Effect of water extract propolis on expression of vascular endothelial cell adhesion molecules

AIM: To explore the mechanism of propolis on the inhibition of atherosclerosis and thrombosis in injured human umbilical vascular endothelial cells (HUVECs) induced by tumor necrosis factor alpha (TNF-α)in vitro.METHODS: TNF-α at the concentration of 50 μg/L was used to induce the injury of HUVECs. The injured HUVECs were treated with water extract propolis (WEP) at the concentrations of 50, 100 and 200 mg/L for 6 h, 12 h and 24 h. The expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was examined by flow cytometry.RESULTS: The expression of ICAM-1 and VCAM-1 was significantly higher in injured HUVECs (P<0.01) than that in the control cells. The expression of ICAM-1 and VCAM-1 was downregulated by WEP treatment in a dose-dependent manner. Between the groups of 100 and 200 mg/L WEP, the difference was significant. In the injured HUVECs treated with 50 mg/L WEP, the inhibitory effect on the expression of ICAM-1 and VCAM-1 was presented in a time-dependent manner. Compared to the single administration, the use of WEP combined with fluvastatin showed better inhibitory effect on the expression of ICAM-1 and VCAM-1 in the injured HUVECs induced by TNF-α (P<0.01).CONCLUSION: WEP may be helpful for the protection of vascular endothelial cells by inhibiting the expression of ICAM-1 and VCAM-1 in a time-and dose-dependent manner. The protective effect of WEP on endothelial cells may be synergic with the inhibitor of HMG-CoA reductase such as fluvastatin sodium.     

Effect of oxidized LDL on expression of connexin43 in cultured human umbilical vein endothelial cells

AIM: To investigate the effect of oxidized LDL (ox-LDL) on the expression of gap junction protein connexin43 in cultured human umbilical vein endothelial cells (HUVECs) in vitro. METHODS: Human umbilical vein endothelial cells cultured in normal condition were divided into blank control group, 50 mg/L,100 mg/L and 200 mg/L ox-LDL intervention groups. The mRNA expression of connexin43 in cultured HUVECs was detected with RT-PCR method; while the protein level of connexin43 was determined by the method of immunocytochemistry in the control and 100 mg/L ox-LDL intervention groups 24 h after ox-LDL was given. RESULTS: Different concentrations (50 mg/L, 100 mg/L, 200 mg/L) of ox-LDL up-regulated mRNA expression of connexin43 in cultured HUVECs after 24 h intervention (P<0.01). The protein level of connexin43 in cultured HUVECs intervened with 100 mg/L Ox-LDL for 24 h was up-regulated as compared to the control cells (P<0.01).CONCLUSION: Ox-LDL may up-regulate the expression of connexin43 at mRNA and protein levels in cultured human umbilical vein endothelial cells within short time, indicating that connexin43 plays an important role in the pro-atherosclerotic effect of Ox-LDL.     

Protective effect of diphenyleneiodonium,a NADPH oxidase inhibitor,on hyperpermeability of endothelial cells exposed to AOPP-HSA in vitro

AIM: To investigate the effect of advanced oxidation protein product-human serum albumin (AOPP-HSA) at different concentrations on the permeability of human umbilical vein endothelial cell (HUVEC) monolayer and the protective effect of NADPH oxidase inhibitor diphenyleneiodonium (DPI) against AOPP-HSA exposure. METHODS: Cultured HUVECs were exposed to 200 mg/L HSA (control) or AOPP-HSA (50, 100 and 200 mg/L). The permeability of the endothelial monolayer was assessed by measuring CMFDA-labeled THP-1 cells across the endothelial cells. The cultured HUVECs were treated with HSA (200 mg/L), AOPP-HSA (200 mg/L), or AOPP-HSA (200 mg/L) + DPI (100 μmol/L), and the activation of NADPH oxidase, endothelial monolayer permeability and cytoskeleton rearrangement were evaluated. RESULTS: AOPP-HSA increased the permeability of the endothelial cell monolayer, and AOPP-HSA at 200 mg/L significantly increased the phosphorylation level of NADPH oxidase in the cells. Treatment with 100 μmol/L DPI obviously attenuated AOPP-HSA-induced NADPH oxidase activation, the increase in the permeability of the cell monolayer and the cytoskeleton rearrangement. CONCLUSION: AOPP-HSA increases the hyperpermeability of HUVEC monolayer via the phosphorylation of NADPH oxidase, and the NADPH oxidase inhibitor DPI reverses such effects.     

