Radioprotectant effects of atropine on small intestinal villous shape.

Previous work has shown that irradiation produces changes in small intestinal villous shape, which can be quantified using a villous scoring system applied to scanning electron micrographs. It has already been shown that reserpine, which, like irradiation, increases gastrointestinal motility, produces a similar type of villous collapse, thereby supporting the theory that this form of injury may not be due entirely to changes in the cryptal epithelial compartment, as has been assumed previously. Atropine, chosen for its ability to decrease gut motility, produces a different form of villous shape change. The aim of the current work was to investigate the ability of atropine to decrease the villous damage caused by irradiation and thereby improve the likely absorptive capacity of the small intestine. The current experiments used crypt counting, qualitative light microscopy and villous scoring techniques. Groups of unirradiated mice examined included baseline controls and those treated with atropine, sham irradiation and a combination of these two schedules. Two irradiated groups were studied, one with and one without atropine treatment. The results show that atropine given with irradiation reduces the extent of the damage to villous shape, implying that the total effect on the neuromuscular tissues is less destructive after the combined treatment. It is also of interest that atropine appears to have an additional radioprotectant effect on the radiation induced crypt depletion, implying that neuromuscular behaviour may influence this compartment, hitherto considered as dependent on epithelial proliferative capacity.