Study On The Mechanism Of Oxidized Low Density Lipoprotein Promote Smooth Muscle Cell-derived Foam Cell Necrosis Through ROS

Background and PurposeWorldwide,cardiovascular diseases and other critical illnesses,as the first cause of death in the world,have seriously threatened human health.The most important pathological basis is atherosclerosis.In recent years,with experts’in-depth research on the mechanism of atherosclerosis,we have discovered that foam cells,as a key cell type in the development of atherosclerosis,have an important role in the progression of AS.Especially in the middle and late stages of AS,the number of foam cells derived from smooth muscle cells accounts for a greater proportion.At the same time,a large number of studies have found that the oxidative modification of low-density lipoprotein plays an important role in the occurrence and development of AS.ox-LDL is one of the most important factors in the continuous damage of the arterial wall,and it has been confirmed that it has a key role in the programmed necrosis of macrophage-derived foam cells.ox-LDL induces many downstream signal transduction events including the production of ROS.Whether ox-LDL can induce the necroptosis of smooth muscle cell-derived foam cells and its specific mechanism remain unclear.This topic aims to study the effect of ox-LDL on the necroptosis of smooth muscle cell-derived foam cells,explore its possible mechanism of action,and provide a basis for the treatment of atherosclerosis.MethodsSmooth muscle cells were treated with 5ug/ml cholesterol for 72 hours to obtain a smooth muscle-derived foam cell model.With smooth muscle cell-derived foam cells as target cells,different concentrations of ox-LDL and Tempol were treated for24 hours.CCK-8 and LDH methods were used to detect the survival rate of smooth muscle-derived foam cells and ox-LDL cytotoxicity;Mito SOX^TMRed mitochondrial superoxide detection kit was used to detect intracellular mitochondrial ROS levels;JC-1 fluorescent staining was used to detect foam cell mitochondrial membrane potential Use Annexin V/PI double staining flow cytometry to detect the mortality of each group of cells;use transmission electron microscope to observe the ultrastructure of each group of cells.Resultsox-LDL induces smooth muscle cell-derived foam cell death in a concentration-dependent manner;promotes the abnormal accumulation of mt ROS in the cell;leads to a decrease in mitochondrial membrane potential.Observation of smooth muscle cell-derived foam cells treated with ox-LDL by electron microscope,and found that ox-LDL can cause typical signs of cell necroptosis,namely swelling of the nucleus,increase in cell volume,destruction of cell membrane integrity,and swelling of organelles;use Annexin V/PI Double staining test confirmed that ox-LDL induced smooth muscle cell-derived foam cells to undergo necroptosis.After treatment with the superoxide dismutase analogue Tempol,it can significantly reduce the abnormal accumulation of mt ROS in the cell,inhibit the decline of mitochondrial membrane potential,and significantly reduce the ox-LDL-induced smooth muscle cell-derived foam cell necroptosis.Conclusionox-LDL induces the occurrence of cell necroptosis by promoting the abnormal accumulation of mt ROS in smooth muscle cell-derived foam cells.