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Objective To observe the expressing changes of apolipoprotein M (ApoM),tumor necrosis factor-α(TNF-α) and monocyte chemoattractant protein-1 (MCP-1) in human retinal vascular endothelial cells (HRECs) under the high glucose culture condition and investigate the inhibitory effects of ApoM overepression on the expressions of TNF-α and MCP-1.Methods HRECs were cultured in DMEM containing 10％ fetal bovine serum and 5.5 mmol/L D-glucose and assigned to 6 groups.The cells in the normal control group were cultured in above culture medium;the cells in the high glucose group were treated using the DMEM with 30 mmol/L D-glucose;ApoM was transfected into the cells using lentiviral vector in the ApoM transfected group;lentiviral vector without ApoM sequence was transfected in the empty vector group;the cells transfected by empty vector were cultured in high glucose culture medium in the empty vector+high glucose group;the cells in the ApoM transfection+high glucose group were treated by ApoM sequence transfection and high glucose incubation.The relative expression of ApoM,TNF-α and MCP-1 mRNA was detected using real-time quantitative PCR,and the relative expression of ApoM protein was evaluated using Western blot assay.Results Compared with the normal control group,the mRNA expression levels of ApoM,TNF-α and MCP-1 in the high glucose group were significantly increased (t=5.517,3.295,2.555;all P＜0.05).HRECs grew well after infected with lentivirus.The relative expression level of ApoM mRNA in the ApoM transfected group was 236.400±39.270,which was significantly higher than 1.000±0.153 in the empty vector group (t=5.995,P＜0.01).An enhanced protein band of ApoM was seen in the ApoM transfected group,and the protein band was absent in the empty vector group.The relative expression band in the ApoM transfected group was 1.000± 0.249 and 2.978 ± 0.285 in the cells cultured with normal culture medium or high glucose culture medium,respectively,with a significant difference between them (t =5.056,P＜0.01).The relative expressions of TNF-α and MCP-1 in the mRNA levels were significantly different among the empty vector group,empty vector+high glucose group,ApoM transfected group and ApoM transfection + high glucose group (F =5.966,P =0.026;F =14.410,P =0.002).Compared with the empty vector+high glucose group,the relative expressions of TNF-α and MCP-1 mRNA were considerably reduced in the ApoM transfection+high glucose group (P=0.017,0.004).Conclusions High glucose environment up-regulates the expression of ApoM,MCP-1 and TNF-α in HRECs.Overexpression of ApoM inhibits the up-regulation of MCP-1 and TNF-α expression induced by high glucose.
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Objective To investigate the regulation and expression of VEGF gene in human umbilical vein endothelial cells under hypoxia and the influence of vascular activators,such as endothelin(ET),nitric oxide(NO)and NO synthesis inhibitor N-nitro-L-Arginie(L-NNA),on the expression of VEGF.Methods Culture the human umbilical vein endothelial cells and then treat by hypoxia and vascular activators.The expression on VEGF mRNA level and protein level were assayed by northern blots,ELISA and computer figure analysis system respectively.Results When human umbilical vein endothelial cells were subjected to hypoxia for 6 hours,the expression of VEGF began to increase.ET could increase the expression and NO inhibited it,and LNNA affected the expression of the VEGF.VEGF protein concentration in the cell culture media matches the mRNA result.They are 6 hours hypoxia (8
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We established a method to study vascular permeability in vitro on perfused endothelial cell monolayer cultured on micropore filter membrane. It can be used to determine filtration coefficient (Kf) and osmotic reflection coefficient (?) to proteins. Hanks balanced salt solution (HBSS) or 5 g/L albumin in HBSS was used to perfuse confluent endothelial monolayer. Control Kf values were 10.1 ?0.75 and 3.6?0.75?l . min-1 . cm-2 . kPa-1 (n = 3, x?sx) respectively for HBSS and albumin HBSS perfusion, suggesting that albumin may decrease endothelial monolayer permeability to water and small molecules. After exposure of endothelial monolayer to 10-8 mol/L platelet-activating factor (PAF) for 30 min, Kf values increased to 193.1% and 133.3% respectively for HBSS and albumin HBSS perfusion. Protein clearance rate (?l. min-1 . cm-2:) and osmotic reflection coefficient of control endothelial monolayer were 8.0?3.22 and 0. 37?0.09 respectively. In PAF treated endothelial monolayer,they were 12.2 ? 2.95ul min-1 cm 2 and 0.18?0.06, revealing increased permeability to albumin. Computer-assisted image processing demonstrated that PAF treatment decreased cell area while increased cell form factor and intercellular space. The results sug-gest that endothelial cells retracted, rounded and it may be an important mechanism in PAF-induced increased vascular permeability.
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The effects of hydrogen peroxide (H2O2) on endothelial-polymorphonuclear cells (EC-PMN) adhesion and their mechanisms wsre studied in cultured bovine pulmonary artery endothelial monolayers in vitro. H2O2 at various concentrations (10-1, 10-2, 10-3mol/L respectively) stimulated EC dependent PMN adhesion, of which l02mol/L H2O2 was the most potent one, increasing adhesion to 2.3 times that of the control. Pretreatment of PMNs with SRI 63-441, a platelet-activating factor (PAF) receptor antagonist, had no effect on H2O2 induced EC-PMN adhesion. Pretreatment of ECs with SRI 63-441 before H2O2 exposure significantly decreased PMN adherence to ECs. Pretreatment of ECs with phospholipase A2 inhibitor p-bromophenacyl-bromide or cahnodulin antagonist chlorpromazine and aildum ion chelate EGTA obviously decreased H2O2 induced increment of EC-PMN adhesion. These results suggest that H2O2 may activate ECs, causing the inflow of extracellular calcium or the release of calcium from intracellular deposits. Increased intracellular Ca2+ may bind with calmodulin to activate phospholipase A2 thus initiating PAF synthesis and promoting EC-PMN adhesion.