Effect of curcumin on ox-LDL-induced HAEC injury

AIM: To investigate the effect of curcumin on oxidized low-density lipoprotein (ox-LDL)-induced injury of human aortic endothelial cells (HAECs). METHODS: HAECs were pre-treated with curcumin at different concentrations and then treated with ox-LDL. The cell viability was assessed by MTT assay. The cell proliferation ability was analyzed by EdU assay. ELISA was used to determine the concentrations of interleukin-6 (IL-6), transforming growth factor β1 (TGFβ1), high mobility group box-1 protein (HMGB1) and secretory receptor for advanced glycation end products (sRAGE) in the HAEC culture medium. The binding activity of peroxisome proliferator-activated receptor γ (PPARγ) was evaluated by electrophoretic mobility shift assay. The protein levels of HO-1, HMGB1, RAGE,IL-6,TGFβ1 and phosphorylated PPARγ in the HAECs were determined by Western blot. RESULTS: The viability and the proliferation ability decreased significantly in the HAECs treated with ox-LDL. The PPARγ/HO-1 signaling pathway was inhibited while its down-stream HMGB1/RAGE signaling pathway was activated by ox-LDL. The levels of IL-6, TGFβ1, HMGB1 and sRAGE were increased. Pre-treatment with curcumin activated PPARγ/HO-1 signaling pathway and inhibited HMGB1/RAGE signaling pathway in ox-LDL treated HAECs in a concentration-dependent manner. The levels of IL-6, TGFβ1, HMGB1 and sRAGE were also decreased dramatically by pre-treatment of curcumin in a concentration-dependent manner. CONCLUSION: ox-LDL induces HAEC damage by inhibiting PPARγ/HO-1 to activate HMGB1/RAGE inflammatory signaling. Curcumin exerts protective effect on ox-LDL treated HAECs via activating PPARγ/HO-1 signaling pathway.     

Role of receptors for oxidized low-density lipoprotein in pathogenesis of atherosclerosis

The formation of atherosclerosis （AS） is an evolutionary process. It undergoes lipid deposition, focal fibrosis in the intima of the arteries and atherosclerotic plaque formation, resulting in hardening of the vessel wall and stenosis of the lumen, which eventually leads to ischemic changes in the corresponding organs. In these processes, oxidized low-density lipoprotein （oxLDL）, an oxidative product of low-density lipoprotein, is considered to be a key trigger for AS development. In this paper, the role of the receptors for oxLDL in the development of AS is reviewed based on the recent studies.     

Ethanol extract of propolis protects macrophages from oxidized low-density lipoprotein-induced apoptosis by inhibiting caspase-12

AIM: To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-density lipoprotein (ox-LDL)-induced macrophage apoptosis and the underlying molecular mechanisms. METHODS: RAW264.7 macrophages were pretreated with EEP (7.5, 15 and 30 mg/L), 4-phenylbutyric acid (PBA, 5 mmol/L) or diphenyleneiodonium (DPI, 5 μmol/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 apoptosis detection kit, respectively. The activity of superoxide dismutase (SOD), and the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in the cells were measured. The protein levels of caspase-12, a proapoptotic molecule under endoplasmic reticulum stress (ERS), were examined by Western blot analysis. RESULTS: Like PBA (an ERS inhibitor), EEP protected RAW264.7 macrophages from ox-LDL-induced injury in a dose-dependent manner, as assessed by the increased cell viability and the decreased apoptotic rate. The decrease in cell viability and increase in apoptotic rate induced by TM, an ERS inducer, were also attenuated by EEP. Moreover, EEP suppressed ox-LDL-induced oxidative stress as revealed by the decreased generation of ROS and MDA as well as elevated SOD activity, which were similar to DPI, an oxidative stress inhibitor. Furthermore, EEP significantly suppressed ox-LDL- or TM-induced activation of caspase-12. Similar results were observed in the cells pretreated with PBA or DPI and then treated with ox-LDL. CONCLUSION: EEP may protect RAW264.7 macrophages from ox-LDL-induced apoptosis and the mechanism is at least partially involved in the ability of EEP to suppress oxidative stress and subsequent activation of caspase-12.     

