The Effect of Body Temperature on the Sensitivity of the Haemopoietic Tissues of Mice to X-irradiation

The effect of x-irradiation on the haemopoietic tissues of mice while they are at body temperatures of 15°c is described.

Histological examination of the spleen and femoral bone-marrow revealed no differences between groups of animals irradiated at body temperatures of 15°c and those irradiated at normal body temperatures and then cooled to 15°c over the dose-range 0 to 950 r.

The total peripheral-leucocyte counts were compared with those obtained in previous experiments when animals were irradiated at body temperatures of 1°c and at normal body temperatures. Statistical analysis shows that on the evidence of leucocyte counts five days after irradiation, exposure of animals to x-rays while they are at body temperatures of 15°c affords slight protection to the haemopoietic tissues, which is much less than the protection provided at body temperatures of 1°c when the animals are severely hypoxic. Cooling to 15°c after irradiation affords no detected radioprotection.