The arrest of intestinal epithelial 'turnover' by the use of x-irradiation

Mitotic activity and hence cell turnover has been abolished by x-irradiation with 1,000 r. in segments of the rat's gut. The whole stomach, the ascending colon, and 5 cm. of jejunum and ileum were irradiated and the changes observed histologically up to three days. Cessation of cell turnover in the small intestine is followed by cell death and desquamation within 24 hours, leading to denudation of the epithelium and collapse of villous structure. The pylorus and colon showed similar but less marked changes. In contrast the fundus and body of the stomach were unaffected by the absence of mitosis over a period of three days. It is concluded that cell turnover is, in part, necessary to maintain the mucosal structure, particularly the villous pattern in the small intestine.