Protective effect of quercetin on ER stress-related apoptosis induced by thapsigargin in macrophages

AIM: To investigate the effects and possible mechanisms of quercetin (Que) on endoplasmic reti-culum stress (ERS)-related apoptosis induced by thapsigargin (TG) in RAW264.7 cells. METHODS: ER stress of RAW264.7 cells were induced by TG at concentration of 1 μmol/L for 24 h. After treated with different concentrations of Que (80, 120 and 160 μmol/L), the cell viability was determined by MTT assay.The apoptotic rate and the changes of intracellular Ca²⁺ concentration ([Ca²⁺]_i) were determined by flow cytometry, and the cell apoptotic morphology was observed under laser scanning confocal microscope.The protein levels of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) were detected by Western blotting. The effect of Que on GRP78 and CHOP induced by TG with phosphatidylinositol 3-kinase (PI3K) inihibitor LY294002 at concentration of 15 nmol/L was measured by Western blotting. RESULTS: Que suppressed ER stress-related injury induced by TG in RAW264.7 cells. Compared with TG group, the cell viability increased (P<0.05), apoptotic rate and [Ca²⁺]_i decreased (P<0.05) and the changes of apoptotic morphology were alleviated. The increase in GRP78 and CHOP induced by TG as an ER stress marker was suppressed by Que (P<0.05). The suppressive effect of Que on GRP78 and CHOP was reproduced by LY294002 (P<0.05), but they failed to exhibit additive suppression. CONCLUSION: Que suppresses the ER stress induced by TG in RAW264.7 cells. The protective effect may be related to its suppression on PI3K signaling pathway.     

Role of PI3K/Akt/eNOS signaling pathway in inhibitory effects of puerarin on ox-LDL-induced TF expression in vascular endothelial cells

AIM:To explore the role of phosphatidylinositiol 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling pathways in the inhibitory effects of puerarin on oxidized low-density lipoprotein (ox-LDL)-induced tissue factor (TF) expression in vascular endothelial cells.METHODS:The mRNA expression of TF was detected by real-time fluorescent quantitative PCR.The protein levels of TF and Akt was determined by Western blot.The content of the nitric oxide (NO) was measured by nitrate reduction method.RESULTS:Compared with control group,incubating endothelial cells with ox-LDL significantly induced TF expression at mRNA and protein levels and the dephosphorylation of Akt protein,and decreased NO production.Incubation of the endothelial cells with puerarin for 1 h and then treatment of the cells with ox-LDL decreased the TF expression at mRNA and protein levels,increased Akt protein phosphorylation and intracellular NO content.Co-incubation of the endothelial cells with PI3K inhibitor LY294002 and puerarin for 1 h and then treatment of the cells with ox-LDL augmented the TF expression at mRNA and protein levels and the Akt protein dephosphorylation,and decreased NO production.Co-incubation of the endothelial cells with eNOS inhibitor N^G-nitro-L-arginine methyl ester (L-NAME) and puerarin significantly decreased the inhibitory effect of puerarin on ox-LDL-induced TF expression at mRNA and protein levels in the endothelial cells,and reduced Akt protein phosphorylation and NO production.CONCLUSION:Puerarin inhibits ox-LDL-induced TF expression at mRNA and protein levels in the human umbilical vein endothelial cells via activation of PI3K/Akt/eNOS signaling pathway.     

The role of chlamydia pneumoniae in the course of transformation of C57 BL/6J mouse peritoneal macrophages into foam cells

AIM: In order to understand the role of chlamydia pneumoniae in the course of macrophages transformation into foam cells experiments with chlamydia pneumoniae standard strain AR-39 wese made. METHOD: C57 BL/6J Mouse peritoneal macrophages C57 BL/6J wese incubated 24 h, and they were divided into 6 groups to be incubated continually: A₁~DMEM; A₂~DMEM+10 IFUs/L AR-39; B₁~DMEM+10mg/L LDL; B₂~DMEM+10mg/L LDL+10 IFUs/L AR-39; C₁~DMEM+10mg/L OxLDL;C₂~DMEM+10mg/L OxLDL+10 IFUs/L AR-39. 72 h later, morphological changes of the cells were observed and of intracellular cholesterol of content was detected. RESULTS: 1、Morphological studies: there were no lipid particles in A₁, A₂ and B₁ groups, but the lipid particles could be found in B₂、C₁ and C₂ group, Among six groups, the most lipid particles were seen in C₂ groups. 2、Biochemical detection:The ratio of cholesterol ester to total cholesterol was much higher than 50% in B₂、C₁ and C₂ groups, but was less than 50% in A₁、A₂ and B₁ groups. CONCLUSION: Chlamydia pneumoniae may have played a role in promoting C57 BL/6J mouse peritoneal macrophages into foam cells.     

