Intestinal Radioprotection by Vitamin E (alpha-tocopherol)

Objectives: The major objective of this study was to test vitamin E as a potential radioprotectant for the small bowel of the rat.

Summary Background Data: 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.

Methods: Rat mid-small bowel was surgically exteriorized and segmented by ties into compartments, each of which was filled with a test solution 30 minutes before 1100 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 alpha-tocopherol 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.

Results: Small 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.

Conclusions: These 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.