Figure 4
CHIR99021 protects mice from radiation-induced lethal GI injury.
WT C57BL/6 mice were injected intraperitoneally with CHIR99021 (2 mg/kg) or vehicle (dimethyl sulfoxide) 4 h prior to 14.5 Gy ABI (A) or 15 TBI (B-G). (A) Survival curves of mice after ABI. n = 10 mice in each group. (B) Apoptosis in the intestinal crypts 4 h after TBI was assessed by TUNEL staining (brown). Left, representative pictures of TUNEL staining. Right, quantitation of TUNEL index. (C) Representative pictures and quantitation of p-H2AX staining in the intestinal crypts 4 h and 24 h after TBI. (D) Representative pictures of regenerated crypts identified by BrdU staining 96 h after TBI (brown). (E) Quantitation of regenerated crypts (left) and villus height (right) in D. (F) TUNEL staining in the crypts of Lgr5-EGFP;Cre-ER mice 4 h after TBI. Left, representative pictures of TUNEL (green), Lgr5 (red) and nuclei (DAPI) staining. Right, quantitation of Lgr5+ crypts containing one or more TUNEL+ cells. (G) Expression of Olfm4, Lgr5, CD44, Bmi1 and Hopx transcripts was analyzed by real-time RT-PCR. (B-G), values are means ± SD, n = 3 mice in each group. ***P < 0.001, **P < 0.01, *P < 0.05. Scale bar, 25 μm.