ox-LDL increases endothelial lipase in RAW264.7 macrophages

AIM: To investigate the effect of oxidized low-density lipoprotein (ox-LDL) on the expression of endothelial lipase (EL) in murine RAW264.7 macrophages. METHODS: RAW264.7 cells were incubated with ox-LDL at concentrations of 0~100 mg/L for 24 h.On the other hand, the cells were incubated with or without PDTC (NF-κB inhibitor) for 30 min and then with ox-LDL (50 mg/L) for 24 h. The expression of EL and p65 was detected by Western blotting. RESULTS: The level of EL was significantly increased after ox-LDL incubation in RAW264.7 cells (P<0.05). NF-κB was activated by ox-LDL at concentration of 50 mg/L for 15~30 min in RAW264.7 cells. The increase in EL induced by ox-LDL was markedly inhibited by a NF-κB inhibitor PDTC (P<0.05). CONCLUSION: ox-LDL significantly increases the expression of EL in RAW264.7 macrophages, which is possibly related to NF-κB activation.     

Effect of 27nt-miRNA on apoptosis of human umbilical vein endothelial cells induced by oxidized low-density lipoprotein

AIM To investigate the effect of 27nt-miRNA （27nt-miR） on apoptosis of human umbilical vein endothelial cells （HUVECs） induced by oxidized low-density lipoprotein （Ox-LDL） and its underlying mechanism. METHODS HUVECs were cultured in vitro and grouped as below： normal control group, Ox-LDL group, 27nt-miR+Ox-LDL group, anti-27nt-miR+Ox-LDL group and negative control+Ox-LDL group. The cells in Ox-LDL group were treated with Ox-LDL at 40 mg/L for 48 h, while those in normal control group were untreated but cultured normally. The cells in 27nt-miR+Ox-LDL group, anti-27nt-miR+Ox-LDL group and negative control+Ox-LDL group were transfected with their corresponding lentiviral vectors under the same procedure, followed by treatment with Ox-LDL at 40 mg/L for 48 h to induce apoptosis. The cell viability was measured by CCK-8 assay. The migration capacity was detected by scratch assay. The caspase-3 activity was measured by caspase-3 activity assay kit. The apoptotic rate was analyzed by Hoechst 33258 and flow cytometry. The mRNA and protein expression levels of Bcl-2, Bax and caspase-3 were determined by RT-qPCR and Western blot. RESUITS： Compared with negative control+Ox-LDL group, the cell viability and migration ability were significantly decreased by over-expression of 27nt-miR in the HUVECs （P<0.05）, while the activity of caspase-3 and apoptosis induced by Ox-LDL were significantly increased （P<0.05）. Furthermore, the mRNA and protein expression levels of Bax and caspase-3 were significantly up-regulated （P<0.05）, and the mRNA and protein expression level of Bcl-2 was down-regulated in 27nt-miR+Ox-LDL group （P<0.05）. Meanwhile, all the above indexes showed an opposite tendency in anti-27nt-miR+Ox-LDL group. CONCLUSION 27nt-miR promotes Ox-LDL-induced apoptosis and inhibits the viability and migration of HUVECs in vitro, possibly through regulating the expression of apoptotic/anti-apoptotic proteins such as Bax,caspase-3 and Bcl-2.     

NaCl胁迫对葡萄幼苗叶片有机渗透调节物质和膜脂过氧化的影响

为阐明有机渗透调节物质在葡萄种质耐盐机理中的作用,以耐盐葡萄砧木抗砧5号(Vitis berlandieri-V.ri-paria×V.amurensis-V.vinifera)和盐敏感砧木Macadams(V.riparia)为试材,比较研究了在不同质量分数NaCl胁迫下,叶片膜透性、丙二醛(MDA)含量和有机渗透物质含量的变化。结果表明,盐胁迫引起葡萄叶片膜透性增加,盐敏感品种Macadams的膜透性高于耐盐砧木抗砧5号;MDA含量随盐胁迫加重而升高,但抗砧5号低于Macadams;盐胁迫下葡萄叶片中游离脯氨酸和可溶性糖含量显著上升;可溶性蛋白的变化趋势不一致。由此说明脯氨酸、可溶性糖是葡萄在盐胁迫初期的重要有机渗透调节物质,而可溶性蛋白在葡萄中的渗透调节作用还需要进一步研究。     

