Body temperature regulation in mice resuscitated from deep hypothermia

¹ Departments of Physiology and Rehabilitation Medicine, Albert Einstein College of Medicine, New York City and Department of Pathology, Tufts-New England Medical Center, Boston, Massachusetts

Body temperature regulation was studied in mice following resuscitation from deep hypothermia induced by means of the closed-vessel cooling technique. Forty per cent of the animals cooled to and maintained at a colonic temperature below 5 C (lowest mean colonic temperature = 1.5 C) failed to demonstrate body temperature regulation when exposed to 2 C air for 30 min at 7-day intervals for a period of 70 days following resuscitation. Mice cooled to 5 C and immediately resuscitated showed a temporary loss in body temperature regulation. Loss of body temperature control did not occur in any of the control groups. Histological examination of midbrain sections taken from animals in each group showed pathological changes. There was no correlation between body temperature regulation and brain pathology. Mice resuscitated from sustained deep hypothermia showed impaired body temperature regulation upon heat exposure (39 C for 60 min) 7 days later. These data indicate that mice subjected to prolonged deep hypothermia induced by means of the closed-vessel cooling technique show poikilothermic responses following recovery. Furthermore, permanent loss of body temperature regulation upon cold exposure may result from this procedure.

Note:
With the Technical Assistance of D. Pennec and D. Glaubinger

Submitted on February 21, 1963