Influence of Oxidized Low Density Lipoprotein on the Proliferation of Human Artery Smooth Muscle Cells in vitro

The effects of oxidized low density lipoprotein （ox-LDL） on the proliferation of cultured human vascular smooth muscle cells （vSMC） were investigated in vitro. By using NaBr density gradient centrifugation, LDL was isolated and purified from human plasma. Ox-LDL was produced from LDL by being incubated with CuSO4. ox-LDL was then added to the culture medium at different concentrations （35, 60, 85, 110, 135 and 160μg/mL） for 7 days. The influence of ox-LDL on vSMC proliferation was observed in growth curve, mitosis index, and in situ determination of apoptosis. The data were analyzed with SPSS 10.0 software. The results showed that the ox-LDL produced in vitro had a good purity and optimal oxidative degree, which was similar to the intrinsic ox-LDL in atherosclerotic plaque, ox-LDL at a concentration of 35 μg/mL demonstrated the strongest proliferation inducement, and at a concentration of 135 μg/mL, ox-LDL could inhibit the growth of vSMC. ox-LDL at concentrations of 35 and 50 μg/mL presented powerful mitotic trigger, and with the increase of ox-LDL concentration, the mitotic index of vSMC was decreased gradually, ox-LDL at higher concentrations promoted more apoptotic vSMCs, ox-LDL at lower concentrations triggered proliferation of vSMCs, and at higher concentrations induced apoptosis in vSMCs, ox-LDL played a promotional role in the pathogenesis and development of atherosclerosis by affecting vSMC proliferation and apoptosis.

Effects of Oxidized Low Density Lipoprotein on Transformation of Valvular Myofibroblasts to Osteoblast-like Phenotype

In order to investigate the roles of Wnt signal pathway in transformation of cardiac valvular myofibroblasts to the osteoblast-like phenotype, the primary cultured porcine aortic valve myofibroblasts were incubated with oxidized low density lipoprotein（ox-LDL, 50 mg/L）, and divided into four groups according to the ox-LDL treatment time： control group, ox-LDL 24-h group, ox-LDL 48-h group, and ox-LDL 72-h group. Wnt signal pathway blocker Dickkopf-1（DDK-1, 100 μg/L） was added in ox-LDL 72-h group. The expression of α-smooth muscle actin（α-SMA）, bone morphogenetic protein 2（BMP2）, alkaline phosphatase（ALP）, and osteogenic transcription factor Cbfa-1 was detected by Western blotting, and that of β-catenin, a key mediator of Wnt signal pathway by immunocytochemical staining method. The Wnt/β-catenin was observed and the transformation of myofibroblasts to the osteoblast-like phenotype was examined. The expression of α-SMA, BMP2, ALP and Cbfa-1 proteins in the control group was weaker than in the ox-LDL-treated groups. In ox-LDL-treated groups, the protein expression of α-SMA, BMP2, ALP, and Cbfa-1 was significantly increased in a time-dependent manner as compared with the control group, and there was significant difference among the three ox-LDL-treated groups（P〈0.05 for all）; β-catenin protein was also up-regulated in the ox-LDL-treated groups in a time-dependent manner as compared with the control group（P〈0.05）, and its transfer from cytoplasm to nucleus and accumulation in the nucleus were increased in the same fashion（P〈0.05）. After addition of DKK-1, the expression of α-SMA, bone-related proteins and β-catenin protein was significantly reduced as compared with ox-LDL 72-h group（P〈0.05）. The Wnt/ β-catenin signaling pathway may play an important role in transformation of valvular myofibroblasts to the osteoblast-like phenotype.

Role of PERK/eIF2α/CHOP Endoplasmic Reticulum Stress Pathway in Oxidized Low-density Lipoprotein Mediated Induction of Endothelial Apoptosis

Objective PERK/elF2/CHOP is a major signaling pathway mediating endoplasmic reticulum （ER） stress related with atherosclerosis. Oxidized LDL （ox-LDL） also induces endothelial apoptosis and plays a vital role in the initiation and progression of atherosclerosis. The present study was conducted to explore the regulatory effect of ox-LDL on PERK/elF2a/CHOP signaling pathway in vascular endothelial cells. Methods The effects of ox-LDL on PERK and p-elF2a protein expression of primary human umbilical vein endothelial cells （HUVECs） were investigated by Western blot analysis. PERK gene silencing and selective elF2a phosphatase inhibitor, salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis, caspase-3 activity, and CHOP mRNA level. Results Ox-LDL treatment significantly increased the expression of PERK, PERK-mediated inactivation of elF2a phosphorylation, and the expression of CHOP, as well as the caspase-3 activity and apoptosis. The effects of ox-LDL were markedly decreased by knocking down PERK with stable transduction of lentiviral shRNA or by selective elF2a phosphatase inhibitor, salubrinal. Conclusion This study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/elF2a/CHOP ER-stress pathway. It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.

