Lipid Metabolomics Analysis In Lung Tissue Of BALB/c Mice Model With Asthma Induced By Ovalbumin

Background and objectsBronchial asthma is a disease caused by the interaction of multiple factors such as genetics,epigenetics and occupational environmental exposure,which is characterized by chronic inflammation with complex pathogenesis.There are about 300 million asthma patients in the world,and more than 250,000 people die of asthma each year,and there are about 30 million asthma patients in China,this disease is seriously affect human health.At present,the morbidity and mortality of asthma are still increased year by year,but the pathogenesis of asthma is still not completely cleared.Therefore,it is urgent to in-depth research and find new effective targets for diagnosis or treatment of asthma.Lipids are important components of biofilms and have important biological functions,such as participate in important biological processes included cell electron transmission,signal transduction and cell growth and migration,et all.In modern society,unhealthy lifestyle and long-term overnutrition often lead to severe lipid metabolism disorder leading to a variety of chronic diseases.Recent studies have found that lipid metabolism is involved in the pathogenesis of asthma.The emerging metabolomics is a comprehensive analysis of the species and concentration of endogenous small molecule metabolites(<1 kDa)in the body.Lipidomics is an important branch of metabolomics.It is a new subject that can systematically analyze lipids in vivo,compare the changes of lipid metabolism spectrum under different physiological states,identify and screen the key lipid biomarkers in the regulation of metabolism,to reveal the mechanism of lipids in various life activities.As the most sensitive metabolomics technique,mass spectrometry is the core technology of lipidomics research and has been widely used to identify new biomarkers and understand the molecular mechanisms of diseases.At present,there are relatively few studies on the lipid histology of asthma.We will analyze the change of metabolites in lung tissue of BALB/c mice model with allergic asthma induced by Ovalbumin(OVA)by the lipidomics method which based on liquid chromatography-mass spectrometry(LC-MS),to seek the potential lipid biomarkers for the diagnosis of asthma,provide prophase research foundation for the next step research of how the lipid metabolism involved in the pathogenesis of asthma mechanisms.MethodsChoosed 16 BALB/c mice and randomly divided into asthma group(Ath)and control group(Ctr),building the asthma mice model induced by OVA,assessing the airway hyperresponsiveness in mice by methacholine(Mch)challenge test,detecting the cell factors in the BALF of mice by enzyme-linked immunosorbent assay(ELISA)method to,detecting the content of Malondialdehyde(MDA)in lung tissue of mice by the chromogenic reaction of MDA and Thiobarbituric acid(TBA)method,observing the pathological changes of lung tissue of mice by H&E staining and Masson staining.We will analyze the lung tissues of mice by lipidomics method which based on LC-MS.Simca-p14.1 software is used for data processing and analysis,including principal component analysis(PCA),partial least squares-discriminant analysis(PLS-DA),orthogonal partial least squares discriminant analysis(OPLS-DA),student’s T-test,and multiple of variation analysis.Drawing volcano plot and hierarchical clustering analysis plot with R language software(v3.1.3).We screen the significant different lipids by t-test(P<0.05)and multiple change value(|log2(fold chage)| > 0.585).Using SPSS 21.0 statistical software to compare the Penh value,total number of cells,eosinophilic grain number and the concentration of IL-4,IL-5,IL-13 and thymic stromal lymphopoietin(TSLP)in BALF between two groups of mice,and drawing the Receiver Operating Characteristic(ROC)curve of significantly different lipids,and comparing the area under the ROC curve(AUC).Results 1.Penh values of mice in the asthma group and the control group increased with the increase of Mch concentration.When the concentration of Mch was 12.5,25 and 50mg/ml,the Penh value of mice in the asthma group was significantly higher than those in the control group(all P < 0.05).2.The total number of cells,number of eosinophil granulocyte and the concentrations of IL-4,IL-5,IL-13 and TSLP in BALF of mice in the asthma group were significantly higher than those in the control group(all P < 0.05).3.H&E staining of lung tissue of mice in the asthma group showed obvious thickening of airway wall,stenosis of lumen and infiltration of a large number of inflammatory cells,and Masson staining showed a large amount of collagen deposition in airway and around blood vessels.4.MDA content in lung tissues of mice in the asthma group was significantly higher than those in the control group(P < 0.05).5.About 434 lipids were detected in the lung tissues of mice,included 55 kinds of sphingolipids,4 kinds of sterols,253 kinds of glycerophospholipids and 122 kinds of glycerides,among those 30 kinds of lipids were significantly different in the asthma group and the control group(all P < 0.05).There were 7 differential lipids which AUC>0.9 included the SM(d18:2/24:1),TG(10:0/18:2/18:2),TG(16:1/16:1/17:1),TG(18:0/18:0/22:6),TG(18:1/18:2/23:5)and TG(18:1/18:2/23:1).Conclusions 1.The lipid metabolism profiles of mice in the asthma group are different from those in the control group,which are mainly manifested by the differences in three metabolic pathways: glycerophospholipids,glycerides and sphingomyelins.2.7 lipid metabolites may be the lipid biomarkers for the diagnosis of asthma,included the SM(d18:2/24:1),TG(10:0/18:2/18:2),TG(16:1/16:1/17:1),TG(18:0/18:0/22:6),TG(18:1/18:2/23:5)and TG(18:1/18:2/23:1).