Oxidized low-density lipoprotein induces autophagy in macrophages via CD36-mediated oxidative stress

AIM: To investigate the effect of oxidized low-density lipoprotein (ox-LDL) on autophagy in macrophages and the underlying molecular mechanisms. METHODS: RAW264.7 macrophages were pretreated with 2 mg/L anti-CD36 monoclonal antibody (anti-CD36 mAb), 5 μmol/L diphenyleneiodonium (DPI), 3 mmol/L 3-methyladenine (3-MA) or 1 μmol/L rapamycin for 1 h and then treated with ox-LDL (100 mg/L) for 12 h. The viability of the cells was measured by MTT assay. The activities of lactic dehydrogenase (LDH) in the medium and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase (SOD) in the cells as well as the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) were determined to characterize the membrane integrity and the oxidative stress, respectively. The protein levels of beclin-1 and microtubule-associated protein 1 light chain 3-II (LC3-II), 2 important molecular markers of autophagy, were examined by Western blotting. RESULTS: ox-LDL induced autophagy in RAW264.7 macrophages as assessed by upregulation of beclin-1 and LC3-II. Similar to 3-MA, an autophagy inhibitor, anti-CD36 mAb significantly inhibited the ox-LDL-induced upregulation of beclin-1 and LC3-II. Anti-CD36 mAb suppressed the ox-LDL-induced oxidative stress as revealed by decreased NADPH oxidase activation, ROS and MDA generation as well as increased SOD activity. Similar results were observed in the cells pretreated with DPI, a NADPH oxidase inhibitor. Moreover, DPI significantly inhibited the ox-LDL-induced upregulation of beclin-1 and LC3-II. Inaddition, the decrease in the cell viability and increase in LDH release induced by ox-LDL were promoted by 3-MA and blocked by rapamycin (an autophagy inducer). CONCLUSION: ox-LDL induces autophagy in RAW264.7 macrophages, which may be involved in CD36-mediated ox-LDL uptake and subsequent activation of oxidative stress, and moderate activation of autophagy may protect macrophages from ox-LDL-induced injury.     

Role of Api6 in lung inflammation induced by high fat/cholesterol food in C57BL/6J mice

AIM：To investigate the function of apoptosis inhibitor 6 (Api6) in lung inflammation induced by high-fat high-cholesterol diet (HFD/HCD) in male C57BL/6J mice. METHODS：Male C57BL/6J mice (6~8 weeks old) were randomly divided into 2 groups and treated with regular diet and HFD/HCD, respectively. After 16 weeks of feeding, the lung tissues were collected and the pulmonary inflammatory status was determined by immunohistochemistry and ELISA. The mRNA and protein expression levels of Api6 were determined by real-time PCR and Western blotting. The apoptotic rate of bronchioalveolar lavage cells was examined by flow cytometry. RAW264.7 cells were cultured in vitro and the apoptosis induced by oxidized low-density lipoprotein (oxLDL) was detected by flow cytometry. RESULTS：Accumulation of macrophages and increases in both tumor necrosis factor α and monocyte chemoattractant protein 1 were observed in the lung tissues of 16-week HFD/HCD-fed C57BL/6J mice. Compared with the regular diet-fed mice, the expression of Api6 at mRNA and protein levels in the lung tissues was highly increased in the HFD/HCD-fed mice (P<0.01). Meanwhile, the apoptotic rate of bronchioalveolar lavage macrophages from the HFD/HCD-fed mice was highly inhibited (P<0.01). In vitro, 500 μg/L recombinant Api6 significantly inhibited the apoptosis of RAW264.7 cells induced by oxLDL (P<0.05). CONCLUSION：HFD/HCD feeding results in the accumulation of macrophages in the lung of C57BL/6J mice, which may partly due to the increased expression of Api6 and its anti-apoptotic role in macrophages.     