Tumor necrosis factor-related apoptosis-inducing ligand participates in injury of vascular endothelial cells induced by rapamycin in vitro

AIM: To investigate the effects of rapamycin on apoptosis, proliferation, migration ability and tumor related apoptosis inducing ligand(TRAIL) in cultured human umbilical vein endothelial cells(HUVECs). METHODS: Cultured HUVECs were treated with rapamycin at the concentrations of 0, 1, 10 and 100 μg/L for 24 h. The cell proliferation was measured by CCK-8 method. The cell migration ability was detected by Transwell chambers and wound healing test. The apoptotic index of HUVECs was quantitatively determined by measuring the activation of caspase-3. The morphological changes of the apoptotic cells were observed by DAPI staining. The expression of TRAIL was detected by Western blotting. RESULTS: A 24 h-incubation with rapamycin(1-100 μg/L) caused significant cell loss associated with the increase in apoptosis, as quantified by the determination of caspase-3 activity(P<0.01) in HUVECs. Obvious apoptotic morphology was observed by DAPI staining in HUVECs incubated with rapamycin. Rapamycin at the concentrations of 1-100 μg/L also impaired the migration ability of HUVECs(P<0.01). In addition, rapamycin(10-100 μg/L) inhibited the proliferation of HUVECs, whereas rapamycin at 1 μg/L had no such effect(P<0.01). Rapamycin(10-100 μg/L) also induced TRAIL expression in a dose-dependent manner(P<0.01). CONCLUSION: Rapamycin induces apoptosis, and inhibits the proliferation and migration of HUVECs. The up-regulation of TRAIL might be related to the injury of vascular endothelial cells caused by rapamycin.     

Effects of advanced glycation end products on protein and mRNA expression of macrophage inflammatory protein-1α in cultured human umbilical vein endothelial cells

AIM: To investigate the effects of advanced glycation end products (AGEs) on protein and mRNA expression of macrophage inflammatory protein-1α (MIP-1α) in cultured human umbilical vein endothelial cells(HUVECs). METHODS: HUVECs were cultured with AGEs at different concentrations for 24 h and at a concentration of 400 mg/L for different time.The levels of mRNA and protein expression of MIP-1α in cultured HUVEC were detected by in situ hybridization and Western blot, respectively. RESULTS: In situ hybridization showed that after exposure of HUVECs to AGEs at different concentrations (100 mg/L, 200 mg/L, 400 mg/L) for 24 h, the average integrated optical density values (18.76±3.17, 26.58±1.61, 34.23±2.25) of MIP-1α mRNA expression in HUVECs were higher than that in control group (13.83±1.24, P0.05). After exposure of HUVECs to AGEs at a concentration of 400 mg/L for 12 h, 24 h and 36 h, the average integrated optical density values of MIP-1α mRNA expression in HUVECs were 22.67±1.46, 34.23±2.25 and 42.28±3.14, higher than that in 0 h group (12.56±1.24, P0.05). Western Blot showed that exposure of HUVECs to AGEs at different concentrations(100 mg/L, 200 mg/L, 400 mg/L) for 24 h resulted in a 1.34-fold, 1.87-fold and 2.46-fold increase in the expression of MIP-1α protein in HUVECs compared with BSA control group (P<0.05). Meanwhile, exposure of HUVECs to AGEs at a concentration of 400 mg/L for 12 h, 24 h and 36 h resulted in a 1.82-fold, 2.71-fold and 3.34-fold increase in MIP-1α protein expression in HUVECs compared with 0 h group (P<0.05). CONCLUSION:These data suggest that AGEs could induce a high expression of MIP-1αmRNA and protein in cultured HUVECs in a dose-dependent and time-dependent manner.     

