Effect Of Vitamin D On Lipid Deposition Of Human Hepatocellular Carcinoma Cell(HepG2) Induced By Oleic Acid

Objective:Steatosis of liver cells is one of the important pathological changes that affect the liver function.The main characteristic of fatty liver caused by fatty liver is the pathological change caused by excessive accumulation of fat in the liver.It is a common pathological change of the liver,which will seriously lead to the disorder of liver function and various system functions of the whole body.As one of the fat soluble vitamins,vitamin D has a positive effect on human health,which has been confirmed in many aspects,and its effect on lipid metabolism has also been confirmed by many studies.The purpose of this study is to study the effect of vitamin D on the lipid accumulation of hepatocytes,and to provide a basis for further study of its mechanism.Methods:The research object is HepG2 cell line.The experiment is divided into three groups: control group(CON group),treatment group(VD group),oleic acid treatment group(OA group),active vitamin D and oleic acid co treatment group(OA+VD group).AST and ALT in the lysate are detected by kit Level,TG,TC,Glu.The changes of lipid droplets and lipid deposition in hepatocytes were observed by oil red O staining.The expression of VDR,PPAR ?,CD36,MTTP and PGC-1 ? in HepG2 cells was detected by RT-qPCR.Western blot,immunohistochemistry and immunofluorescence were used to detect the expression of CD36,PPAR ?,PGC-1 ? and MTTP in HepG2 cells.Results: After treatment with oleic acid and active vitamin D,1.Under the induction of oleic acid,the contents of total cholesterol,triglyceride and glucose in Hep G2 cells were significantly increased.At the same time,in the OA+VD group,the contents of TC and TG were significantly higher than that in the oleic acid group,and the results were statistically significant,but the content of Glu was not higher than that in the oleic acid group.2.By oil red O staining,it can be seen that compared with the blank group,the amount of lipid drops in cells treated with oleic acid and active vitamin D increased significantly,and the increase of lipid drops was positively correlated with the concentration of active vitamin D.Through the quantitative analysis of oil red O staining,we found that the amount of lipid drops in cells treated with oleic acid and active vitamin D increased significantly,the difference was statistically significant.When treated with oleic acid alone,the amount of lipid droplets in the cells increased with the increase of time;under the same conditions,the amount of lipid droplets in the cells would continue to increase with the increase of active vitamin D treatment,and it was positively correlated with time.Through the quantitative analysis of oil red O staining,it was found that the amount of lipid droplets increased with the increase of time after the treatment of oleic acid and active vitamin D,and after the quantitative comparison,the amount of lipid droplets was the most after 24 hours treatment.3.Compared with the con group,the expression of CD36,PPAR ?,PGC-1 ? protein and mRNA in the OA group was significantly increased,while the expression of CD36,PPAR ?,PGC-1 ? protein and mRNA in the OA+VD group was also significantly increased,the difference was statistically significant.Compared with the con group,the expression of MTTP protein in the OA group was decreased,and the down-regulation of mRNA was not significant,while the expression of MTTP protein and mRNA in the OA+VD group was lower the tone is more pronounced.4.Compared with con group,AST in OA group increased significantly,while AST in OA+VD group decreased significantly,the difference was statistically significant;however,the influence of four groups with the same treatment factors on ALT was not significant,and the difference was not statistically significant.Conclusion:1.Active vitamin D(Calcitriol)can increase the expression of VDR in HepG2 cells,and may have a protective effect on liver function of HepG2 cells;2.Active vitamin D can increase the fatty acids entering HepG2 cells,and cause lipid accumulation;3.Active vitamin D can promote the expression of CD36,PPAR?and PGC-1 ? in HepG2 cells,increase the fatty acids in HepG2 cells,and promote the deposition of these fatty acids 4.Active vitamin D can down regulate the expression of MTTP in HepG2 cells,which may reduce the transport of lipid out of hepatocytes,resulting in the increase of intracellular lipid accumulation.In conclusion,vitamin D increased lipid deposition in HepG2 cells induced by oleic acid.