Expression of Monocyte Chemoattractant Protein-1 in Monocytes and Effects of Native and Oxidized Very Low Density Lipoproteins

Monocyte chemoattractant protein-1(MCP-1), a potent chemoattractant, is thought to play an important role in migration of monocytes into atherosclerotic lesions. The present study was designed to investigate the capacity of human peripheral blood monocytes to express MCP-1 and effects of native very low density lipoprotein (VLDL) and oxidized VLDL(OX-VLDL) on the expression. The total RNA was extracted from cultured monocytes, which were exposed to VLDL and OX-VLDL, and the media conditioned by monocytes were collected. MCP-1 mRNA expression was examined by Northern blot analysis. MCP-1 protein in conditioned media was determined by using sandwich ELISA. The results showed that monocytes can express MCP-1 after a 24 h incubation at 37℃，and the expression was markedly increased by a exposure to OX-VLDL, whereas the expression was slightly increased when exposed to VLDL. It suggests that the capacity of monocytes to produce MCP-1 that recruits and activates circulating monocytes may be of considerable importance in atherogenesis, and oxidation of VLDL enhances its potential to promote atherogenesis.

Obstructive jaundice leads to accumulation of oxidized low density lipoprotein in human liver tissue

Oxidized low density lipoprotein （ox-LDL） molecule is one of the most important modified lipoproteins produced during the oxidative stress. Modified lipoproteins have been defined as being part of the immune inflammatory mechanisms in association with oxidant stress. We have reported the accumulation of ox-LDL in Balb/c mice liver after bile duct ligation previously. Here, we investigated this finding in human beings with obstructive jaundice. Our study demonstrates that obstructive jaundice results in tremendous accumulation of ox-LDL in the liver tissue of patients.

Anti-oxidized low-density lipoprotein antibodies in chronic heart failure

Oxidative stress may play a significant role in the pathogenesis of heart failure(HF).Antibodies to oxidized low-density lipoprotein(oxLDL Abs) reflect an immune response to LDL over a prolonged period and may represent long-term oxidative stress in HF.The oxLDL plasma level is a useful predictor of mortality in HF patients,and measurement of the oxLDL Abs level may allow better management of those patients.Antibodies to oxLDL also significantly correlate with the New York Heart Association score.Hypercholesterolemia,smoking,hypertension,and obesity are risk factors for atherosclerotic coronary heart disease(CHD) leading to HF,but these factors account for only onehalf of all cases,and understanding of the pathologic process underlying HF remains incomplete.Nutrients with antioxidant properties can reduce the susceptibility of LDL to oxidation.Antioxidant therapy may be an adjunct to lipid-lowering,angiotensin converting enzyme inhibition and metformin(in diabetes) therapy for the greatest impact on CHD and HF.Observational data suggest a protective effect of antioxidant supple-mentation on the incidence of HD.This review summarizes the data on oxLDL Abs as a predictor of morbidity and mortality in HF patients.

Oxidized low density lipoprotein (Ox-LDL) impacts on erythrocyte viscoelasticity and its molecular mechanism

Aim:The oxidized low-density lipoprotein(OxLDL) plays an important role in atherosclerosis yet it remains unclear if it damages circulating erythrocytes. Method: In this study。

Protein in oxidized low density lipoprotein may cause injury to mitochondria of mouse peritoneal macrophages

Injury to mitochondria of macrophages caused by oxidized low density lipoprotein (Ox-LDL) and the role of lipid hydroperoxides (LOOH). lipid and protein in Ox-LDL on the injury were studied by measuring mito-chondrial membrane potential (MMP) on ACAS570. The results showed that MMP decreased when macrophageswere treated by Ox-LDL. If LOOH in Ox-LDL was pre cleared by ebselen plus GSH. the decreased MMP could be recovered by about 20 %. Lipid moiety alone had no effect on IMP, but protein moiety could cause decrease ofMMP, the extent of the decrease was equivalent to that caused by Ox-LDL in which LOOH was pre-cleared by ebselen plus GSH.

