ICA reduces intestinal damage and extends survival following TBI. (A-G) C57B6 WT or C57B6 IFN-αR^−/− mice were lethally irradiated (11 Gy) without subsequent BMT. Control animals were not irradiated (NRC, no radiation control). Mice received daily oral gavage with 150 mg/kg ICA or vehicle (VEH) starting 1 day prior to irradiation. Representative data from 2 experiments. (A) Kaplan-Meier survival curve (NRC, n = 5; VEH and ICA, n = 10). (B) Severity of diarrhea (day 3 postirradiation) (NRC, n = 5; VEH and ICA, n = 10). (C) Quantitation of CFU per gram MLN (day 3 postirradiation) (NRC, n = 5; VEH and ICA, n = 9). (D) Villus height (distal ileum, day 3 postirradiation) measured in H&E-stained sections (NRC, n = 3; VEH and ICA, n = 5). (E) H&E staining of distal ileum on day 3 postirradiation. Typical villus height measurements are indicated by yellow lines. Images are ×200 magnification. (F) Regenerating crypt foci. Area of regenerating crypt foci were determined by measuring height and width of foci, as identified by H&E staining (n = 5 all groups). (G) H&E staining of distal ileum on day 4 postirradiation. Yellow lines represent typical height measurements of regenerating foci. Width measurements were determined similarly. Images are ×400 magnification. Statistics: Mantel Cox log-rank (survival curve) or Kruskal-Wallis ANOVA. ****P < .0001; ***P = .0001 to .001; **P = .001 to .01; *P = .01 to .05; ns, not significant.