Nuciferine promotes autophagy and reduces macrophage foaming by inhibiting PI3K/Akt/mTOR signaling pathway

AIM To investigate the effect of nuciferine （NUF) on the formation of foam cells and its possible molecular mechanism. METHODS Human monocyte-macrophage cell line THP-1 was induced by oxidized low-density lipoprotein (Ox-LDL) to establish foam cell model, and simultaneously treated with NUF at 5, 10 or 20 μmol/L. Oil red O staining was used and total cholesterol content was measured to observe the effect of NUF on foam cell formation. Autophagy flow was detected by immunofluorescence, and autophagosomes were detected by transmission electron microscopy. The protein levels of microtubule-associated protein 1 light chain 3 (LC3), P62, phosphorylated protein kinase B (p-Akt) and phosphorylated mammalian target of rapamycin (p-mTOR) were determined by Western blot. 3-Methyladenine (3-MA), an autophagy inhibitor, was used to inhibit autophagy and to observe whether NUF inhibited foam cell formation by regulating autophagy. RESULTS Compared with control group, the intracellular lipid deposition and total cholesterol content in Ox-LDL group were increased. Compared with Ox-LDL group, the intracellular lipid deposition and total cholesterol content in NUF group were decreased, while autophagy flow and number of autophagosomes were increased. The inhibitory effect of NUF on cell foaming was weakened after 3-MA treatment. Moreover, NUF decreased the protein levels of p-mTOR and p-Akt. CONCLUSION Nuciferine may promote autophagy by inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR signaling pathway, thus reducing intracellular lipid deposition and formation of foam cells.     

Study on scavenger receptor A from mouse peritoneal macrophages

AIM: To study the role of scavenger receptor A(SR A) in the uptake of oxidized low density lipoprotein(OxLDL) in mouse peritoneal macrophages(MPM). METHODS: Comparing the difference of the uptake of OxLDL in SR A-deficient and wild-type MPM. RESULTS: The results showed that the binding of OxLDL wasn't apparently reduced in SR A-deficient MPM. The association of OxLDL was reduced by 35.8% and degradation of OxLDL was reduced by 42% in SR A-deficient MPM compared with those in wild-type MPM. CONCLUSION: Studies showed that SR A didn't play an important role in the uptake of OxLDL in MPM. Approximately 70% of the uptake of OxLDL in macrophages was attributable to non-SR A receptor.     

Effect of lipid peroxidation on expression of vascular cell adhesion molecule-1 in cultured human endothelial cells

AIM:To observe the expression of vascular cell adhesion molecule-1 (VCAM-1) in cultured human umbilical vein endothelial cells (HUVEC) by lipid peroxidation injury induced by exposure to diamide.METHODS:Expression of VCAM-1 mRNA and protein in HUVEC was determined by in situ hybridization and a cell enzyme-linked immunosorbent essay (cell ELISA), respectively.RESULTS:The HPIAS-1000 image analytic system in situ hybridization detected that the mean absorbance values in experiment groups(1, 5 and 10 μmol/L diamide for 8 hours) were 0.147±0.013, 0.292±0.020 and 0.396±0.022, which were 1.91-fold, 3.79-fold and 5.14-fold as much as that of the control group (0.077±0.011), respectively. There was significant statistical difference between groups (P＜0.01). The cell ELISA showed that the mean absorbance values of VCAM-1 proteins in experiment groups were 0.158±0.008, 0.220±0.017 and 0.321±0.023, which were 1.53-fold, 2.12-fold and 3.09-fold as much as that of the control group (0.104±0.016), respectively. The analysis of variance proved the significant difference between groups (P<0.01).CONCLUSION:The results suggest that the increased expression of VCAM-1 is integral in promoting adhesion of monocytes to the vascular endothelium.     

Lipid peroxidation precedes TNF and PDGF release in alveolar macrophage of the experimental pulmonary fibrosis rats

AIM:To evaluate the role of alveolar macrophage(AM)lipid peroxidation in bleomycin(BLM)-induced TNF-and PDGF release from AM in rats.METHODS:Male SD rats were intratracheal y instilled with saline or BLM(5 mg/kg body weight), and AM were isolated and analyzed for malondialdehyde(MDA)and glutathione peroxidase(GSH-Px)following 1, 3, 7, 14 or 28 day(s).Simultaneously, TNF-and platelet-derived growth factor(PDGF)were also determined in AM-conditoned media by ELISA and bioassay respectively.RESULTS:(1)MDA in AM was markedly increased on day1, peaked on day 3 and then decreased to near control level on day 7;on the other hand, GSH-Px activity in AM were decreased to non-detectable levels during day 1-7 after BLM instillat ion, returned to the control level by day 14.(2)TNF-and PDGF were increased significantly from the third day on and then exhibited a consectutive changes.(3)AM lipid peroxidation preceded TNF-and PDGF release.CONCLUSION:Prior oxidative changes leading to AM lipid peroxidation, depletion of antioxidative pool might be essential for the subsequent mediators release in BLM-induced pulmonary fibrosis.     

