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To observe the effects of diabetogenic (high fat high sucrose, lacking choleserol) diet on atherogenesis in New Zealand white rabbits. Two groups of New Zealand white rabbits received regular rabbit chow (the normal control), or high fat high sucrose diet for 4 months. The levels of plasma total cholesterol, HDL cholesterol, triglycerides, insulin, and glucose were investigated, the areas of fatty streak of the aortae were measured after staining with Sodan IV, and the aortic, coronary specimens were observed with light and electron microscopies. The plasma glucose, triglycerides, and total cholesterol were increased significantly by high fat high sucrose feeding. At the end of 4 months, the early charateristics of atherosclerosis were present in the animals' vascular specimens. Our findings suggest that high fat high sucrose feeding can induce hyperglycemia, hypertriglyceridemia and atherosclerosis in New Zealand white rabbits, and this could be a potential animal model for studying the mechanisms of diabetes-accelerated atherosclerosis. This study raised a question: What is the mechanism by which high fat high sucrose feeding induces atherosclerosis?. The related hypothesis was given in this article.
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AIM:Vascular smooth muscle cell (SMC) proliferation and migration from the arterial wall media into the intima are believed to play a critical role in the pathogenesis of restenosis. Several studies have demonstrated that phosphothioate (PS) oligodeoxynucleotides targeted against genes involved in SMC proliferation inhibits in vitro SMC proliferation and migration. However, the therapeutic effect of antisense ODN on the individual who receives the treatment of delivery of the agent depends on the efficacy of this agent in great degree. We investigated the inhibition effect of a novel agent, insulin-antisense-c-myb-PS-ODN on SMC proliferation in vitro. METHODS：The rat aortic artery SMCs were cultured in Dulbecco's modified Eagel's medium. The passage 8 to 13 were used as the experiment. Cell surface receptor binding assay was quantified through counting gamma particles emitted from 125 I labeled insulin. SMC rapid proliferation was brought by stimulation of high concentration of fetal bovine serum (FBS). The novel agent of insulin conjugated to the antisense-c-myb-PS-ODN was obtained via incubation of both in condition of certain reagents, pH, temperature, and ion concentration. The characterization and purification of the agent was performed through HPLC. Inhibition of SMC proliferation was reflected by incorporation rate of trillium labeled thymidine deoxyribonucleotide.RESULTS：The binding efficacy of insulin to the receptor was remarkably increased in SMC cultured in supplement of 20% FBS. The inhibition effect of conjugator insulin-c-myb-antisense-PS-ODN was stronger than that of the simple c-myb-antisense-PS-ODN. The inhibition rate of conjugator and simple form on SMC proliferation were 48.34% and 29.54%, respectively. CONCLUSION：The binding efficacy and specificity of c-myb-antisense-PS-ODN to SMC may be enhanced by the insulin receptor mediation through the insulin-insulin receptor interaction. The insulin-receptor targeted method may be a potential and specific therapeutic pathway for restenosis.
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AIM: To study the effects of apolipoprotein (apo) A-Ⅰon ATP binding cassette transporter A1 (ABCA1) degradation and cholesterol efflux in THP-1 macrophage-derived foam cells. METHODS: After exposure of the cultured THP-1 macrophage-derived foam cells to apolipoprotein A-Ⅰ for different time, cholesterol efflux, ABCA1 mRNA and protein level were determined by liquid scintillation counting, reverse transcriptase-polymerase chain reaction and Western blotting, respectively. The mean ABCA1 fluorescence intensity on THP-1 macrophage-derived foam cells was detected by flow cytometry. RESULTS: ApoA-Ⅰ markedly increased ABCA1-mediated cholesterol efflux from THP-1 macrophage-derived foam cells. This was accompanied by an increase in the content of ABCA1. ApoA-Ⅰ did not alter ABCA1 mRNA abundance. Thiol protease inhibitors increased the level of ABCA1 protein and slowed its decay in THP-1 macrophage-derived foam cells, whereas none of the proteosome-specific inhibitor lactacystin, other protease inhibitors, or the lysosomal inhibitor NH_4Cl showed such effects. The apoA-Ⅰ mediated cellular cholesterol efflux was enhanced by thiol protease inhibitors. CONCLUSION: Thiol protease inhibitors might provide an alternative way to upregulate ABCA1 protein. This strategy is especially appealing since it may mimic the stabilizing effect of the natural ligands apoA-Ⅰ.
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AIM: In order to investigate the change of CD36 expression in atherosclerosis. METHODS: Chinese minipigs were fed a normal control diet (CD) or a high fat/high cholesterol diet (HFHC) for 12 months after common carotid artery injury induced by balloon denudation. Plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were determined by commercially enzymatic methods. CD36 mRNA and protein levels were determined by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry, respectively. RESULTS: After HFHC for 12 months, plasma total cholesterol, HDL cholesterol and triglyceride in HFHC minipigs were increased compared with the control. CD36 expression and aorta PPAR? in HFHC minipigs were upregulated. CONCLUSION: HFHC may induce hyper cholesterolemia, hypertriglyceridemia and upregulation of CD36 and aortic PPAR? expression.
