibodies to Hu (neuronal somas), tdTomato (newborn cells), and βIII-tubulin (nerve fibers). Scale bars, 100 μm. (D) Confocal images of colonic myenteric plexus from tamoxifen- and 3×DSS- or water-treated Nes^ER-CreR26-STOP^fl/fltdTomato (Cre⁺) mice at week 1 and 10 after starting DSS, stained with Hu, tdTomato, and βIII-tubulin antibodies. Images are representative of control (n = 3–6) and DSS (n = 4–6) for each time point. Scale bars, 100 μm. (E) Percentage of tdTomato⁺Hu ⁺ neurons in the colonic myenteric plexus from Cre⁺ mice described in D at week 10, based on confocal microscopy (n = 6 per group). Data represent the mean ± SEM of 5–10 fields of view analyzed per mouse per group. (F) Percentage of newly generated tdTomato⁺ cells among CD45^–CD90⁺CD24⁺ colonic myenteric neurons isolated from mice described in D, quantified by FC (control, n = 3–6; DSS, n = 4–6). Week 10 data are from the same mice as in D. All graphs show the mean ± SEM, n—mouse. Data are representative of at least two independent experiments with similar results. Statistical analyses: multiple t test (A), unpaired Student’s t test (E and F), *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, and ****P ≤ 0.0001.