Effects Of Duck Oil On Lipid Metabolism,Oxidative Stress And Insulin Sensitivity In Oleic Acid Induced HepG2 Cells

Objective: Non-alcoholic fatty liver disease(NAFLD)refers to the metabolic syndrome caused by other unclear factors that damage the liver except alcohol,which is mainly characterized by excessive accumulation of triglycerides in the liver of patients without a history of excessive drinking.At present,the pathogenesis of the disease is not completely clear,and the more widely accepted pathogenesis is the second blow theory.Duck oil is extracted and processed from belly fat,liver fat,subcutaneous fat and other parts of meat duck,which has certain antioxidant activity.The effect of duck oil on NAFLD has not been reported.In this paper,the physicochemical properties of duck oil,including melting point,solid fat content,fatty acid composition and content,and the crystallization characteristics of duck oil were determined firstly.In addition,Hep G2 cells were used as an study model of nonalcoholic steatohepatitis in vitro,and the experimental methods of duck oil were studied from three aspects of lipid metabolism,insulin sensitivity and oxidative stress on the prevention of NASH.Hep G2 cells were treated with 0.5m M Oleic acid(OA)for 24 h as the cell model in vitro.Hep G2 cells were treated with duck oil(0.5mg/ml,1mg/ml,2mg/ml,4mg/ml)and OA for 24 h.After treated with duck oil,the contents of Triglyceride(TG),Reactive oxygen species(ROS),SOD and MDA in cells and the ability of glucose uptake were detected.QRT-PCR was used to detect the effects of duck oil on the expression of some key genes in model cells,including key genes of glucose and lipid metabolism(sterol regulatory element-binding protein SREBP-1c,fatty acid synthase Fas,peroxisome proliferation activator receptor PPARA,glucose transporter GLUT2,protein kinase Akt)and oxidative stress phase m RNA levels of cytochrome P450 CYP1A1 and Nrf2.The protein expression levels of glucose transporter GLUT2,insulin receptor substrate IRS-1 and phosphorylated serine-threonine protein kinase Akt were detected by Western Blot in the cells.Results:(1)The melting point of duck oil was lower than the oral temperature,which gave the product a delicate feeling;The temperature in 0～15℃,with a certain plasticity;Temperature in 15 ～ 40℃ plasticity is poor,not suitable for catering oil;The main fatty acids in duck oil include stearic acid(C18:0),oleic acid(C18:1),palmitic acid(C16:0)and linoleic acid(C18:2),and the content of unsaturated fatty acids is as high as 67.83%.(2)Intracellular TG content,SREBP-1c and FAS m RNA levels were significantly increased,while PPARA m RNA levels were significantly decreased in OA treated cells;Compared with the OA treatment group,the intracellular TG content,SREBP-1c and FAS m RNA levels in the Duck oil group were significantly decreased,while the PPARA m RNA level was significantly increased.(3)Intracellular ROS and MDA contents and CYP1A1 m RNA levels were significantly increased in cells with OA compared to the group without OA,while SOD content and Nrf2 m RNA levels were significantly decreased;Compared with OA treatment group,intracellular ROS and MDA contents and CYP1A1 m RNA levels in Duck oil group were significantly decreased,while SOD content and Nrf2 m RNA levels were increased.(4)The glucose absorption and glycogen content were significantly decreased in OA treated cells,the expression of GLUT2 and p-Akt/Akt protein were down-regulated,and the expression of p-IRS-1 was up-regulated.After duck oil treatment,the glucose uptake and glycogen content of cells were increased,the expression of GLUT2 and p-Akt/Akt protein were up-regulated,and the expression of p-IRS-1 was down-regulated.Experimental conclusion: The oil extraction can extend the use range of duck oil,further utilize solid fat and liquid oil,and improve the utilization value and economic value of duck oil.Duck oil can significantly alleviate lipid accumulation,insulin resistance and oxidative stress injury in OA-induced Hep G2 cells,and has a certain preventive effect.(1)Duck oil may reduce the lipid accumulation in liver cells by inhibiting the m RNA expressions of SREBP-1c and FAS,as well as promoting the expression of PPARA,is a key gene of lipid oxidation.(2)The oxidative damage of liver cells may be alleviated by regulating the expression of reactive oxygen species related genes Nrf2 and CYP1A1.(3)Duck oil may reduce the expression levels of PEPCK and G6 Pase by regulating the expression of IRS-1/ Akt signaling pathway,alleviate insulin resistance,and then improve the glucose consumption of liver cells.