Regulation Of Aldosterone On Water And Salt Metabolism During Cooling Therapy On Exertional Heat Stroke

Abstract

Corresponding Author: Bing Zhang. The pathophysiological mechanism of exertional heat stroke involves the imbalance of water and salt metabolism, but the effect of cooling therapy on serum aldosterone and the further regulation mechanism of water and salt metabolism is not clear. PURPOSE: To determine the changes of serum aldosterone and its regulation on water and salt metabolism in rats with exertional heat stroke under cooling therapy. METHODS: In our study, there are six groups of male SD rats, including the Normal environment Control group(NC n = 8), the Onset group of EHS(EHSO,n = 9), the Rest group 1 after EHS(EHSR n = 9), the Cooling group 1 after EHS(EHSC1,n = 8), the Rest group 2 after EHS(EHSR2 n = 9), the Cooling group 2 after EHS(EHSC2,n = 8). In hot and humid conditions(36 °C,75%RH), the rat model of exertional heat stroke was induced by exercising to exhaustion and raising their rectal temperature to about 42 °C. Cold water immersion for 5 min at 19 °C was used as rapid cooling therapy. Blood was harvested. Aldosterone in serum was measured by ELISA. Enzolife company in the United States provided ALD ELISA kit for rats. Mann-Whitney U test in nonparametric test was used for statistical analysis. RESULTS: With the onset of exertional heat stroke, serum ALD regulating water and salt metabolism was significantly up-regulated(EHSO vs. NC) (ALD: 122.51 ± 15.52 vs. 63.97 ± 16.28 pg/ml, p < 0.01). There was no significant change in serum ALD immediately after cooling therapy for 5 minutes(EHSC1 vs. EHSO or EHSR1) (ALD: 133.12 ± 17.62 vs. 122.51 ± 15.52 or 115.39 ± 13.90 pg/ml, p > 0.05). After cooling therapy for 5 minutes and resting for 60 minutes, serum ALD still had no significant change(EHSC2 vs. EHSO or EHSR2) (ALD: 131.49 ± 18.79 vs. 122.51 ± 15.52 or 115.70 ± 17.88 pg/ml, p > 0.05). CONCLUSIONS: When exertional heat stroke occurs, serum aldosterone increases significantly, which proves that the body has seriously unbalanced water and salt metabolism. Cooling therapy has no significant effect on serum aldosterone, which indicate that the regulation of cooling therapy on water and salt metabolism through aldosterone is not obvious or lagging. The research of this thesis has sponsored by the key fund project of philosophy and social science planning project of Anhui Province in 2020(Project Number: AHSKZ2020D25).