EC,ASMC and Macrophage Oxidize Human Low Density Lipoprotein

To investigate the mechanism of LDL oxidation i n vivo , LDL was incubated with endothelium cell (EC),artery smooth muscle cel l (ASMC) and macrophage, and then the change of myeloperoxidase (MPO) activity i n cell and medium and the oxidation of LDL by those three cells were assessed. T he result showed that LDL promoted the activity of cellular and secretive myelop eroxidase which was concentration\|dependent on LDL; with elevation of MPO activ ity, oxidation of LDL intensified, which was expressed by the formation of conju gated dienes and the elevation of thiobarbituric acid teactive substance (TBARS ). Macrophage's MPO activity went up with the increase of LDL at both low and h igh concentration; EC's MPO activity went up with the increase of LDL only at h igh concentration and ASMC's MPO activity wasn't sensitive to LDL concentratio n change. The results suggest that Macrophage might be crucial to the oxidation of LDL in vivo , in which MPO might play an important role.

Inhibition of Oxidative Modification of Human Low Density Lipoprotein by Resveratrol

To further investigate whether resveratrol, a polyphenolic compound in red wine, affects the oxidation of human low density lipoprotein (LDL), LDL purified from normolipidemic subjects was subjected to Cu\+\{2+\}induced or azo compoundinitiated oxidative modification. The extent of LDL modification was assessed by measuring the formation of thiobarbituric acid reactive substances (TBARS) and the relative electrophoretic mobilities (REM) of LDL. Resveratrol (50 mol/L) reduced TBARS and REM of LDL during Cu\+\{2+\}induced oxidation by 70.5% and 42.3%, respectively (P<0.01), and prolonged the lag phase associated with the oxidative modification of LDL by copper ion or azo compound. These in vitro results suggest that resveratrol may afford LDL protection against oxidative modification, possibly by acting as a free radical scavenger.

Mitofusin2 Decreases Intracellular Cholesterol of Oxidized LDL-Induced Foam Cells from Rat Vascular Smooth Muscle Cells

Mitofusin2 （Mfn2） plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells （VSMCs）. The purpose of this study was to investigate the effects of Mfn2 on the traffick- ing of intracellular cholesterol in the foam ceils derived from rat VSMCs （rVSMCs） and also to investigate the effects of Mfn2 on the expression of adenosine triphosphate-binding cassette subfamily A member 1 （ABCA1）, adenosine triphosphate-binding cassette subfamily G member 1 （ABCG1） and peroxisome proliferator-activated receptor gamma （PPARy）. The rVSMCs were co-cultured with oxi- dized low density lipoprotein （LDL, 80 ~tg/mL） to produce foam cells and cholesterol accumulation in cells. Before oxidized LDL treatment, different titers （20, 40 and 60 pfu/cell） of recombinant adenovirus containing Mfn2 gene （Adv-Mfn2） were added into the culture medium for 24 h to transfect the Mfn2 gene into the rVSMCs. Then the cells were harvested for analyses. The protein expression of Mfn2 was significantly higher in Adv-Mfn2-transfected group than in untransfected group （P〈0.05）, and the ex- pression levels significantly increased when the titer of Adv-Mfn2 increased （P〈0.05）. At 24 or 48 h af- ter oxidized LDL treatment, rVSMCs became irregular and their nuclei became larger, and their plasma abounded with red lipid droplets. However, the number of red lipid droplets was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group. At 48 h after oxidized LDL treatment, the intracellular cholesterol in rVSMCs was significantly increased （P〈0.05）, but it was sig- nificantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）, and it also significantly decreased when the titer of Adv-Mfn2 increased （P〈0.05）. The mRNA and pro- tein expression levels of ABCA1 and ABCG1 were significantly increased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. Though the mRNA and protein expression levels of PPARy was not significantly increased （P〉0.05）, the phosporylation levels of PPARy were signifi- cantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. These results suggest that the transfection of Adv-Mfn2 can significantly reduce intracellular cholesterol in oxidized LDL-induced rVSMCs possibly by decreasing PPAR＇/phosporylation and then increasing pro- tein expression levels of ABCAI and ABCG1, which may be helpful to suppress the formation of foam cells.