Effect of TNF-α on the cartilage endplate chondrocytes of New Zealand white rabbits

AIM:To evaluate the biological roles of TNF-α on the cartilage endplate cells (chondrocytes). METHODS:The chondrocytes were isolated and harvested from the cartilage endplate of New Zealand rabbits and then the biological characteristics of cells were identified by methods such as toluidine blue staining for type Ⅱ collagen. After different concentrations of TNF-α were added to culture medium respectively, the rate of the proliferation of chondrocytes in different time was measured with MTT. The protein expressions of Bax, Bcl-2, Fas and caspase-3 were measured by immunocytochemistry. The changes of the mRNA of aggrecan and type Ⅱ collagen were measured by RT-PCR. RESULTS:The TNF-α at concentration of 50 μg/L and 100 μg/L decreased the rate of the proliferation on chondrocytes. Though TNF-α at concentrations of 10 μg/L and 50 μg/L increased the level of Bax, Fas and caspase-3, only 50 μg/L TNF-α decreased the level of Bcl-2. TNF-α at concentrations of 10 μg/L and 50 μg/L decreased the level of collagen IIa mRNA and only 50 μg/L TNF-α decreased the level of aggrecan. CONCLUSION:TNF-α not only inhibits the proliferation and the matrix synthesis in chondrocytes, but also increases the expression of pro-apoptotic factors in chondrocytes.     

Dual-direction effect of crenulatin on apoptosis of cerebral microvascular endothelial cells and it's mechanism

) ［ABSTRACT］AIM: To study the effect and the mechanism of crenulatin, an effective constituent of Chinese traditional medicine, on apoptosis of cerebral microvascular endothelial cells. METHODS: The following terminal concentrations of crenulatin were used in the study: 25 mg/L and 100 mg/L. Apoptosis of mouse cerebral microvascular endothelial cells (bEnd.3 cell line) was evaluated by flow cytometer, immunocytochemical assay (Fas, Bcl-2) and Western blotting (caspase-3) after culture for 24 h. RESULTS: Compared with control group, apoptosis of bEnd.3 cells in 25 mg/L group was significantly inhibited (P<0.05), but apoptosis in the 100 mg/L group was significantly increased (P<0.05). In apoptosis inhibited group, the Fas immunocytochemical staining was weaker, the positive cells were significantly decreased (P<0.05) and caspase-3 expression was decreased compared with control group; however, the Bcl-2 staining was stronger and the positive cells were significantly increased (P<0.05). On the other hand, in apoptosis increased group (100 mg/L group), the changes were just opposite. CONCLUSIONS: The effect of crenulatin on apoptosis of mouse cerebral microvascular endothelial cells possesses a dual-direction change, inhibitive effect in 25 mg/L and stimulative effect in 100 mg/L group, respectively. The mechanism is related to the alterations of Fas/Bcl-2 expression and caspase-3 activity.     

Tongxinluo improves anti-hypoxia ability of vascular endothelial cells via PI-3K/Akt/HIF pathway