Effect of xeroderma pigmentosum group D gene on proliferation of human umbilical arterial smooth muscle cells induced by Ox-LDL

AIM: To investigate the effects of xeroderma pigmentosum group D (XPD) gene on the proliferation of human umbilical arterial smooth muscle cells (HUASMCs) induced by oxidized low-density lipoprotein (Ox-LDL). METHODS: The recombinant plasmid pEGFP-N2/XPD was transfected into HUASMCs by liposome. The cells were divided into blank control group, pEGFP-N2 group, pEGFP-N2/XPD group, Ox-LDL group, Ox-LDL+pEGFP-N2 group and Ox-LDL+pEGFP-N2/XPD group. The proliferation rate of the cells was detected by MTT and EdU assays. The apoptotic rate and cell cycle distribution were analyzed by flow cytometry. The protein levels of XPD, caspase-3, Bcl-2 and Bax were determined by Western blot. RESULTS: Compared with blank control group, the expression of XPD was increased in pEGFP-N2/XPD group (P<0.05). According to the results of MTT and EdU assays, the cell proliferation in pEGFP-N2/XPD group was reduced compared with blank control group (P<0.05). Compared with Ox-LDL group, the cell proliferation in Ox-LDL+pEGFP-N2/XPD group was significantly inhibited (P<0.05). According to the results of flow cytometry, the cell proportion of S phase decreased and the G₀/G₁-phase cell proportion increased significantly in pEGFP-N2/XPD group and Ox-LDL+pEGFP-N2/XPD group compared with blank control group and Ox-LDL group, repectively (P<0.05). Compared with blank control group and Ox-LDL group, the protein level of Bcl-2 decreased and the protein levels of Bax and cleaved caspase-3 increased in pEGFP-N2/XPD group and Ox-LDL+pEGFP-N2/XPD group, respectively (P<0.05). CONCLUSION: XPD inhibits the proliferation of HUASMCs and promotes their apoptosis, and reduces the promoting effect of Ox-LDL on the proliferation of HUVSMCs. XPD may be the target for treatment of atherosclerosis.     

Effects of oxidized low density lipoprotein and lysophosphatidylcholine on cholesterol efflux from mouse peritoneal macrophage foam cells

AIM:To explore the effects of oxidized low density lipoprotein (OxLDL) and one of its component— lysophosphatidylcholine (LPC) on cholesterol efflux from mouse macrophage foam cells.METHODS:(1) Cholesterol efflux induced by apoAI from mouse peritoneal macrophage foam cells loaded with OxLDL or acylated LDL(AcLDL) was measured. (2) Cholesterol efflux induced by LPC and apoAI from macrophage foam cells separated from normal or apoE gene deficient (E⁰) mouse loaded with AcLDL were measured.RESULTS:(1) When the macrophage foam cells were incubated with apoAI, cholesterol efflux from AcLDL-induced macrophage foam cells increased significantly compared to that of OxLDL-induced macrophage foam cells. (2) LPC promoted cholesterol efflux from macrophage foam cells in relation to both dosage and time. When LPC was incubated with E⁰ mouse macrophage foam cells, the released cholesterol mass was significantly lower than that of normal mouse macrophage foam cells. It was also found that cholesterol efflux induced by apoAI normally occurred in E⁰ mouse macrophage foam cells.CONCLUSIONS:(1) OxLDL accumulated cholesterol in macrophages and impair cholesterol efflux. (2) LPC induced cholesterol efflux from macrophage foam cells, which may occur via apoE pathway.     

Exogenous polyamines alleviate the lipid peroxidation induced by cadmium chloride stress in Malus hupehensis Rehd.