EFFECT OF OXIDIZED-LDL ON NF-κB NUCLEAR TRANSLOCATION IN AORTIC SMOOTH MUSCLE CELLS ORIGINATED FROM RATS OF DIFFERENT AGES

Objective To investigate the molecular mechanism of atherosclerosis that related to age. Methods Immunohistochemistry staining and Western blot were adopted to determine the nuclear translocation of nuclear factor-kappa B (NF-κB) and expression of platelet-derived growth factor B (PDGF-B) in smooth muscle cells (SMCs) co-cultured with low density lipoprotein (LDL), oxidized LDL (ox-LDL), and ox-LDL+high density lipoprotein (HDL) originated from rats of 2 and 10 months old respectively. Fat stain was used to identify the lipid intake in SMCs. Results The optimal stimulation time of ox-LDL to SMCs was 12 hours. NF-κB intensity increased in most nuclei of SMCs that originated from rats of either 2 or 10 months old co-cultured with ox-LDL. The intensity of NF-κB and the amount of intracellular lipid taken in SMCs were more obvious in cells from 10-month-old rats than from the younger ones. Change of PDGF-B expression in SMCs was not remarkable in each group of rats. Conclusions The 10-month-old rats are more susceptive to ox-LDL than 2-month-old rats in activating nuclear transloca- tion of NF-κB. Maybe this is one of the important reasons contributing to the difference between the older and younger rats on the initiation and development of atherosclerosis lesion. Expression of PDGF-B is not associated with the activity of nuclear translocation of NF-κB.

基于NOD样受体3炎性小体通路对利拉鲁肽在氧化低密度脂蛋白诱导内皮细胞损伤的作用机制研究

背景动脉粥样硬化是世界范围内引起心脑血管疾病最主要的原因,炎症是目前研究热点,其中NOD样受体3(NLRP3)是研究最为深入的炎症小体。胰高糖素样肽1(GLP-1)受体激动剂有抗动脉粥样硬化作用,具体机制尚不明确。目的研究利拉鲁肽通过拮抗氧化低密度脂蛋白(ox-LDL)诱导的内皮细胞损伤的作用机制。方法2022-03-25—05-19培养人脐静脉内皮细胞(HUVEC),取HUVEC加空白血清作为对照组,100μg/mL的ox-LDL干预HUVEC 48 h作为模型组,100μg/mL的ox-LDL干预HUVEC 24 h后分别加入100、200、400 nmol/L利拉鲁肽处理24 h作为利拉鲁肽低浓度组、利拉鲁肽中浓度组、利拉鲁肽高浓度组。CCK-8法计算细胞增殖率。通过扫描电镜观察焦亡细胞形态。检测乳酸脱氢酶(LDH)活力。酶联免疫吸附试验(ELISA)检测白介素(IL)-1β、IL-18表达水平。蛋白质免疫印迹试验(Western blot)检测NLRP3、接头蛋白凋亡相关斑点样蛋白(ASC)、天冬氨酸蛋白水解酶1(Caspase-1)、焦亡执行蛋白(GSDMD)、N端结构域的焦亡执行蛋白(N-GSDMD)表达水平。结果模型组、利拉鲁肽低浓度组和利拉鲁肽中浓度组细胞增殖率低于对照组,利拉鲁肽低浓度组、利拉鲁肽中浓度组、利拉鲁肽高浓度组细胞增殖率高于模型组(P<0.05)。细胞扫描电镜结果示模型组细胞焦亡明显,利拉鲁肽低浓度组、利拉鲁肽中浓度组、利拉鲁肽高浓度组细胞焦亡情况明显改善。模型组、利拉鲁肽低浓度组LDH活力高于对照组,利拉鲁肽低浓度组、利拉鲁肽中浓度组、利拉鲁肽高浓度组低于模型组(P<0.05)。模型组、利拉鲁肽低浓度组IL-1β表达水平高于对照组,利拉鲁肽中浓度组、利拉鲁肽高浓度组IL-1β表达水平低于模型组(P<0.05);模型组IL-18表达水平高于对照组,利拉鲁肽低浓度组、利拉鲁肽中浓度组、利拉鲁肽高浓度组IL-18表达水平低于模型组(P<0.05)。模型组NLRP3、ASC、Caspase-1、GSDMD、N-GSDMD表达水平高于对照组,利拉鲁肽低浓度组ASC、Caspase-1表达水平高于对照组,利拉鲁肽中浓度组NLRP3、ASC表达水平低于模型组,利拉鲁肽高浓度组NLRP3、ASC、Caspase-1表达水平低于模型组(P<0.05)。结论利拉鲁肽显著抑制ox-LDL诱导的内皮细胞NLRP3炎性小体活化,并且能够抑制内皮细胞的焦亡,具有抗动脉粥样硬化作用。

