Fig. 4

Loss of CD47 in IEC results in impaired recovery from DSS-induced colitis. Age- and sex-matched Cd47^ΔIEC and tamoxifen-treated Cd47^ERΔIEC mice were treated with three consecutive cycles of 2.5% DSS in drinking water for either 4 days (Cd47^ΔIEC) or 3 days (Cd47^ERΔIEC), followed by 5 days of water recovery. Cd47^ERΔIEC mice were treated with DSS 2 weeks after tamoxifen treatment. a–b Disease activity index scores are represented as an average of scores 0–4 for percent weight loss, stool consistency, and presence of blood in stools. Cyclical treatment of a Cd47^ΔIEC and b tamoxifen-treated Cd47^ERΔIEC mice with 2.5% DSS in drinking water, followed by a plain water recovery period, induced greater DAI scores in the absence of epithelial CD47. Data are representative of two independent experiments with 5–6 mice per group and are expressed as means ± SEM. a *p = 0.02, b *p = 0.036 by two-way ANOVA. c Histological scoring of hematoxylin and eosin (H&E)-stained tissue sections of colonic mucosa: percentage of injury/ulceration represents a ratio of the length of injured/ulcerated areas (≥ 50% crypt loss) relative to the entire colon length, as assessed in Swiss roll mounts of the entire colon. Results indicate greater damage in the absence of epithelial CD47. Points represent individual mice. Data are representative of two independent experiments with 5–6 mice per group and are expressed as means ± SEM. Significance determined by two-tailed Student’s t test. *p = 0.016, ***p = 0.001. d, e Representative H&E staining of colon tissue sections after three cycles of DSS/water revealed extensive crypt destruction in distal colon of Cd47^ΔIEC and Cd47^ERΔIEC mice. Large areas of ulcerated mucosa with granulocytic infiltrates were present in the mid colon in Cd47^ΔIEC and Cd47^ERΔIEC mice, in comparison with littermate controls. Scale bars = 100 μm upper panels, 300 μm lower panels. Results are representative of at least two independent experiments with 5–6 mice per group. Source data are provided as a Source Data file