In order to investigate the effects of spermidine (Spd) and spermine (Spm) on the stress of cadmium chloride (CdCl₂), it was checked that the content of polyamines and malondialdehyde (MDA), the rate of superoxide anion (O₂⁻) generation and the activities of superoxidase dismutase (SOD) and guaiacol peroxidase (GPX) in 1-year-old Malus hupehensis Rehd. var. pinyiensis Jiang (tea crabapple) seedlings grown in nutrient solution. The result showed that the content of free putrescine (Put) was increased, the contents of free Spd and Spm and the (Spd + Spm)/Put ratio in leaves were decreased significantly under CdCl₂ treatment. Foliar spraying with Spd or Spm under CdCl₂ treatment, the accumulation of free Put reduced, the contents of free Spd and Spm and the ratio of (Spd + Spm)/Put in leaves increased significantly. The activities of SOD and GPX in leaves were enhanced and O₂⁻ generation rate and MDA content were decreased significantly by foliar spraying with Spd or Spm under CdCl₂ treatment. Results suggest that both Spd and Spm can alleviate the lipid peroxidation caused by CdCl₂ in M. hupehensis var. pinyiensis.     

Effects of HDL from patients with coronary artery disease on lipid deposition and apoptosis in mouse peritoneal macrophages

AIM: To compare the effects of high-density lipoprotein (HDL) from healthy subjects (HDL_heathy) and HDL from the patients with coronary artery disease (HDL_CAD) on the lipid deposition and apoptosis in mouse peritoneal macrophages. METHODS: HDL was isolated from healthy subjects, stable CAD patients (HDL_SCAD) and acute myocar-dial infarction patients (HDL_AMI). The accumulation of intracellular lipids was determined by oil red O staining. The apoptosis of macrophages was measured by fluorescence microscopy with annexin-V/PI staining. DCHF-DA, a redox-sensitive dye, was used to detect intracellular reactive oxygen species (ROS) levels. The protein expression of ATP-binding cassette transporter (ABC) A1, ABCG1, Bcl-2 and Bax was determined by Western blot analysis. RESULTS: Lipid deposition in the macrophages was increased significantly after oxidized low-density lipoprotein (ox-LDL) treatment, and the expression of ABCA1 and ABCG1 was up-regulated (P<0.05). Compared with ox-LDL treatment alone, HDL_healthy decreased lipid deposition in the macrophages and up-regulated the expression of ABCA1 and ABCG1 (P<0.05), while treatment with HDL_SCAD or HDL_AMI further decreased lipid deposition in the macrophages and down-regulated the expression of ABCA1 and ABCG1 (P<0.05). Compared with HDL_SCAD treatment, lipid deposition in the macrophages was further increased after HDL_AMI treatment, and the expression of ABCA1 and ABCG1 was down-regulated (P<0.05). HDL_healthy decreased the levels of intracellular ROS and apoptosis by increasing the level of antiapoptotic protein Bcl-2 and reducing the expression of proapoptotic protein Bax. In contrast, HDL_SCAD and HDL_AMI had opposite effects on the intracellular ROS, the cell apoptosis and the expression of apoptosis-related proteins Bcl-2 and Bax. CONCLUSION: HDL_CAD promotes lipid accumulation in macrophages and induces macrophage apoptosis. These findings provide novel insights into mechanisms leading to altered vascular effects of HDL in CAD.     

Curcumin inhibits lipid peroxidation and the expression of TGF-β1 and PDGF in the liver of rats with hepatic fibrosis

AIM: To investigate changes of the level of reactive oxygen species (ROS),malondialdehyde (MDA),transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF) expression in a rat hepatic fibrosis model and the effect of curcumin ,and discuss the mechanism of the prophylactic effect of curcumin on hepa tic fibrosis.METHODS: Rat models of hepatic fibrosis were established by intraperitoneally injection of carbon tetrachloride.Curcumin of 20 mg,10 mg,5mg per 100 gram weight of rat was given to these rats respectively at the same time.Normal,fibrosis model and positive groups were made as controls.After eight weeks,all rats were executed and the blood and liver were kept.Serum level of ROS was tested by chromatometry.Content of MDA in liver homogenate was tested by thiobarbituric acid (TBA) method.Expressions of TGF-β1 and PDGF in liver were detected by immunohistochemical method. RESULTS: Serum level of ROS in fibrotic group increased significantly compared with that of normal group,and which was depressed obviously in curcumin groups(P＜0.05).Content of MDA in liver of curcumin group reduced significantly compared with that of fibrotic group (P＜0.01).Expressions of TGF-β1 and PDGF in fibrotic group increased significantly compared with those of normal group,which were depressed obviously in curcumin groups (P＜0.01).CONCLUSION: Curcumin could inhibit expression of TGF-β1,PDGF and lipid peroxidation in liver.These may be mechanisms of curcumin preventing hepatic fibrosis.