Effects of oxidized low density lipoprotein on the growth of human artery smooth muscle cells

Background Studies have shown that oxidized low density lipoprotein （ox-LDL） promotes the pathogenesis and development of atherosclerosis （AS）, and that the proliferation, migration and phenotype alteration of vascular smooth muscle cells （vSMCs） into foam cells are critical changes in AS. It is proposed that ox-LDL might play a novel role in the pathologic process of vSMCs. The present study was performed ex vivo to investigate the effects of ox-LDL on the growth of cultured human vSMCs.Methods Using NaBr density gradient centrifugation, LDL from human plasma was isolated and purified. ox-LDL was produced from LDL after being incubated with CuSO4. ox-LDL was then added to the culture medium at different concentrations （25μg/ml, 50μg/ml, 75 μg/ml, 100μg/ml, 125μg/ml, and 150μg/ ml） for 7 days. The influence of ox-LDL on vSMC growth was observed from several aspects as growth curve, mitosis index, lipid staining, and in situ determination of apoptosis. The digital results were analyzed with SPSS 10.0.Results The ox-LDL produced ex vivo had a good purity and optimal oxidative degree, which was similar to the intrinsic ox-LDL in atherosclerotic plaque, ox-LDL at a concentration of 25 μg,/ml demonstrated the strongest proliferation. At the concentration of 125 μg,/ml, ox-LDL suppressed the growth of vSMCs. At concentrations of 25 μg/ml and 50 μg/ml, ox-LDL presented powerful mitotic trigger. When the concentration of ox-LDL increased, the mitotic index of vSMCs decreased gradually, ox-LDL induced more foam cells from vSMCs with rich intracellular lipid accumulation at concentrations of 25μg/ml and 50μg/ml, ox-LDL at higher concentrations induced more apoptotic vSMCs.Conclusions ox-LDL at lower concentrations may trigger proliferation and phenotype alteration into foam cells of vSMCs, and at higher concentrations it may induce apoptosis in vSMCs, ox-LDL plays an important role in the pathogenesis and development of atherosclerosis by its effect on vSMCs proliferation, phenotype alteration and apoptosis.

Association between circulating oxidized low-density lipoprotein and atherosclerotic cardiovascular disease

Atherosclerosis is a chronic, progressive disease which eventually leads to coronary heart disease (CHD), ischemic stroke and other atherosclerotic cardiovascular disease (ASCVD). Numerous studies have demonstrated an atherogenic role of oxidized low-density lipoprotein (ox-LDL) in the progression of ASCVD. This article briefly reviews the atherogenic mechanism of ox-LDL, the methods of measuring ox-LDL in the circulation, effect of medical therapy and life-style modification on ox-LDL level, and the association between circulating ox-LDL and atherosclerosis, including clinical ASCVD events and subclinical atherosclerosis, in observational studies.

Lectin-like oxidized low-density lipoprotein receptor-1:protein,ligands,expression and pathophvsiological significance

Objective To review the recent research progress in lectin-like oxidized low-density lipoprotein receptor-1 （LOX-1） including its protein, ligands, expression and pathophysiological significance. Data sources Information included in this article was identified by searching of PUBMED （1997-2006） online resources using the key term LOX-1. Study selection Mainly original milestone articles and critical reviews written by major pioneer investigators of the field were selected. Results The key issues related to the LOX-1 protein as well as ligands for LOX-1. Factors regulating the expression of LOX-1 were summarized. The pathophysiological functions of LOX-1 in several diseases were discussed. Conclusions Identification of LOX-1 and a definition of its biological role in pathophysiologic states provide deeper insight into the pathogenesis of some cardiovascular diseases especially in atherosclerosis and provide a potential selective therapeutic approach. LOX-1 is unlocking and drugs targeting LOX-1 might be a promising direction to explore.

