ABSTRACT
Objective To observe the pathophysiological changes of heat exposed (41.0-41.5 ℃) rats, including the change of rectal temperature (core temperature, Tco), mean arterial pressure (MAP) , heart rate (HR) and the protein expression characteristic of Hsp70 mRNA in the brain, heart and lung. Methods After Tco was measured, Wistar rats were exposed to the heat environment (a chamber, 41.0-41.5 ℃) till to death. Tco, MAP and HR were monitored continuously by the temperature measurement instrument and remote sensing pressure-monitoring system. The expressions of Hsp70 mRNA and protein in the brain, heart and lung were determined by RT-PCR and Western blot. Results Tco, MAP and HR increased continuously when the rats were exposed to the heat environment. After MAP and HR started decreasing from peak value, heatstroke was induced. The time to induce heatstroke in the heat environment (41.0-41.5 ℃) was (35?2) min. After heatstroke MAP quickly decreased and HR was not normal. At last, Tco increased to the peak (45.0 ℃) and the animal was dead. The expressions of Hsp70 mRNA and protein in the brain and heart were low and the expression in the lung was high while they were obviously induced by heat treatment. The level of Hsp70 mRNA in the brain, heart and lung was approximately 5.19, 6.88 and 1.80 times of that in the normal control group (P