Radiation effects in the small bowel of the diabetic mouse

Purpose : Irradiation of the small intestine in the mouse induces damaging structural alterations to the architecture of the enteric mucosa. There is growing interest in the possible relevance of underlying additional pathology when appreciating the total response of tissues to irradiation. The possibility that small intestinal mucosal abnormalities in the streptozotocin-induced diabetic mouse may exacerbate radiation-induced injury was tested by examining the combined effects of the two treatments. Materials and methods : Streptozotocin-diabetic and -non-diabetic mice were exposed to 10 Gy abdominal X-radiation. Profiles of mucosal epithelial cell populations were quantified and comparisons with corresponding groups of unirradiated mice made on the third day post-irradiation. Results : The histological appearances of the small intestinal mucosa were similar in both groups of irradiated mice, but the numbers of profiles of crypts and of columnar, goblet, Paneth and entero-endocrine cells were depressed in these groups when compared with values in corresponding groups of unirradiated mice. However, the expression of radiation damage in the diabetic mouse was less severe than in the non-diabetic mouse, particularly in the jejunum where the changes attendant on the onset of diabetes were most marked. Conclusion : These findings suggest that the response of mouse to radiation may be moderated by the presence of this type of pathophysiology. However, there is no evidence that the damage produced by streptozotocin-induced diabetes and radiation is additive.