Acute heat stress responses of mice with sickle cell trait (1104.18)

It has been a long standing controversy about whether individuals with sickle cell trait (SCT) are vulnerable to injury or even sudden death during physical activity in hot climates. Experimental studies assessing susceptibility of SCT to heat stress are lacking. Our objective was to examine whether transgenic SCT mice had an altered thermoregulatory response to heat exposure. All SCT mice (n =16) and majority of age‐ and gender‐matched normal mice (29 of 45) completed two separate heat tests (2 hr each at 39.5 degree C) without severe hyperthermia (42.4 degree C). SCT mice had a significantly lower body weight than normal mice (n = 19) with similar peak core temperature (Tc). There was no difference in weight loss between SCT and normal mice during heat exposure. No significant correlations between peak Tc and body weight were found among SCT or normal mice. Compared to their normal counterparts, both non‐heat exposed (n = 9) and heat exposed SCT mice had significantly higher levels of heat shock protein 72 (HSP72) in various tissues, slightly lower hematocrit values, but similar plasma lactate dehydrogenase concentrations. No differences in plasma inflammatory and redox makers were found between SCT and normal mice following heat exposure. We conclude that SCT mice reveal neither thermoregulatory dysfunction nor increased oxidative/inflammatory stress when exposed to moderate heat. The physiological significance of increased tissue HSP72 remains to be determined. Grant Funding Source : Supported by The Office of Naval Research Grant N0001411MP2002 and USU Intramural Grant R091EH