Screening And Functional Analysis Of Monitoring Markers For Heat Acclimatization Training Based On Metabonomics

Objective:A human heat acclimatization(HA)model is established to screen HA metabolic markers in saliva,and to explore the role of candidate markers in heat injury at the cellular and animal level,so as to provide new methods and ideas for rapid and accurate monitoring of HA training and experimental basis for heat injury protection.Methods:60 young men were selected as participants to carry out 12 d HA training.Using 3km running as heat stress test(HST),the effect of HA training was evaluated by monitoring the physiological and psychological load before and after HST on the 1st,5th,8th and 12 th day of HA training.Polar watch,infrared thermometer and stopwatch monitored the platform-phase heart rate,ear temperature and running time to calculate the training impulse(TRIMP)and physiological stress index(PSI),and collected thermal sensation(TS)and rating of perceived exertion(RPE)questionnaires.Saliva and plasma were collected on the 1st and 12 th day of HA training for metabonomic analysis.H9C2 cells were used as the research object.The cell viability was detected by CCK8 method,T-AOC was detected by biochemical kit and HSP70 was detected by Western Blot to evaluate the role of candidate markers in the model of cell heat injury(44℃,2 h).36 SD rats were randomly divided into control group(C),heat stress group(HS),pinocembrin control group(PB)and pinocembrin + heat stress group(PS),and were treated with pinocembrin for 42 days(30mg/kg/d).The body weight and rectal temperature of rats were monitored before and after heat stress(42℃,RH60%,30min/d,3d).The myocardium was taken with Western Blot and HE staining to detect the expression of HSP70 and morphological examination,and the serum was taken with Elisa and biochemical kit to detect the content of c Tn-I、LDH、Ang-Ⅱ、TNF-α、IL-6、IL-10、HSP70 and T-AOC、SOD、MDA.Results:1.TRIMP,PSI,RPE and TS decreased significantly after HA training,indicating that the body acquired HA.2.In saliva metabolomics,a total of 531 metabolites were identified,and 32 significantly different metabolites were screened(VIP>1,P < 0.05),enriching five metabolic pathways.Oxindole,3-phosphoserine,pinocembrin and phosphoenolpyruvate(FC>2,AUC > 0.7)were significantly relevant with the evaluation indicators of HA training.The level of plasma pinocembrin was significantly up-regulated after HA training.It is indicated that oxindole,3-phosphoserine,pinocembrin and phosphoenolpyruvate may be candidate markers for the evaluation of HA.3.Pinocembrin significantly increased the viability and T-AOC of H9C2 cells under HS,and significantly decreased the expression of HSP70 under heat stress(P < 0.001).It is suggested that pinocembrin may help to alleviate cell heat injury.4.Pinocembrin significantly decreased the rectal temperature and improved the myocardial morphology of SD rats after HS.The contents of c Tn-I,LDH,Ang-Ⅱ,MDA,TNF-α,IL-6 in serum and HSP70 in serum and myocardium were decreased,and the activities of T-AOC,SOD and IL-10 in serum were increased.Except for IL-6 and IL-10,there were significant differences(P < 0 05).It is suggested that PB may help to improve heat injury in animals.Conclusion:1.HA training helps to improve sports performance at high temperatures and reduce the risk of heat injury.2.Oxindole,3-phosphoserine,pinocembrin and phosphoenolpyruvate in saliva may be helpful to monitor HA training.3.Pinocembrin may reduce cellular and systemic heat stress response by regulating body temperature by cytokines,and enhance antioxidant capacity,thus alleviating heat injury.