Fig. 5.

Sox9-EGFP Low ISCs expand during crypt regeneration following radiation. A: hematoxylin and eosin (H&E) staining of jejunum from nonirradiated (NI) and irradiated mice at days 3, 4, 5, 7, and 9 after 14 Gy abdominal irradiation demonstrates crypt loss at day 3, formation of regenerating microcolonies at day 4; crypt hyperplasia at days 5 (D5) and 7 (D7) and a trend toward baseline crypt and villus morphology by day 9. Scale bar 100 μm. B: immunostaining for Sox9-EGFP (green) and ChgA (yellow) demonstrates that regenerating microcolonies and hyperplastic crypts are highly enriched in Sox9-EGFP Low cells whereas Sox9-EGFP High cells colabeled with ChgA did not expand after radiation (nuclei staining, DAPI, blue; confocal images; scale bar 25 μm). C: histogram shows means ± SE for the number of Sox9-EGFP High or Low cells per crypt section. At least 30 crypt sections were analyzed per animal by 3 independent blinded observers (n ≥ 3 independent mice at each time point; ^aP < 0.001 vs. nonirradiated; ^bP < 0.001 vs. day 5; ^cP < 0.05 vs. day 9).