AIM: To investigate the effects of PI-3K/Akt/HIF pathway on anti-hypoxia ability of vascular endothelial cells influenced by Tongxinluo under hypoxic condition. METHODS: Human umbilical vein endothelial cells (HUVECs) were divided into the following groups: control group, Tongxinluo (100 mg/L) group, hypoxia group and hypoxia+Tongxinluo (100 mg/L) group. The CCK-8 assay were used to detect the viability and proliferation rate of the cells in each group. The protein levels of HIF-1α, Bcl-2, Mcl-1, Bax and phosphorylated Akt were studied by immunoblotting analysis. The HUVECs were transiently transfected with the dominant negative mutant of HIF-1α (DN-HIF). The apoptotic rates were analyzed by flow cytometry (FCM). The HUVECs were transiently transfected with the dominant negative mutant of PI-3K (Δp85) or Akt (DN-Akt) to investigate the role of PI-3K/Akt signal pathway in the anti-hypoxia ability of Tongxinluo on endothelial cells. RESULTS: Under hypoxic condition, although the proliferation rate increased significantly in Tongxinluo group compared with hypoxia group, the degree was notably weak compared with control group. The protein levels of HIF-1α, Bcl-2, Mcl-1 and phosphorylated Akt were up-regulated by Tongxinluo. Meanwhile, the expression of Bax was down-regulated. Inhibition of HIF-1α activation by DN-HIF and inhibition of the PI-3K/Akt pathway by Δp85 or DN-Akt attenuated the increase in HIF-1α expression and HUVEC viability induced by Tongxinluo. The percentage of apoptotic HUVECs was down-regulated to a certain extent by Tongxinluo. CONCLUSION: Tongxinluo improves the anti-hypoxia ability of vascular endothelial cells by up-regulating the protein level of HIF-1α, promoting the expression of anti-apoptotic factors, improving the cell viability and eventually reducing the apoptotic rate.These effects of Tongxinluo depend on PI-3K/Akt signal pathway.     

Effect of activated protein C on apoptosis in human umbilical vein endothelial cells induced by lipopolysaccharide

AIM:To study the effect of activated protein C (APC) at different concentrations on apoptosis of human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS).METHODS:The HUVECs were induced by LPS (1.0 mg/L) as apoptotic model that was administered by different concentration of APC (10 μg/L or 50 μg/L). Meanwhile, the control group and induced apoptosis group induced by LPS (1.0 mg/L) stimulation were also set up. The changes of cellular ultrastructures were observed under electron microscope. The DNA ladder and TUNEL fluorescent staining were measured in cells. Annexin-Ⅴ/PI double staining was used to measure the cell apoptosis rate by flow cytometry. Cell survival rate was measured by MTT assay. The proliferating cell nuclear antigen (PCNA) expression levels in cells were also measured by Western blotting to reflect the proliferation of the cells.RESULTS:There were significant apoptotic changes in the cells induced by LPS, but the apoptotic changes were reduced and apoptosis rates were decreased in the cells treated with APC. Meanwhile, cell survival rate and the protein levels of PCNA were increased after APC treatment, particularly at the concentration of 50 μg/L, which showed difference when compared with those induced apoptosis group by LPS (P<0.05).CONCLUSION:APC can inhibit HUVECs apoptosis induced by LPS and promote cell proliferation, thus protect the cells from injury.     

Sinomenine inhibits TNF-α-induced VCAM-1 expression on human umbilical vein endothelial cells

AIM: To investigate whether sinomenine(SN) can decrease TNF-α-induced VCAM-1 expression in human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were isolated from freshly collected umbilical cords.Positive control samples were stimulated with TNF-α, omitting SN. Negative control samples were treated in the same way, omitting TNF-α and SN. Experiment samples were co-cultured with TNF-α and SN at different concentration (0.25, 0.5, and 1.0 mol/L),or TNF-α and dexamethasone(Dex) at concentration of 1.0×10^-6mol/L.Cells were harvested after cultivation with the drugs for 12 hours. VCAM-1 mRNA expression was detected by real-time quantitative PCR, and VCAM-1 expression was detected by flow cytometry (FCM).RESULTS: VCAM-1 mRNA and VCAM-1 were induced by TNF-α. Compared with the positives, the relative VCAM-1 mRNA expression decreased to varying degrees in the experiment groups (P<0.05), and SN at concentration of 0.5 mol/L and 1.0 mol/L inhibited expression of VCAM-1 (P<0.05). SN at concentration of 1.0 mol/L decreased VCAM-1 expression by 28.8%(P<0.05), and SN at concentration of 0.5 mol/L reduced VCAM-1 expression by 21.68%(P<0.05). But SN at concentration of 0.25 mol/L and Dex at concentration of 1.0×10^-6mol/L didnt depress expression of VCAM-1. CONCLUSION: SN may inhibit TNF-α-induced VCAM-1 expression in HUVECs in vitro.     

