Experimental Frostbite: Oxygen Consumption and Anaerobic Glycolysis of Rat Tissues After Freezing and Cooling in Vitro

¹ From the Department of Physiology, School of Medicine, Stanford University, Stanford, California

Rates of oxygen consumption and anaerobic glycolysis in rat tissues were determined at 37.5°C after these tissues had been frozen or cooled in vitro; these rates were compared with those of uncooled control samples from the same animals. Cooling skin without freezing for as long as 22 hr. at –0.4°C did not reduce the Qo₂ determined upon rewarming. Supercooling skin (without freezing) did not impair its capacity to consume oxygen upon rewarming but freezing at the same temperature did result in such impairment. The Qo₂ of skin, skeletal muscle, nerve, cerebral cortex and liver which had been frozen at temperatures between –5°C and –25°C was always lower than that of unfrozen controls. The rate of anaerobic glycolysis of skin, muscle, liver and brain was reduced after freezing. In general, the impairment of metabolism increased with decrease in temperature or increase in duration of the frozen state. The metabolism of skin was much more resistant to freezing than that of other tissues studied. No impairment of Qo₂ of sucrose liver homogenates was produced by freezing for 1 hr. at –25°C and only about 20% reduction of Qo₂ of water homogenates of liver or brain was produced by freezing for up to 5 hr. at that temperature. When tissue slices were frozen, and the Qo₂ subsequently determined, in fortified media resembling those used for the homogenates, the impairment of Qo₂ resulting from freezing was far less than in Ringer's solution. These results are discussed in relation to the tissue damage produced by frostbite.