Inhibitory Effects of Simvastatin on Oxidized Low-Density Lipoprotein-lnduced Endoplasmic Reticulum Stress and Apoptosis in Vascular Endothelial Cells

Background：Oxidized low-density lipoprotein （ox-LDL）-induced oxidative stress and endothelial apoptosis are essential for atherosclerosis. Our previous study has shown that ox-LDL-induced apoptosis is mediated by the protein kinase RNA-like endoplasmic reticulum kinase （PERK）/eukaryotic translation initiation factor 2α-subunit （eIF2α）/CCAAT/enhancer-binding protein homologous protein （CHOP） endoplasmic reticulum （ER） stress pathway in endothelial cells. Statins are cholesterol-lowering drugs that exert pleiotropic effects including suppression of oxidative stress. This study aimed to explore the roles of simvastatin on ox-LDL-induced ER stress and apoptosis in endothelial cells.Methods：Human umbilical vein endothelial cells （HUVECs） were treated with simvastatin （0.1, 0.5, or 2.5 μmol/L） or DEVD-CHO （selective inhibitor of caspase-3, 100 μmol/L） for 1 h before the addition of ox-LDL （100 μg/ml） and then incubated for 24 h, and untreated cells were used as a control group. Apoptosis, expression of PERK, phosphorylation of eIF2α, CHOP mRNA level, and caspase-3 activity were measured. Comparisons among multiple groups were performed with one-way analysis of variance （ANOVA） followed by post hoc pairwise comparisons using Tukey’s tests. A value of P 〈 0.05 was considered statistically significant.Results：Exposure of HUVECs to ox-LDL resulted in a significant increase in apoptosis （31.9% vs. 4.9%, P 〈 0.05）. Simvastatin （0.1, 0.5, and 2.5 μmol/L） led to a suppression of ox-LDL-induced apoptosis （28.0%, 24.7%, and 13.8%, F = 15.039, all P 〈 0.05, compared with control group）. Ox-LDL significantly increased the expression of PERK （499.5%, P 〈 0.05） and phosphorylation of eIF2α （451.6%, P 〈 0.05）, if both of which in the control groups were considered as 100%. Simvastatin treatment （0.1, 0.5, and 2.5 μmol/L） blunted ox-LDL-induced expression of PERK （407.8%, 339.1%, and 187.5%, F = 10.121, all P 〈 0.05, compared with control group） and phosphorylation of eIF2α （407.8%, 339.1%, 187.5%, F = 11.430, all P 〈 0.05, compared with control group）. In contrast, DEVD-CHO treatment had no significant effect on ox-LDL-induced expression of PERK （486.4%） and phosphorylation of eIF2α （418.8%）. Exposure of HUVECs to ox-LDL also markedly induced caspase-3 activity together with increased CHOP mRNA level; these effects were inhibited by simvastatin treatment.Conclusions：This study suggested that simvastatin could inhibit ox-LDL-induced ER stress and apoptosis in vascular endothelial cells.

Aqueous Extracts of Tribulus terrestris Protects Against Oxidized Low-Density Lipoprotein-Induced Endothelial Dysfunction

Objective： To investigate the role of aqueous extracts of Tribulus terrestris （TT） against oxidized low-density lipoprotein （ox-LDL）-induced human umbilical vein endothelial cells （HUVECs） dysfunction in vitro. Methods： HUVECs were pre-incubated for 60 min with TT （30 and 3 μg/mL respectively） or 105 mol/L valsartan （as positive controls） and then the injured endothelium model was established by applying 100 μg/mL ox-LDL for 24 h. Cell viability of HUVECs was observed by real-time cell electronic sensing assay and apoptosis rate by Annexin V/PI staining. The cell migration assay was performed with a transwell insert system. Cytoskeleton remodeling was observed by immunofluorescence assay. The content of endothelial nitric oxide synthase （eNOS） was measured by enzyme-linked immunosorbent assay. Intracellular reactive oxygen species （ROS） generation was assessed by immunofluorescence and flow cytometer. Key genes associated with the metabolism of ox-LDL were chosen for quantitative real-time polymerase chain reaction to explore the possible mechanism of TT against oxidized LDL-induced endothelial dysfunction. Results： TT suppressed ox-LDL-induced HUVEC proliferation and apoptosis rates significantly （41.1% and 43.5% after treatment for 3 and 38 h, respectively; P〈0.05）. It also prolonged the HUVEC survival time and postponed the cell＇s decaying stage （from the 69th h to over 100 h）. According to the immunofluorescence and transwell insert system assay, TT improved the endothelial cytoskeletal network, and vinculin expression and increased cell migration. Additionally, TT regulated of the synthesis of endothelial nitric oxide synthase and generation of intracellular reactive oxygen species （P〈0.05）. Both 30 and 3μg/mL TT demonstrated similar efficacy to valsartan. TT normalized the increased mRNA expression of PI3Kα and Socs3. It also decreased mRNA expression of Aktl, AMPKα, JAK2, LepR and STAT3 induced by ox-LDL. The most notable changes were JAK2, LepR, PI3Kα, Socs3 and STAT3. Conclusions： TT demonstrated potential lowering lipid benefits, anti-hypertension and endothelial protective effects. It also suggested that the JAK2/STAT3 and/or PI3K/AKT pathway might be a very important pathway which was involved in the pharmacological mechanism of TT as the vascular protective agent.

