The Biochemical Mechanism Of Antihyperlipidemia Rats Of Poria Cocos And Its Surface Layer By UPLC-HDMS-based Metabolomics

Hyperlipidemia(HLP)has become one of the major risk factors with high morbidity.Poria cocos(Schw.)Wolf(PC)is the traditional Chinese medicine and is clinically used to treat edema and insomnia.The surface layer of Poria cocos(SLPC)has similar effects to PC but exhibits stronger effects against edema than PC.It has been demonstrated that PC and SLPC are commonly used to treat HLP,but the mechanism is remain unclear.As one of the emerging system biology technologies,metabolomics is mainly used for new biomarkers discovery,disease diagnosis and prognosis,and the evaluation of drug activity and toxicity.Lipidomics is an important branch of metabolomics which has advantages in elucidating the relationship between the occurrence of diseases or the mechanisms of drug action and lipid metabolism.At present,metabolomics and lipidomics have been widely investigated and implicated in the intervention effects of HLP.Objective:We identify numerous endogenous lipid metabolites and metabolic pathways of PC and SLPC against HLP by using ultra performance liquid chromatography-high definition mass spectrometry(UPLC-HDMS)method,and further investigate intervention effects of PC and SLPC on these biomarkers,which will elucidate the biochemical mechanisms of PC and SLPC for treating HLP.Methods:Male Sprague-Dawley rats weighing 200-220 g(n=8)were randomly divided into control group,model group,PC-intervented group.The control group was fed with regular diet,while the model group and PC-intervented group were fed with high-fat diet for successive 6 weeks.Subsequently,the PC-intervented group was orally administered ethanol extract of PC(250 mg/kg/d).The control group and model group were only administered with water by oral gavage for 6 weeks.Blood samples were collected for biochemical parametars and plasma lipidomics analysis.Urine metabolomics lipidomics study of PC against HLP and plasma lipidomics study of SLPC against HLP were applied in the same method.Results:1.The results of plasma lipidomics study of PC for the intervention of HLP rats.The levels of total cholesterol,triglyceride,and low density lipoprotein-cholesterol in the model group were significantly increased.Intervention with PC significantly reduced the increased levels of these indicators and ameliorated dyslipidemia.Based on plasma lipidomics,a total of 22 lipid metabolites were identified in these four groups.Among them,14 lipid metabolites including palmitic acid,hexadecenoic acid,hexanoylcarnitine,tetracosahexaenoic acid,cervonoyl ethanolamide,3-hydroxytetradecanoic acid,5,6-DHET,cholic acid,cholesterol ester(18:2),hydroxytestosterone,19-hydroxydeoxycorticosterone,tyromycic acid,lyso PC(16:0)and sphingosine 1-phosphate were selected and identified as plasma lipid biomarkers of PC against HLP.Further studies revealed that these lipid biomarkers are associated with sphingolipid metabolism,glycerophospholipid metabolism,primary bile acid biosynthesis,GPI-anchor biosynthesis,mitochondrial fatty acid elongation,biosynthesis of unsaturated fatty acid,fatty acid metabolism and biosynthesis,arachidonic acid metabolism,steroid hormone biosynthesis and steroid biosynthesis 11 metabolic pathways.2.The results of urinary metabolomics study of PC for the intervention of HLP rats.Based on UPLC-HDMS metabolomics,a total of 18 metabolites were identified in the urine of the HLP model group which showed significantly differences.Finally,three metabolites including arginine,aminoadipic and citric acid were identified as the anti-hyperlipidemic biomarkers of PC.Further studies revealed that HLP are associated with the disorders of amino acid metabolism,tricarboxylic acid cycle,fatty acid metabolism and nucleic acid metabolism pathways.The intervention of ethanol extract of PC ameliorated the dyslipidemia and abnormal metabolic pathways.3.The results of plasma lipidomics study of SLPC for the intervention of HLP rats.The levels of total cholesterol,triglyceride and low density lipoprotein-cholesterol in the HLP model group were significantly increased and intervention with ethanol extract of SLPC significantly reduced the increased levels of these indicators and ameliorated dyslipidemia.Based on UPLC-HDMS metabolomics,a total of 6 lipid metabolites including palmitic acid,phytosphingosine,dodecanoic acid,L-palmitoylcarnitine,oleoylcarnitine and linoleyl carnitine were identified as plasma biomarkers of SLPC against HLP.These biomarkers are associated with fatty acid metabolism,fatty acid biosynthesis,sphingolipid metabolism,fatty acid elongation in mitochondria and unsaturated fatty acids biosynthesis metabolic pathways.Conclusion:This study illuminated the intervention of PC and SLPC could ameliorate the dyslipidemia and abnormal metabolites in high-fat diet-induced HLP rats.The pathogenesis of HLP is mainly associated with disorders of metabolic pathways including fatty acid metabolism,sphingolipid metabolism,mitochondrial fatty acid elongation,amino acid metabolism,and tricarboxylic acid cycle.The intervention with ethonol extract of PC and SLPC significantly ameliorated the abnormality of these metabolic pathways which will demonstrate the effects and mechanisms of PC and SLPC agains HLP.