Reduced effect of irradiation on normal and malignant cells irradiated<i>in vivo</i>in mice pretreated with vitamin E

Abstract

The effect of vitamin E in reducing the permeability and increasing the resistance of capillaries might be expected to reduce the blood flow and hence the oxygenation of tissues. The question arises whether pretreatment of mice with vitamin E is associated with a reduced effect of irradiation on the cells of tissues. It was found that pre-treatment with vitamin E increased the LD50 (30) of mice from 565 ±38 rads (95 per cent confidence) to 630 ± 29 rads. Measurement of fractional survival for cells of murine squamous carcinoma irradiated in vivo in mice breathing air indicated that the percentage of anoxic cells in the tumours was raised from 13 per cent in untreated mice to about 35 per cent in mice pretreated with the vitamin.