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Vitamin E has previously been shown to provide radioprotection in animal models: increased survival after whole-body irradiation, diminished absorptive malfunction, and modest diminution in postirradiation hemolysis. The lumenal route for intestinal radioprotection has not been tested. MethodsRat mid-small bowel was surgically exteriorized and segmented by ties into compartments, each of which was filled with a test solution 30 minutes before 1 100 cGy of x-irradiation was administered. After the rats were killed 5 days later, the various segments were evaluated for surviving crypts, mucosal height, and goblet cell preservation. Lumenal agents included alphatocopherol phosphate and alpha-tocopherol acetate. In a separate study, dietary supplements of alpha-tocopherol were given for 10 days before irradiation, and the same irradiation sequence was carried out. ResultsSmall bowel crypt cell numbers, mucosal height, and goblet cell numbers were significantly protected from radiation effects by dietary alpha tocopherol pretreatment and by lumenal application of the vitamin. ConclusionsThese studies indicate that vitamin E can serve as a partial protectant against acute irradiation enteritis, whether given as chronic oral systemic pretreatment or as a brief topical application. 504Therapeutic irradiation regimens are designed to maximize tumoricidal effects while causing minimal damage to normal organs. Radiation to abdominal or pelvic malignancies unavoidably injures the intestine. Largely because of rapid cell turnover, the intestine is highly sensitive to radiation injury and is therefore the limiting factor in the permissible dosage for abdominal and pelvic irradiation. An early clinical consequence of intestinal

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