Effect Of Polyunsaturated Fatty Acids And Mode Of Mechanism On Browning Process Of 3T3-L1 Adipocytes

ObjectiveNew effective treatment approaches are needed to cope with the rapid growing epidemic of obesity and metabolic diseases.Scientists have recently focused on brown adipose tissues in humans because they could promote energy metabolism and improve glucose and lipid metabolism.The n-3 and n-6 polyunsaturated fatty acids(PUFAs)have been proved to improve obesity through modulating the differentiation and function of adipocytes.The aim of this study is to investigate the browning effect of n-3(docosahexaenoic acid,DHA;eicosapentaenoic acid,EPA)and n-6 PUFAs(arachidonic acid,AA)and mode of mechanism on 3T3-L1 adipocytes at different stages of differentiation through analysis of levels of glucose,lipid,browning marker gene expression and mitochondrial biogenesis.Methods3T3-L1 adipocytes at different stages of differentiation were treated with DHA,EPA and AA at 10 μM and 100 μM,respectively.The levels of glucose consumption and triglyceride were measured by commericial kits.The mRNA and protein expression of brown fat markers were assessed by real-time fluorescence quantitative PCR and Western blotting.Mitochondrial content was measured by real-time fluorescence quantitative PCR and Mito-Tracker Green staining.ResultsPreadipocytes treated with DHA for 2 days induced a phenotypic shift from white to brown adipose tissues.An 8-day treatment with DHA and EPA promoted the expression off brown fat marker gene,uncoupling protein 1(UCP1),and mitochondrial biogenesis as well as glucose consumption during differentiation.DHA at 100 μM reduced triglyceride content while EPA at 100 μM improved the triglyceride storge.EPA and AA manipulated mature white adipocytes to acquire brown phenotype without mitochondrial biogenesis after 2-day treatment.Unlike DHA,which exerted browning effect at the early developmental stage,EPA triggered a brown phenotype in the late stage of differentiation.ConclusionEPA,DHA and AA at 10 μM and 100μM promote browning of 3T3-L1 adipocytes and mitochondrial biogenesis as well as glucose consumption at different stages of cell differentiation.The application of PUFAs at proper time may promote browning of white adipose,which is a potential treatment approach to improve obesity.