Effect of postradiation bleeding on proliferative activity of cells in small intestine crypts of rats.

The effect of postradiation bleeding on the dynamics of duodenal crypts' cells proliferation in rats was studied. The animals, females, three months old, weighing 170 or 180 g, were exposed to radiation of 800 R (115 R/min) and immediately after irradiation were bled by cardiac puncture to 50% of total blood volume. Proliferative activity of duodenal epithelium cells was monitored for a period of five days after irradiation. For control purposes normal, irradiated and only bled animals were used. The results demonstrated that although there are no significant differences in proliferative activity of duodenal epithelium cells in irradiated and bled animals and only irradiated animals, the postradiation reparative processes in irradiated and bled animals is considerably more stable. It is considered that bleeding itself by its hypoxic activity reduced the sensitivity of epithelium to the dose of radiation used. On the other hand, bleeding removed the damaging agents which appear after total body irradiation.