Effects of oxygen free radicals and captopril on endogenous NOS inhibitor in human vascular endothelial cells

AIM: To observe the effects of oxygen free radical (OFR) and captopril on the level of asymmetric NG, NG-dimethyl-L-arginine (ADMA) in human vascular endothelial cells (HUVECs).METHODS: HUVECs of 3-6 th passage, cultured with modified Jaffes’ method, were used in the experiment and divided into three groups: (1)Cells cultured with equivalence of DMEM medium as control; (2)OFR intervention groups, OFR at concentrations of 0.01 mmol/L, or 0.1 mmol/L, respectively, were added to the cell culture; (3)Drug intervention groups: the cell culture was treated with 0.1 mmol/L of OFR combined with 50 mg/L or 100 mg/L of captopril, respectively. Concentrations of ADMA, L-arginine, nitric oxide(NO), endothelin(ET) and the activity of angiotensin-converting enzyme(ACE) in conditioned medium were measured after 24 h exposure. RESULTS: Concentrations of ADMA, ET and the activity of ACE were increased, while the amount of NO decreased in OFR intervention groups compared with control group. After treatment with captopril, ADMA, ET concentrations and the activity of ACE were decreased, while the amount of NO increased, but the level of L-arginine had no obvious change. CONCLUSIONS: OFR induces endothelial dysfunction through increasing ADMA concentration, while captopril relieves endothelial dysfunction induced by ox-LDL through decreasing ADMA concentration.     

Effect of lipopolysaccharide on apoptosis of human umbilical vein endothelial cells

AIM: To explore the mechanism of lipopolysaccharide (LPS) on vascular endothelial cell(VEC) damage. METHODS: By using cytometry techniques, we studied the effects of LPS on apoptosis of human umbilical vein endothelial cells (HUVECs) in vitro. RESULTS: LPS was able to induce apoptosis of HUVECs in a time-dose-dependent fashion.CONCLUSION:Apoptosis might play a role in LPS-induced damage of vascular endothelial cells.     

Naringin protects human umbilical vein endothelial cells against injury induced by high glucose through PI3K/AKT/eNOS pathway

AIM: To investigate the protective effect of naringin (Nar) on the injury of human umbilical vein endothelial cells (HUVECs) induced by 33 mmol/L high glucose (HG) and to explore its possible mechanisms.METHODS: The injury model was established by treating HUVECs with HG medium for the indicated time (6, 12, 24, 48 and 72 h), and then the levels of NO, eNOS and p-eNOS were detected, respectively. The effects of Nar on high glucose-induced endothelial cell injury were observed. HUVECs were treated with Nar at concentrations of 5, 10, 25, 50 and 100 mg/L for 6 h, 12 h, 24 h, 36 h and 48 h. The levels of NO in the supernatants were measured. The effects of Nar on HG-injured HUVECs were explored by treating the cells with 10 μmol/L of LY294002, a PI3K inhibitor, or 0.5 μmol/L of AKT inhibitor Ⅳ, an AKT inhibitor, and then the levels of NO, PI3K, AKT, eNOS and their phosphorylated proteins were determined by Western blot.RESULTS: Nar at concentration of 50 mg/L significantly attenuated the injury of endothelial cells induced by high glucose (P<0.01), and the protective effects of Nar were abolished by pretreating with the inhibitor of PI3K or AKT (P<0.01).CONCLUSION: Nar protects endothelial cells against the injury induced by high glucose through PI3K/AKT/eNOS pathway.     

