The Effect Of Finofabrate On The Expression Of Apolipoprotin A5 And The Mechanism Research Of Apolipoprotin A5 On Lipid Metabolism

Background:Lipid metabolism abnormal is an indepentend risk factor of cardiovascular diseases, its essence is the abnormal of lipoprotein and apolipoprotein. To cause atherosclerosis, the lipoprotein is more effective than cholesterol. As the protein part of lipoprotein, apolipoprotein play important role in combining and transport lipid and stabilization the construction of lipoprotein, furthermore, it adjusts protein metabolism key enzyme activity,and takes part in lipoprotein receptor identify, and plays very important role. Lipoprotein takes participate in all process of lipid human body metabolism. Before 20 years, people had identificated the most apolipoprotein which plaid very important role in lipid metabolism, 9 of which , APOA1, APOA2, APOA4, APOB48, APOB100, APOC1, APOC2, APOC3, and APOE, is most related with lipoprotein regulation. The other apolipoprotein is identificated recently, but its effect is still not known in lipid metabolism. The great discover of TG in 2001 is apoa5, one new member of apolipoprotein identificated by proteomics technique. After researched allele 1131T>C and 19S>W of apoa5, people discovered the 1131C carrier and 19W carrier had higher blood serum TG concentration than 1131T carrier and 19S carrier. The most of apolipoprotein polymorphism research show that APOA5 had the effect of lowing serum TG and regulating lipid metabolism. Because the concentration of APOA5 is approximately part per thousand of the other apolipoprotein, such as APOA1 and APOA2, its relevance and effect is not discovered directly and sufficient. The recent research discovered the effect of APOA5 is by activating LPL and accelerating VLDL catabolism. Some research also discovered transcriptional factor, such as PPARa, RORa, LXR and SREBP-1c, had regulated and supported it to low lipid. But the mechanism research of APOA5 is still less, and it is argumented that the precisely mechanism of APOA5 regulation lipid metabolism, the internal and external correlated report is less. So research of APOA5 step by step will supply a new way for improving lipid metabolism, and supply the primary prevention of cardivascular diseases, such as CHD.Objective :Determination serum blood fat indexes and LPL activity of each group, detected the expression of APOA5 and PPAR-α in hepar, analysised the change of APOA5 gene expression and the relation with the other indexes during applying fenofibrate regulation lipid metabolism. During fenofibrate regulation lipid metabolism mechanism, discover what role APOA5 played.Methods :Fouty male Wister rats were randomly devided into four groups: control group, model group, high-dose fenofibrate and low-dose fenobibrate group. During the whole experiment, the rats in control group were fed with normal food, and the rats in the in others were fed with a high caloric laboratory chow. After continuous feeding 4 weeks, the rats in high-dose fenofibrate and low-dose fenobibrate group were given fenofibrate 100mg/kg, 35mg/kg intragastric administration, while the ones in the other groups were given Sodium Chloride . After 4 weeks, adopting blood samples and liver homogenate to detect triglyceride( TG) and total cholesterol (TC), extracting hepar mRNA and applying RT-PCR method to detect APOA5 and PPAR-α expression, as well as analyzing the relation of APOA5 and PPAR-α, TG , TC.clinical research: 174 subjects were divided to 2 groups. The 67 subjects of CHD were the patient in the deartment of health and internal medicine of SanDong university and QiLu hospital, the 107 subjects of control group were the healthy examination people of health pretection out-patient clinic. All subjects were draw blood 5ml form ulnar vein on an empty stomach in early morning and remained serum. 1ml serum was preserved in -80 ℃ for APOA5 determination, and the other serum were detected for blood fat, lipoprotein, apolipoprotein. To analyze the relative between APOA5 and blood fat, lipoprotein discovered the effect of APOA5 in lipid metabolism and CHD.Statistical treatment: all data will be dealed with by SPSS13.0 statistics software, and all data demonstrated by x±s, group comparison by analysis of variance, two groups comparison by LSD test. APOA5 compare with the other indexes by Correlation analysis.Results :1. Foundation experiment: ①It had no statistics discrepancy between different group in the firstdetection.Campare with baseline determination value, after 4 weeks the serum TC, TG, LDL concentration of rats in model group, high-dose fenofibrate and low-dose fenobibrate group were higher, serum HDL was lower. The control group had no obviously different. ②After 4 weeks medicine dealed with, TG concentration of rats in model group was higher than these of rats before medicine applying, and higher than these of rats in control group, too. (p<0. 01). Give high or low dose finofibrate in advance, it all could significant improve the serum TG of hyperlipemia rat, dose dependency, and it influence serum TC, HDL, LDL concetration. The same result coule be discovered in liver homogenate. The expression of APOA5 in model group was obviously higher than that in control group. Fenofibrate increased significantly the expression of APOA5 and PPARα mRNA of hyperlipoidemia rat liver, and increased plasm LPL activity. The mRNA expression of serum TG, APOA5 PPARα and LPL activity in high fenofibrate group have no discrepancy with that in normal comtrol. The correlation analysis show that the expression of APOA5 mRNA is negative correlation with serum TG and liver homogenate TG (p<0.01) , and positive correlation with PPARα mRNA (p<0. 01) , positive correlation with LPL activity (p<0. 05) . APOA5 have no obviously correlation with TC serum and liver homogenate TG.2. clinical experiment ① The APOA5 and ANPin control group is obviously lower than those in CHD group, TC/TG/LDL-C in control group is obviously highr than those in CHD group. And the patients in CHD group were divide into 2 groups by serum TG: CHD with high TG and CHD with normal TG.APOA5 of patients in the two groups all lower than that in normal control group (p<0. 01) , APOA5 of patients in CHD with high TG is obviusly lower than that in CHD with normal TG. The same change was discovered in ANP. ②APOA5 of patient in high TG group was lower than that in normal control group. APOA5 of patient in high TC had no difference with that in normal control group. (3)The correlation analysis show that APOA5 is negative correlation with serum TG and ANP and LDL (p<0.01 or p<0.05) ; serum ANP is negative correlation with TG, TC (p<0.01) , positive correlation with HDL (p<0.05) .Conclusion :1. Finofibrate regulated up the expression of APOA5 gene and PPARαa, which displayed dose dependent. The expression of APOA5 gene had obviously relation with LPL actiovity. The expression of APOA5 gene is the important factor in serum TG metabolism. Finofibrate regulated blood fat maybe partly by PPARα ligand action. APOA5 could play an important role in finofibrate regulating blood fat.2. Serum APOA5 could be the important factor for TG metabolism.The low serum APOA5 could be the risk factor for coronary artery disease. Serum APOA5 had positive relation with ANP. APOA5 could have synergism with ANP in the onset process of CHD, the mechanism of APOA5 action have relation with ANP.