Protective Effect of Propyl Gallate Against Oxidized Low-Density Lipoprotein-Induced Injury of Endothelial Cells

Objective： To evaluate the protective effect of propyl gallate （PG）, an alkyl ester of gallic acid which is an active ingredient of Radix Paeoniae, against oxidized low-density lipoprotein （ox-LDL）-induced apoptosis and death in endothelial cells （ECs） and to find out its preliminary mechanism. Methods： The cultured endothelial cells were divided into normal, model （ox-LDL）, control （fetal bovine serum）, PG high dose （20 p,g/mL）, PG middle dose （10 μg/mL）, and PG low dose （5 μg/mL） groups, each derived from three different pools of umbilical cords. The model of injured human umbilical vein endothelial cells （HUVECs） was induced by ox-LDL. The 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl-2H-tetrazolium bromide （MTT） assay, Hoechst 33258 staining, flow cytometry and measurement of nitrogen monoxidum （NO） release were used to evaluate the protective effect of PG against ox-LDL-induced apoptosis and death in HUVECs. To find out the mechanism of this protective effect, the expression of endothelial nitric oxide synthase （eNOS） mRNA, eNOS protein expression, immunofluorescence of intracellular reactive oxygen species （ROS） and activities of malondialdehyde （MDA）, superoxidedismutase （SOD） and glutathione peroxidase （GPx） were observed. Results： PG significantly reduced ox-LDL-induced apoptosis and cell death. The percentage of cells death and apoptosis was significantly higher in the ox-LDL group than that in the control group （P〈0.05）. Compared with the control group, the cells death and apoptosis of PG group was no different （P〉0.05）. As compared with the ox-LDL group, results of the PG high dose group showed that cell viability was significantly increased （P〈0.05）, the level of NO release, expression of eNOS mRNA, densitometric value of eNOS protein expression, as well as the activities of SOD and GPx were all significantly higher （all P〈0.05）. Conclusion： PG could potentially serve as a novel endothelial protective agent against ox-LDL-induced injury of endothelial cell.

Peroxisome proliferator-activated receptor a agonist attenuates oxidized-low density lipoprotein induced immune maturation of human monocyte-derived dendritic cells

Accumulating evidence suggests that the Thl immune .response induced by various antigens such as oxidized low density lipoprotein （ox-LDL） and heat shock proteins （HSPs） play a key role in the process of atherosclerosis.1Dendritic cells （DCs） are the most potent antigen-presenting cells （APCs） in the body with the unique ability to initiate a primary immune response to certain antigens by the activation of ＂naive＂ T cells.2 The maturation of DC with the upregulation of costimulatory molecules such as CD83, CD40, CD86, and major histocompatibility complex （MHC） class molecules such as human leukocyte antigen （HLA）-DR, is required for DC to activate T cells. Pathologic studies have shown that immature DCs are present in normal arterial while abundant mature DCs clustered with T cells could be visualized in atherogenic vessels suggesting that DC 3 maturation is linked to the progression of atherosclerosls. Peroxisome proliferator-activated receptors （PPARs） a, one member of the family of PPARs, was found to have favorable effects on slowing the progression of atherosclerosis and reducing the risk of coronary heart disease in high-risk patients independent from their metabolism effects.4＇5 Furthermore, PPAR-α is also expressed on monocytes and monocyte-derived DCs.6 The effects of PPAR-α on DCs maturation and immune function remain unknown now, we therefore observed the effects of fenofibrate, a PPAR-α agonist, on the maturation and immune function of oxidized LDL-treated DCs in this study.