| Background:Element is the basic constituent unit of any substance in nature,including organism,which plays a vital role in all life activities of the organism.The absorption,transport,distribution and excretion of trace elements in the body are closely connected with the health status of the body.In recent years,professor Guo Jiao first put forward the innovative theory of“Glucolipid Metabolic Disorders”(GLMD),suggesting that GLMD is characterized by glycolic and lipid metabolism disorder and involves five core pathological mechanisms including neuroendocrine disorder,insulin resistance,oxidative stress,inflammation and intestinal flora disorder,but the dynamic change characteristics of GLMD microelement spectrum are still unclear.Therefore,we propose a practical strategy for the study of t trace element profiling,which is to combine the"omics"strategy with"trace element analysis"to conduct an overall analysis of the trace element level of the body.At the same time,combined with multiple statistical thoughts,the representative disease of glucose and lipid metabolism disease-hyperlipidemia is characterized and potential bio-element markers are found,and the role of key trace elements in regulating lipid metabolism disorders is further analyzed.Objective:To establish qualitative and quantitative analysis method for the study of trace element profiling,construct the trace element spectrum of hyperlipidemia.Based on the trace element characteristic spectrum to characterize hyperlipidemia,we search for potential bio-element markers and conduct in-depth research on the key trace element regulating lipid metabolism mechanism.Methods:1.Optimization and investigation of trace element profiling methodologyThe trace element profiling research method of serum,feces and hair samples were established,and the sample pretreatment method,instrument tuning status,and data acquisition parameters was optimized.Inductively Coupled Plasma Mass Spectrometer(ICP-MS)was used to detect trace element standards and biological samples.Regarding the evaluation of the accuracy of the test results of this method,in the aspect of semi-quantitative analysis,the precision,repeatability,and stability tests was investigated.In the aspect of full quantitative analysis,the linear coefficient,detection limit,limit of quantification,precision,repeatability,stability,and sample recovery of the standard curve were examined.2.Application of trace element profiling in disorders of glucose and lipid metabolismAn animal model of hyperlipidemia in SD rats was established by high-fat emulsion gavage.The animal model of hyperlipidemia was evaluated by four blood lipid,blood glucose and body weight indicators.The established ICP-MS trace element analysis method was used to qualitatively and quantitatively analyze the trace elements in serum,feces and hair of hyperlipidemia rats,and a trace element spectrum of animal models of hyperlipidemia was constructed.The pattern recognition analysis method was combined with multivariate statistical analysis to find potential trace element markers in serum,feces and hair of animal models with hyperlipidemia.The receiver operating characteristic curve(ROC curve)was constructed,and the accuracy of predicting hyperlipidemia with potential element markers was investigated by using the area under the curve(AUC).3.Regulation lipid metabolic disorder of trace element the key mechanism researchThe symbiotic network map between trace elements and intestinal flora was established,and the trace elements closely related to colonic flora were analyzed as the primary research objective.Taking mouse embryonic fibroblasts(3T3-L1 pre-adipocytes)as the research object,the effects of specific microelement intervention on the activity of 3T3-L1pre-adipocytes were determined by tetramethylazolium salt microscope reaction colorimetry(MTT).To induce differentiation of preadipocytes into adiposity,the effects of the intervention of specific trace elements on the differentiation of preadipocytes were observed,and the role of trace elements in the regulation of lipid metabolism was further analyzed and the mechanism was explored.Result:1.Optimization and investigation of trace element profiling methodologyThe results of semi-quantitative methodological investigations showed that among the 75 elements detected,the element precision RSD of more than 88.00%was less than 20%,the repeatability RSD of more than 85.33%elements was less than 20%,and the element stability RSD was more than 20%.The results of the full quantitative methodological investigation showed that the standard curve R~2 of the four trace elements of Cr,Mn,Cu,and Pb were all greater than 0.95,and the linear relationship was good,meeting the quantitative requirements.The RSD values obtained from the precision,repeatability,and stability studies were all less than 10%.The overall results show that the instrument has good precision.The experimental method can be repeated,and the sample to be tested is stable within 24 hours.It can be used for the quantitative detection of trace elements in serum,feces and hair samples of hyperlipidemia model animals.2.Application of trace element profiling in hyperlipidemia model ratsA hyperlipidemia rat model was established by high-fat emulsion gavage.Blood glucose and lipid indexes were abnormal,and the expression of trace elements was disordered.The serum trace element expression profile can be effectively discriminate hyperlipidemia model rats from healthy control rats,and a total of 75 trace elements can be constructed for the glucose and lipid metabolism disorder trace element profile.Through principal component analysis and partial least squares discriminant analysis,seven trace elements with significant differences were found,namely:Na,Mg,Al,Cr,Mn,、Cu,Pb;The disease prediction ability of each element was analyzed by ROC curve,and the potential element markers of hyperlipidemia were finally determined as Na,Mg,Cr,Cu,Pb.3.Study on the mechanism of regulating glucose and lipid metabolism disorder of key trace elementAccording to trace element-intestinal flora symbiotic network map,the correlation degree between trace element Cr and intestinal flora in feces of hyperlipidemia model rats was high,and the cell experiment showed that Cr intervention would affect the proliferation and differentiation of 3T3-L1 pre-adipocytes.Conclusion:In this study,trace element profiling was successfully established in different biological samples(serum,feces,hair)and applied to the study of hyperlipidemia.ICP-MS was utilized to detect the expression of trace elements in hyperlipidemia model and healthy control rats,and it was found that the expression of trace elements in hyperlipidemia model rats was abnormal,and the trace element expression profile could effectively characterize the characteristics of hyperlipidemia.Multivariate statistical analysis showed that the contents of Na,Mg,Al,Cr,Mn,Cu and Pb were significantly changed in the hyperlipidemia model group and the healthy control group.The contents of Cr were significantly decreased in the hyperlipidemia model group,while the contents of Na,Mg,Al,Mn,Cu and Pb were significantly increased.Through ROC curve analysis,it was found that Na,Al,Mn,Cu and Pb had strong prediction ability for hyperlipidemia,which could be used as potential elemental markers for hyperlipidemia,and was expected to be used for clinical diagnosis and post-healing observation of hyperlipidemia.Trace elements were used as environmental factors to establish a symbiotic network map of intestinal flora and trace elements,and it was found that Cr was most closely related to intestinal flora.Preadipocyte assay of 3T3-L1 showed that Cr interfered with the proliferation and differentiation of preadipocytes.It is concluded that trace elements play an important role in lipid metabolism,and Cr may be involved in the regulation of lipid metabolism by affecting the bioactivity of intestinal flora and/or affecting related enzymes,hormones or cytokines in the signal pathway related to pre-adipocyte differentiation. |
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