Study On Injury Of OxLDL On Coronary Artery Endothelial Cells And Its Mechanism

Coronary atherosclerosis refers to atherosclerosis occurring in the coronary arteries,characterized by plaque formation and plaque erosion,rupture,thrombosis leading to severe cardiovascular events such as myocardial ischemia and myocardial infarction..It is currently believed that vascular coronary artery endothelial injury is the starting point.Hypertension,smoking,dyslipidemia,diabetes and obesity,and chronic cardiovascular risk factors such as vascular endothelial injury or the associated harmful circulatory stimuli,can destroy the vascular endothelium and affect endothelial integrity,causing vascular endothelial stability Disorders and dysfunction,vasoconstriction,oxidative stress,thrombosis,inflammatory response,etc.,activate downstream signaling pathways,and a series of molecular,cellular,and vascular wall structures related to atherosclerotic vascular remodeling.Block formation even its sequelae,such as myocardial ischemia,myocardial infarction.Oxidized low density lipoprotein(OxLDL)can cause a variety of vascular endothelial damage,leading to its functional destruction,involved in the initiation and progression of atherosclerosis,played in the early stages of atherosclerosis The core role.As a blood vessel that directly supplies blood to the heart,the coronary artery has different characteristics from other arterial endothelial cells,and the coronary artery is a region with high atherosclerosis and has serious consequences.At present,the mechanism of OxLDL damage to coronary artery endothelial cells is still unclear.Therefore,it is of great significance to further investigate the damage of OxLDL to coronary endothelial cell function and its specific mechanism.Objective: 1.Identify the functional damage and gene expression differences of OxLDL on coronary endothelial cells;2.To investigate the effect and mechanism of p21 protein on cell function damage in OxLDL-induced coronary endothelial injury.Methods: 1.Using vascular tone to detect the effect of OxLDL on the endothelial diastolic function of coronary and mesenteric artery in rats;2.Using CCK-8 and scratch test to test the proliferation and migration ability of HCAECs cells;3.Using TUNEL method to detect the apoptosis level of HCAECs;4.The HDL kit detects the LDH level in the supernatant of HCAECs;5.The RNA-seq method was used to sequence the whole transcript and analyze the differential genes between the groups after 24 hours of treatment with OxLDL: 6.Using the String and KEGG database significant differential genes for signal transduction pathway analysis and signal pathway regulation network construction;7.Detection of proteins related to differential genes by Western blot(WB).Results: 1.Vascular tension experiments suggest that OxLDL can attenuate the endothelium-dependent vasodilation function of coronary and mesenteric arteries in rats;2.Cell scratches,CCK-8 and cell supernatant HDL assays showed that after OxLDL treatment of HCAECs,cell migration and proliferation ability were significantly inhibited,and cell supernatant HDL levels increased.3.TUNEL and Western blot experiments showed that the apoptosis rate of HCAECs was significantly increased after OxLDL treatment,and the apoptosis-related protein changes were consistent with the apoptosis level.4.Transcriptome sequencing(RNA-Seq)found that after treatment of HCAECs with OxLDL for 24 h,979 genes were differentially expressed,of which 130 genes were known genes,70 genes were up-regulated,and 60 genes were down-regulated;by String and KEGG The database analysis showed that CDKN1A(target protein p21)and integrin-related genes are involved in cell cycle regulation and migration and may play an important role;5.After treatment with OxLDL,the expression level of p21 protein increased significantly at 24 h,but decreased at 72 h.The pretreatment of p21-siRNA significantly enhanced OxLDL-induced apoptosis at 24 h,but at 72 h There was no significant difference;p21-siRNA pretreatment inhibited cell proliferation of HCAECs.Conclusion: 1.1.OxLDL can cause damage to coronary endothelial cells;2.Up-regulation of p21 protein expression in HCAECs induced by early OxLDL may be a stress-protecting mechanism of cell anti-apoptosis;while down-regulation of p21 protein expression may be one of the key factors for OxLDL-induced apoptosis.3.Up-regulation of p21 protein expression in HCAECs induced by early OxLDL is not a major factor in inhibiting cell proliferation,and regulation of the integrin pathway may play a key role.