Metabonomics Study Of White Adipose Tissue And Brown Adipose Tissue In Tree Shrews (Tupaia Belangeri) During Cold Acclimation

In order to maintain body temperature stability in cold conditions,mammals usually activate complex multi-organ metabolic responses to increase thermogenesis,in which adipose tissue plays an important role in regulating the body temperature of animals.White adipose tissue(WAT)mainly plays key role on energy storage,and brown adipose tissue(BAT)is the main part of nonshivering thermogenesis(NST),which plays an important role in resisting low temperature environment in small mammals.In the present study,liquid chromatograph-mass spectrometer(LC-MS)was used to perform untargeted metabolomics analysis of WAT and BAT in Tupaia belangeri during cold acclimation(5?),using principal components analysis(PCA),hierarchical clustering analysis,metabolic pathway analysis etc.to compare the differences in biochemical composition between WAT and BAT,clarifying how the two adipose tissues respond to the low temperature environment in terms of metabolomics under cold stress,which elucidate the metabolic process and energy homeostasis regulation mechanism of T.belangeri,and to deeply understand the survival of small mammals in the eastern world in response to environmental changes adaptation mechanism and evolutionary significance.This thesis consists of two parts:(1)Metabonomics study of WAT in T.belangeri during cold acclimationLC-MS was used to perform untargeted metabolomics analysis of WAT of T.belangeri during cold acclimation(5?).Statistical analysis and hierarchical clustering analysis showed that there were 34 differential metabolites,of which 26 were up-regulated and 8 were down-regulated.Differential metabolite pathway analysis showed that there are 6 metabolic pathway metabolites in the WAT metabolic pathway of T.belangeri under cold acclimation.It was a very important connection position in thermogenesis,of which only the number of tissue polar differential metabolites in tricarboxylic acid cycle(TCA cycle)pathway were significant for the entire pathway coverage.Therefore,increasing the concentration of the intermediate products of TCA(citric acid,cis aconitic acid),pyruvic acid,and phosphoenolpyruvic acid(PEP)to increase the thermogenic capacity of T.belangeri to cope with cold stress in WAT.(2)Metabonomics study of BAT in T.belangeri during cold acclimationLC-MS was used to perform untargeted metabolomics analysis of BAT of T.belangeri during cold acclimation(5?).Statistical analysis and hierarchical clustering analysis showed that there are 59 differential metabolites,of which 45 were up-regulated and 14 were down-regulated.Differential metabolite pathway analysis shows that there were 15 metabolic pathway metabolites in the BAT metabolic pathway of T.belangeri under cold exposure.It was very important connection position in heat generation,of which the number of tissue polarity differential metabolites in TCA cycle,glyoxylate and dicarboxylate metabolism pathways were significant for the entire pathway coverage.Therefore,increasing the metabolites in TCA cycle,glyoxylate and dicarboxylate metabolism pathways by citric acid,cis aconitic acid,L-malic acid,pyruvic acid,phosphoenolpyruvic acid(PEP),and glyceric acid in BAT,which to increase the thermogenic capacity of T.belangeri in response to cold stress.Comparing the differential metabolites between WAT and BAT,the statistics of differential metabolites and hierarchical clustering analysis showed that there were 20 different metabolites in T.belangeri during cold acclimation.There are 11 kinds of metabolite concentrations that are up-regulated,all of which are amino acid and nucleotide metabolites in BAT,and 9 kinds that are down-regulated in WAT.Comparing the influence factor map of metabolic pathway and differential metabolite pathway analysis in T.Belangeri under cold acclimation,there were more differential metabolic pathways in BAT of T.belangeri during cold acclimation than that of in WAT.In conclusion,WAT and BAT had significant differences in various metabolic pathways such as sugar metabolism,amino acid metabolism,lipid metabolism,and nucleotide metabolism,and these differences were closely related to the different biological roles of the two tissues.T.belangeri enhanced the thermogenic activity by adjusting the concentration of intermediate products of various metabolic pathways in WAT and BAT to cope with cold stress.Moreover,the changes of BAT during cold acclimation were greater than that of in WAT.Compared to WAT,BAT responds to cold stress by adjusting the concentration of nucleotide metabolites.