Oxygen Changes in Tissues of Germfree and Conventional Mice after Inoculation of Bacterial Endotoxin.

Bacterial endotoxin when injected into mice prior to irradiation will give protection against whole body exposure to ionizing radiation. The greatest degree of protection is conferred when it is administered 24 hours before irradia tion.' Germfree mice withstand higher doses of x-rays than conventional mice2 and still higher doses when administered endotoxin before irradiation. 3 A reduction in oxygen tension (Po2) in tissues will reduce the tissue damage resulting from irradiation.' We undertook this study to see if the injection of bacterial endotoxin into mice had any effects on the Po2 of the animal's tissues.