A Rat Model of Acute Heatstroke Mortality.

摘要

A total of 252 untrained, unacclimatized and unanesthetized laboratory rats weighing between 485-545 g were fasted and either run to exhaustion at 5, 20, 23, or 26 C or were restrained and heated at an ambient temperature of 41.5 C. The incidence of mortality associated with a wide range of work-induced hyperthermias was compared to the lethality of equivalent heat loads in the absence of physical effort. The severity of hyperthermia was calculated in degree-minutes above a baseline core temperature of 40.4 C. The LD 25's of run versus restrained rats were 16.8 and 30.1 degree minutes, respectively. Survivors had a faster cooling rate than fatalities, but run survivors had a slower cooling rate than heated survivors. Results indicate that: (1) both the incidence of mortality and the survival time can be predicted from the severity of core heating, (2) work-related factors contribute to an increased rate of heatstroke death at low thermal loads, and (3) retrospectively, both heat-sensitive and heat-resistant individuals were identified. (Author)