Effects of simvastatin on cigarette smoke extract-induced sEPCR and EPCR expression in human umbilical vein endothelial cells

AIM: To investigate the effects of simvastatin on cigarette smoke extract (CSE)-induced expression levels of soluble endothelial cell protein C receptor (sEPCR) and membrane-associated endothelial cell protein C receptor (mEPCR ) in human umbilical vein endothelial cells (HUVECs). METHODS: Cultured HUVECs at passage 4 to 6 were randomly divided into control group, 5% CSE group, simvastatin groups and simvastatin+CSE groups. In simvastatin groups, HUVECs were incubated with simvastatin at the concentrations of 50, 100 and 200 μmol/L for 24 h. In simvastatin+CSE groups, the cells were treated with simvastatin at the concentrations of 50, 100 and 200 μmol/L for 2 h, and then exposed to CSE for 24 h. The protein level of sEPCR in the culture supernatants was measured by ELISA. The cells were collected for determining the mRNA expression of mEPCR by real-time PCR. RESULTS: Compared with control group, the protein level of sEPCR was significantly increased, and the mRNA expression of mEPCR was significantly decreased in 5% CSE group (both P<0.05). The protein levels of sEPCR were significantly increased, and the mRNA expression of mEPCR was significantly decreased in 100 μmol/L and 200 μmol/L simvastatin groups. However, the protein levels of sEPCR were lower, and the mRNA expression of mEPCR was significantly higher in 100 μmol/L and 200 μmol/L simvastatin groups than those in 5% CSE group. Compared with 5% CSE group, the protein levels of sEPCR in simvastatin+CSE groups were significantly decreased, but higher than those in control group and simvastatin group with corresponding concentration. On the contrary, the mRNA expression of mEPCR in simvastatin+CSE groups was significantly increased, but lower than that in control group and simvastatin group with corresponding concentration (all P<0.05). CONCLUSION: Simvastatin obviously increases the mRNA expression of mEPCR, decreases the protein level of sEPCR, and attenuates the CSE-induced endothelial injury in vitro .     

Ethanol extract of propolis protects vascular endothelial cells from oxidized low-density lipoprotein-induced apoptosis by inhibiting C/EBP homologous protein expression

AIM: To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-density lipoprotein (ox-LDL)-induced vascular endothelial cell apoptosis and the underlying molecular mechanisms.METHODS: Human umbilical vein endothelial cells (HUVECs) were pretreated with EEP (7.5, 15 and 30 mg/L) or 4-phenylbutyric acid (PBA, 4 mmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin (TM, 4 mg/L) for 24 h. The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC/PI double staining, respectively. The activities of lactic dehydrogenase (LDH) in the medium and caspase-3 in the HUVECs were measured. The protein and mRNA levels of C/EBP homologous protein (CHOP), a proapoptotic molecule under endoplasmic reticulum stress (ERS), and its downstream Bcl-2 were examined by Western blot and real-time PCR, respectively.RESULTS: Like PBA (an ERS inhibitor), EEP protected HUVECs from ox-LDL-induced injury in a dose-dependent manner, as assessed by the increased cell viability and the decreased LDH release, apoptotic rate and caspase-3 activation. The decrease in cell viabi-lity and the increases in LDH release, apoptotic rate and caspase-3 activation induced by TM, an ERS inducer, were also attenuated by EEP. Moreover, EEP suppressed ox-LDL-induced CHOP upregulation and Bcl-2 downregulation, and this effect was similar to that of PBA. Similarly, EEP significantly suppressed TM-induced CHOP upregulation both at the protein and mRNA levels.CONCLUSION: EEP may protect HUVECs from ox-LDL-induced apoptosis, and the mechanism is at least partially involved in suppressing CHOP-mediated ERS-associated apoptotic pathway.     

中国园艺学会第七届青年学术讨论会

中国园艺学会第九届第8次常务理事扩大会决定,“中国园艺学会第七届青年学术讨论会”由山东农业大学园艺科学与工程学院和山东省园艺学会承办,将于2006年7月或8月在山东泰安举行。会议交流主题:(1)园艺作物种质资源、遗传育种与生物技术;(2)园艺作物有机、无公害及标准化安全生     

2,3,5,4’-Tetrahydroxystilbene-2-O-β-D-glucoside protects against LPC-induced endothelial cell injury

