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Updated: Jul 15, 2026
Intestinal Epithelial Regeneration in Response to Ionizing Irradiation
Published on: July 27, 2022
No significant endothelial apoptosis in the radiation-induced gastrointestinal syndrome
Bradley W Schuller1, Arlin B Rogers, Kathleen S Cormier
1Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Purpose:
This report addresses the incidence of vascular endothelial cell apoptosis in the mouse small intestine in relation to the radiation-induced gastrointestinal (GI) syndrome.
Methods And Materials:
Nonanesthetized mice received whole-body irradiation at doses above and below the threshold for death from the GI syndrome with 250 kVp X-rays, (137)Cs gamma rays, epithermal neutrons alone, or a unique approach for selective vascular irradiation using epithermal neutrons in combination with boronated liposomes that are restricted to the blood. Both terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining for apoptosis and dual-fluorescence staining for apoptosis and endothelial cells were carried out in jejunal cross-sections at 4 h postirradiation.
Results:
Most apoptotic cells were in the crypt epithelium. The number of TUNEL-positive nuclei per villus was low (1.62 +/- 0.03, mean +/- SEM) for all irradiation modalities and showed no dose-response as a function of blood vessel dose, even as the dose crossed the threshold for death from the GI syndrome. Dual-fluorescence staining for apoptosis and endothelial cells verified the TUNEL results and identified the apoptotic nuclei in the villi as CD45-positive leukocytes.
Conclusion:
These data do not support the hypothesis that vascular endothelial cell apoptosis is the cause of the GI syndrome.
