Physiological Cycle And Salivary Metabolites Of Female Soldiers In Military Training In Hot Regions

Background:High temperature is one of the main features of the hot area environment in China,and it is an unavoidable potential threat for special populations that need to work in high temperature environments for long periods of time,which can not only reduce operational capacity,but also affect health.High-temperature environments have a clear effect of causing disruption of the kinetic cycle in females,but the mechanism is unknown and biomarkers of the effects of the physiological cycle have not been clarified.Therefore,the study of the characteristics of physiological cycle changes in female soldiers due to high temperature environment and related mechanisms is significant for the maintenance of physiological cycle health and targeted protection of female in high temperature environment.Saliva,which can be collected noninvasively,easily,safely,and economically,is an information-rich biological fluid,and metabolites in blood can enter saliva via extracellular,intracellular,or paracellular pathways.Therefore,saliva metabolites may provide a window into other parts of the body for early detection and screening of human diseases.In this study,we analyzed the physiological cycle characteristics of female soldiers in high-temperature environments and used non-targeted salivary metabolomics techniques,combined with targeted neurotransmitter metabolomics studies,to screen metabolic markers and elucidate the regulatory mechanisms of high-temperature environments affecting the physiological cycle of military training female soldiers.It provides a scientific basis for the construction of a non-invasive and convenient way to monitor physiological cycle disorders,and lays a scientific foundation for safeguarding the reproductive health of female soldiers in high-temperature environments.Methods:In this study,125 female soldiers of the same arm were selected.They were21.95±2.56 years old and had a BMI of 20.83±2.6 kg/m².They had no smoking or drinking habits,it was basically the same including their working hours,exercise intensity,and diet.Among them,45 female soldiers in the hot areas of China are in the high temperature group(the annual average temperature is 20?28?),and 80female soldiers in the control region are as the normal temperature control group(the annual average temperature is 0?10?).The study was carried out in summer,and the average temperature of the high temperature group was 28?38?,and the average temperature of the control group was 15?25?.A cross-sectional questionnaire survey was used to investigate the rate of physiological cycle disorders,characteristics of physiological cycle disorders,PMS,SCL-90 mental status and factors contributing to physiological cycle disorders in different regions,and to conduct comparative analysis.ELISA kits were used to detect six sex hormones including FSH,LH,E₂,P,T,PRL,to evaluate the impact of high temperature environment on female sex hormones and the characteristics of changes.Non-targeted metabolomics was used to analyze the saliva of the two groups of female soldiers,to screen different salivary metabolites.Cluster analysis and KEGG pathway analysis enrichment were performed to look for potential markers of female soldiers'menstrual cycle disorder caused by high temperature,and their possible participation of regulatory pathways.Targeted metabolomics was used to detect the relative content of 10 neurotransmitters in the serum of the two groups of female soldiers,including Glutamine,r-Amino-butyric acid,Normetanephrine,Dopamine,5-HIAA,Acetylcholine,DOPA,Serotonin,3-Methoxytyramine and Histamine,to evaluate the characteristics of neurotransmitter changes in female soldiers caused by high temperature environment,and provide better evidence for saliva metabolomics research.Results:(1)The menstrual cycle disorder rate of military training female soldiers under high temperature environment reached 75.56%,which was significantly higher than 57.5%of the female soldiers in the control group(P<0.05);and the female soldiers in high temperature environment showed obvious menorrhagia menstrual cycle characteristics.(2)No significant difference of the premenstrual symptoms between the two groups of female soldiers was shown(P>0.05).(3)Some influence factors of female soldiers are at increased risk of menstrual cycle disorders,including anxiety(OR(95%CI)=6.550(1.360-31.545),P=0.019),high pressure(OR(95%CI)=5.647(1.123-28.384),P=0.036),poor sleep quality(OR(95%CI)=7.303(1.433-37.226),P=0.017),subjective temperature discomfort(OR(95%CI)=7.375(1.110-48.992),P=0.039)(4)The mental status of the two groups of female soldiers was analyzed and compared using the SCL-90 mental self-measurement table.The results showed that the following subscales were significantly higher the high temperature group than in the control(P<0.05).The total score of the SCL-90 scale in the high temperature group was 129.44±33.87 points,and the score of the control group was 113.58±24.19 points;Somatization,anxiety,the depression and paranoid mind subscale score were 1.44±0.56,1.32±0.47,1.50±0.66 and 1.32±0.47 respectively in high temperature group,while 1.22±0.42,1.13±0.37,1.19±0.43 and 1.10±0.35respectively in control group;it is significant higher in the high temperature group than the control group(P<0.05),and there is no significant difference in the other subscales.(5)The concentration of PRL in the sex hormone determination of the two groups of female soldiers was 23.34±7.52 ng/ml in the high temperature group,significantly higher than the control group which was 16.83±4.57 ng/ml(P<0.05).The contents of FSH,T,E₂,LH,and P were not significantly different between the two groups of female soldiers(P>0.05).(6)A total of 64 significantly different metabolites were identified(P<0.05),of which 34 salivary metabolites were up-regulated and 30 salivary metabolites were expressed Down.Furthermore,it is found that the difference metabolites can mainly be enriched in fructose and mannose metabolism,galactose metabolism,pentose phosphate pathway,amino sugars and nucleotides,carbohydrate metabolism,ascorbic acid and aldehyde acid metabolism,ABC transporter,protein digestion and absorption,pyrimidine metabolism and other pathways with KEGG pathway analysis.Among them,N-Acetylneuraminic acid,Myo-Inositol,Tyramine,etc.change significantly,and may be candidate markers.(7)Using targeted metabolomics to analyze the serum neurotransmitters of the two groups of female soldiers,it was found that the levels of Histamine and Glutamine increased in high temperature environments,and the Fold Change were 2.077 and1.366,respectively.The relative content of 5-HIAA decreased,and the Fold Change was 0.701(P<0.05).Conclusion:(1)High temperature environment can increase the rate of women's menstrual cycle disorder,and may increase women's menstrual volume;(2)Menstrual cycle disorder has closed relations with frequent anxiety,high pressure,poor sleep quality,uncomfortable temperature in the resident environment,etc.(3)In a high temperature environment,women are more likely to produce negative emotions such as anxiety and depression;(4)Salivary metabolites such as N-Acetylneuraminic acid,Myo-Inositol,and Tyramine may be candidate markers for menstrual cycle disorders by participating in endocrine regulation,influencing cell membrane production,participating in immunomodulatory responses,and participating in mood regulation in high temperature environments.