Protective effect of vitamin A on acute radiation injury in the small intestine.

The objective of this study was to examine the influence of vitamin A on the development of early radiation-induced reactions in the rat small intestine. The early effects of intraoperative gamma-radiation on the small bowel utilizing the terminal ileum of Sprague-Dawley rats and the protective effect of supplemental vitamin A on acute radiation injury were investigated. Three groups were included in the study: group I (10 rats) was the surgical control group; group II (13 rats) underwent only intraoperative irradiation; and group III (10 rats) was the vitamin A plus irradiation group. Exteriorized terminal ileal segments of groups II and III were exposed to a single fraction of 20 Gy of intraoperative gamma-irradiation. On the seventh postoperative day, terminal ileal segments of all rats were resected and histopathologically evaluated for ulceration, enteritis cystica profunda, atypical epithelial regeneration, fibrosis, vascular sclerosis, and inflammatory process. Although none of the above findings were present in the surgical control group, group III rats experienced less severe effects than group II rats. The results suggest the early side effects of radiation may be prevented by vitamin A supplementation.