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AIM: To study the action of ATP binding cassette transporter(ABC) A 1 on cholesterol efflux in THP-1 macrophage-derived foam cells. METHODS: After exposure of the cultured THP-1 macrophage-derived foam cells to 22(R)-hydroxycholesterol and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) at different concentration for 24 hours, cholesterol efflux and ABCA1 mRNA level were determined by FJ-2107P type liquid scintillator and reverse trancriptase-polymerase chaim reaction(RT-PCR), respectively. RESULTS: Oxidized LDL promoted cholesterol efflux in THP-1 macrophages and 22(R)-hydroxycholesterol increased cholesterol efflux in THP-1 macrophage-derived foam cells in a dose-dependent manner and DIDS inhibited cholesterol efflux in THP-1 macrophage-derived foam cells in a dose-dependent manner. Exposure of the cultured THP-1 macrophage-derived foam cells to 22(R)-hydroxycholesterol and DIDS at different concentration for 24 hours, resulted in increase and decrease in the expression of ABCA1 mRNA in THP-1 macrophage-derived foam cells in a dose-dependent manner, respectively. CONCLUSION: ABCA1 playes an important role in cholesterol efflux in THP-1 macrophage-derived foam cells.
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AIM: Based on the finding of adipophilin expression with the increase in cellular cholesterol, the aim of the present study was to look for the active site of adipophilin in cellular cholesteryl metabolism. METHODS: Mouse peritoneal macrophages were incubated with 80 mg/L Ox-LDL (Ox-LDL group) or 80 mg/L Ox-LDL plus 1 mmol/L adipophilin antisense oligonucleotides (Ox-LDL+antisense group), respectively. At the various time points, the incubated cell samples were observed with adipophilin immunofluorescence staining, flow cytometric analysis and cellular cholesterol analysis. RESULTS: The Ox-LDL+antisense group cells contained significantly lower cholesteryl ester (19.9?1.9) mg/g (protein) than that of cells in Ox-LDL group (46.6?3.4) mg/g (protein) at 4 days. From 12 h, expression of adipophilin in Ox-LDL group increased more quickly than that of the cells in Ox-LDL+antisense group. At day 4, the level of adipophilin expression in Ox-LDL group was significantly higher than that in Ox-LDL+antisense group. During the observation, the amount of Ox-r[CL-3H] LDL taking up increased gradually in both groups, however, from day 1 the taking up amount in Ox-LDL+antisense group was less than that in Ox-LDL group. There was a statistical difference between the two groups from day 2 to day 4. From 6 h to day 2, the relative ACAT activity increased in both groups. The relative ACAT activity kept unchanged from day 2 to day 4 in the two groups. At day 2, the relative ACAT activity in Ox-LDL+antisense group was significantly lower than that in Ox-LDL group. Correlative analysis between activity of ACAT and adipophilin expression showed than R2 were 0.6176 and 0.8212 (P
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AIM: To investigate the relationship betw een ADRP and the development of atherosclerosis. METHODS: Antisense oligodeoxynucleotide of mouse ADRP was constr ucted. The mouse peritoneum macrophages were cultured with Ox-LDL or Ox-LDL plus the antisense fragment. The cellular cholesterol was measured and the expressio n of ADRP was observed with RT-PCR and western blotting. New Zealand white rabbi ts were fed with high cholesterol chow for 12 weeks. The levels of serum lipid a nd cholesterol content of aortic wall were investigated. The areas of fatty stre ak of the aortas was measured after staining with Sudan Ⅳ. The aortic, and live r specimens with HE and immunohistochemistry staining were observed under light microscopes. RESULTS: Antisense oligodeoxynucleotides of mouse ADRP decreased cellular cholesterol ester, induced cellular lipid droplets and the expression of ADRP. The expression of ADRP was induced by high-cholesterol-diet feeding in rabbit atherosclerotic lesions. The fatty streak of the aorta with immunohistoch emistry staining was strongly positive for ADRP in animals fed with high cholest erol chow, and the liver was negative with or without high cholesterol chow. CONCLUSIONS: The expression of ADRP in vessel walls is related t o the atherosclerosis, and has a potential role in lipid accumulation in macroph ages and pathogenesis of atherosclerosis.
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AIM: Anti-atherosclerosis effects of Momordica charantia L was further studied in a New Zealand rabbit atherosclerotic model at the basis of anti-inflammation and antioxidant effects. METHODS: Animals were divided into 3 groups: normal group (normal rabbit diet), atherosclerosis group(diet containing 2% cholesterol), and Momordica charantia L group(diet containing 2% cholesterol and 1 5% sarcocarp of Momordica charantia L ). Ninety days later, all animals were sacrificed. The effect of Momordica charantia L on atherosclerosis was evaluated by measuring serum lipid and total cholesterol content of artery wall, observing fatty liver degree, aorta arteriosclerotic area, and the thickness of intima. RESULTS: The level of total serum cholesterol and LDL-C in Momordica charantia L treatment group were obviously lower than those in atherosclerosis group, so were the total cholesterol content of artery wall, fatty liver degree, atherosclerotic area, intima thickness and I/M ratio, but no significantly difference was found between the two groups in TG level. The level of HDL-C in Momordica charantia L treatment group was evidently lower than that in normal control group. CONCLUSION: Momordica charantia L has an anti-atherosclerosis action in rabbits.