AIM: To observe the protective effect of 2,3,5,4’-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) on lysophosphatidylcholine (LPC)-induced vascular endothelial cell injury. METHODS: The 3rd and 4th generations of human umbilical vein endothelial cells (HUVECs) were cultured in vitro and propagated. The cells were randomly divided into 3 groups: control group, model group (LPC) and experimental group (TSG+LPC). The cells in control group were not treated with any reagent. To establish endothelial cell injury model, LPC was administered to HUVECs at concentration of 10 mg/L and incubated with the cells for 24 h. In TSG+LPC group, TSG was administered to HUVECs at concentrations of 10.0, 1.0 and 0.1 μmol/L 1 h before administration of LPC, and then the cells were incubated for 24 h. The cell viability, the content of asymmetric dimethyl arginine (ADMA) and NO, and apoptotic rate were detected. RESULTS: Compared with control group, ADMA content in the cell culture supernatants and apoptotic rate of the HUVECs in LPC group were significantly increased, while the NO content and cell viability were notably decreased. Compared with LPC group, ADMA content and apoptotic rate in TSG+LPC group was significantly decreased, while the NO content and cell viability were notably increased. CONCLUSION: TSG may protect LPC-injured vascular endothelial cells by attenuating the expression of ADMA and enhancing the production of NO, thus inhibiting apoptosis and increasing cell survival rate.     

Proliferation and apoptosis of human umbilical vein endothelial cells induced by oxidized low density lipoprotein

AIM:To investigate proliferation and apoptosis of cultured endothelial cell (ECV-304 cell line) induced by varied concentrations of oxidized low density lipoprotein (ox-LDL). METHODS:Cell morphology, Typan blue test, MTT test, LDH release test, flow cytometry and micro-molecular weight DNA fragment gel electrophoresis of apoptosis were used for the detection of the cytotoxic effects of ox-LDL on ECV-304 cell line.RESULTS:0.1, 1, 10 mg/L ox-LDL could promote proliferation of ECV-304 cells. When the concentration of ox-LDL reached up to 100 mg/L and above, the distinct cytotoxic effect appeared. Further study showed that the apoptosis rate of endothelial cells, induced by ox-LDL of 150 mg/L and 200 mg/L for 12 hours, are 15.86% and 21.89%, respectively. 18 h and above hours after incubation, the apoptosis rate began to decrease and rate of necrosis increased. CONCLUSION:ox-LDL has strong cytotoxic effects on endothelial cells and could give rise to different pathologic process, such as proliferation, apoptosis prophase, apoptosis and necrosis.     

Effects of GW1929 on macrophage TLR expression and inflammation induced by ox-LDL

AIM: To investigate the effects of ox-LDL on TLR2 and TLR4 expression and production of TNF-α, IL-10, IL-12, NO and MDA in macrophages and to observe intervention effect of GW1929 in above procedure. METHODS: The mouse peritoneal macrophages were pretreated with ox-LDL (50 mg/L, 100 mg/L) and GW1929 (20 μmol/L) respectively for 24 h. The concentrations of MDA, NO-2/NO-3, TNF-α, IL-10 and IL-12 in the culture fluid were detected. Flow cytometry was used to observe TLR2 and TLR4 expressions after the mouse peritoneal macrophages were pretreated with ox-LDL (50 mg/L) and GW1929 (20 μmol/L) respectively for 6 h, 12 h, and 24 h. RESULTS: The concentrations of MDA, NO-2/NO-3, TNF-α and IL-10 in ox-LDL (50 mg/L, 100 mg/L) group were higher than those in control and GW1929 group obviously, but the concentrations of above index in ox-LDL (50 mg/L, 100 mg/L)+GW1929 group were lower than those in ox-LDL (50 mg/L, 100 mg/L) group apparently. No IL-12 in every group was detected. Expressions of TLR-2 in ox-LDL+GW1929 (6 h, 12 h, 24 h) group were lower than those in ox-LDL (6 h, 12 h, 24 h) group respectively. TLR-4 expressions in ox-LDL+GW1929 (12 h) were lower than those in ox-LDL (12 h) apparently. CONCLUSION: ox-LDL up-regulates TLR2 and TLR4 expressions and promotes the production of ROX, NO, TNF-α and IL-10 in macrophages. GW1929 is capable of inhibiting the above ox-LDL effects.