Cooling Treament Has No Immediate Impact On Serum Epinephrine In Rats With Exertional Heat Stroke

PURPOSE: To explore the changes from serum epinephrine(EPI) and its regulatory effect on heat stress during cooling therapy in rats with exertional heat stroke. METHODS: Six groups of male SD rats were arranged to participate this study, including the room temperature control group(C, n = 8), the onset group of EHS (EHSO, n = 9), the room temperature group 1 after EHS(EHS1, n = 9), the Cold Water Immersion group 1 after EHS(CWI1,n = 8), the room temperature group 2 after EHS(EHS2, n = 9), and the Cold Water Immersion group 2 after EHS(CWI2, n = 8). In a hot and humid laboratory, we let the rats run on the treadmill until exhausted and raised their core temperature to about 42 °C, indicating the successful establishment of the EHS rat model. Cold water immersion(CWI) for 5 min at 19 °C was served as cooling therapy. ELISA method was used to determine serum EPI. The rat EPI kit was provided by Enzolife Corporation from the United States. The Mann-Whitney U test from Nonparametric test was adopted to analyze the data. RESULTS: At the moment of exertional heat stroke, serum EPI modulating thermogenesis was significantly up-modulated(EHSO vs. C) (EPI: 211.67 ± 32.34 vs. 151.16 ± 15.18 pg/ml, p < 0.01). After 5 minutes of cooling treatment, EPI did not show a significant change(CWI1 vs. EHSO or EHS1) (EPI: 230.25 ± 39.31 vs. 211.67 ± 32.34 or 231.07 ± 15.26 pg/ml, p > 0.05). After cooling treatment for 5 minutes and resting at room temperature for 60 minutes, EPI still did not show a significant change(CWI2 vs. EHSO or EHS2) (EPI: 248.83 ± 46.03 vs. 211.67 ± 32.34 or 228.03 ± 40.84 pg/ml, p > 0.05). CONCLUSION: At the onset of exertional heat stroke, there is a significant increase in serum epinephrine(excessive secretion), indicating a serious disruption of the body's thermal balance. It initiates a non-specific response to heat stress in response to the body's heat stress state. Cooling therapy has no direct impact on serum epinephrine, indicating that the effect of cooling therapy on regulating heat stress through the epinephrine defense mechanism is unclear or delayed. Supported by: The research of this thesis has sponsored by the key fund project of Scientific Research Compilation Plan Project in Anhui Province in 2022(Project Number: 2022AH051031). The research achievement has sponsored by the general fund project of Philosophy and Social Science Planning Project in Anhui Province in 2022(Project Number: AHSKY2022D184).