Injury and regeneration in rat small intestine cells after exposure to neutrons

The degree of damage to intestinal crypt epithelium and the process of its regeneration was studied after exposure to neutrons in rats. The aim of the study was an evaluation of the degree of impairment of proliferation of the stem cells in the intestinal crypts following exposure to one dose of 4 Gy, to two doses of 2 Gy each with an interval of 24 hours between them, and to one dose of 4 Gy administered together with a stimulator of leucopoiesis--Leukogen. The animals were administered 3H-thymidine and the per cent of its incorporation was determined. It was found that administration of the divided dose or of one total dose but together with the regeneration-stimulating agent prevented profound epithelial changes. The rate of return to normal incorporation was similar in the rats given the divided dose and in those receiving Leukogen.