Radiation effect on the proliferating capillaries in rat transparent chambers.

The revascularization of the devascularized area in rat transparent chambers by the proliferating blood vessels was studied quantitatively on the changes of vascularity. On the vascularizing border, a hypervascular zone about 0-5 mm wide was formed. The border advanced constantly at 0-020 cm a day. Vascular density was fixed in the repaired area. The vascular length and repaired area increased on parabolic curves. The chambers were irradiated with single doses of 50, 100, 200, 400, 1000, 2000, and 4000 rad of 30Co gamma-rays, and the effects on the advance of the border were examined. With 200 rad and more, significant inhibition, greater with bigger doses, was seen in the advance of the borders. Regression of the borders also occurred. Irradiation with over 1000 rad destroyed the hypervascular zones.