The Researches On Browning Of Murine Adipose Tissue Induced By Large-leaf Yellow Tea

The high-fat diet structure of modern people makes their bodies’ energy intake level exceed their energy consumption level for a long time,causing abnormal energy accumulation and imbalance of energy metabolism,which leads to an obesity epidemic,which in turn induces the occurrence of metabolic syndrome such as obesity,diabetes,hypertension,fatty liver,cardiovascular and cerebrovascular diseases.Large-leaf yellow tea is an unique product of Anhui.Our previous studies proved that it has the effect of lowering blood gluose,regulating blood lipids,and improving diabetes,but its effect on regulating energy metabolism has not been studied.This study explored the role of dietary supplementation of large-leaf yellow tea extract(YT)in regulating the energy metabolism of high-fat diet mice and inducing heterogeneous browning of three typical fat pads.Thirty-two 5-week-old C57BL/6 male mice were randomly divided into 4 groups,each with a different diet: low-fat group(LFD),high-fat group(HFD),HFD+0.5%YT and HFD+2.5%YT for 12 weeks,and their physiological indicators(weight,diet,drinking water)were measured.After 10 weeks of YT intervention,these mice were subjected to automatic metabolic cage testing.After 12 weeks of intervention,these mice were sacrificed,and their blood,liver,brown fat,subcutaneous fat and epididymal fat samples were taken in order to carry out the following research work.1)After 12 weeks of intervention,YT significantly reduced the body weight,liver weight and lipids accumulation of mice compared with the model group(HFD).It also effectively regulates hormone levels of specific to fat tissue in the serum,including lowering Leptin and increasing Adiponectin levels.2)Metabolic monitoring of mice showed that YT treatment significantly increased oxygen consumption,carbon dioxide production,respiratory exchange rate and heat production in mice.Furthermore,consistent with body temperature monitoring,YT significantly increased the core body temperature of mice.3)H&E staining showed that YT intervention induced the appearance of multi-chamber brown-like cells in subcutaneous adipose tissue(SAT)and brown adipose tissue(BAT),inducing the browning transition of the two fat pads.Immunohistochemical analysis showed that YT significantly increased the expression level of UCP1 in BAT and SAT.q PCR and WB analysis showed that YT induced upregulation of thermogenesis regulator m RNA(UCP1,PGC1α,Prdm16,Elovl3,Cidea)and protein(SIRT1,PGC1α and UCP1)in three fat pads,indicating that YT activated the thermogenesis program.4)Separating the stromal vascular phases of brown fat and subcutaneous fat and adding YT intervention during the induction differentiation process showed that YT significantly enhanced the differentiation of primary subcutaneous preadipocytes into mature brown-like adipocytes,indicating that YT can directly induce the differentiation of brown-like adipocytes.5)The m RNA expressions of typical brown fat cell markers(Zic1,Eva1)and beige fat cell markers(Tbx1,Tmem26)were detected separately,and it was found that after YT intervention,Zic1 and Eva1 were only significantly increased in BAT,while Tbx1 and Tmem26 levels significantly increased only in SAT.All markers were unchanged in epididymal adipose tissue(EAT).6)Detection of the mitochondrial membrane marker protein ATP5 A found that YT up-regulated ATP5 A levels in all three tissues,which significantly increased mitochondrial copy number and induced mitochondrial biogenesis.In summary,dietary supplement YT prevents obesity and chronic metabolic disorders induced by high-fat diets through regulating adaptive thermogenesis and increasing energy expenditure.YT intervention has a heterogeneous effect on three typical fat pads,inducing classical palm fat cells in BAT and beige fat production in SAT.Although EAT did not induce browning transformation,it enhanced the mitochondrial biogenesis pathway.This research work provides new ideas for nutrition intervention for obesity and diabetes prevention and management.It also gives the cheap large-leaf yellow tea new health connotations,thus providing theoretical and practical supports for the development and utilization of Anhui specialty tea resources.