高浓度胰岛素对兔视网膜Müller细胞表达血管内皮生长因子的影响

目的探讨高浓度胰岛素对体外培养的视网膜Müller细胞表达血管内皮生长因子(VEGF)的影响.方法采用免疫细胞化学法、原位杂交法及ELISA法,定性、定量测定在不同浓度胰岛素条件下,体外培养的兔视网膜Müller细胞表达VEGF的变化.结果胰岛素能明显增强VEGF的表达,并通过转录水平调节.结论高浓度胰岛素可能通过刺激Müller细胞编码VEGF基因的转录,增强VEGF蛋白的表达,从而加速糖尿病视网膜病变的新生血管形成.     

高糖对体外培养的视网膜Müller细胞膜离子通道的影响

目的 观察在高浓度葡萄糖条件下，体外培养的兔视网膜Müller细胞的钙依赖性钾(K_Ca)通道的变化。 方法 高浓度葡萄糖条件下体外培养兔视网膜Müller细胞，并用免疫组织化学染色及透射电镜鉴定培养的Müller细胞，采用膜片钳方法观察不同时间高糖条件下视网膜Müller细胞K_Ca通道的变化。 结果 高糖对体外培养的Müller细胞K_Ca通道有阻滞作用，其阻滞作用呈时间依赖性。 结论 高浓度葡萄糖可能通过阻滞K Ca通道而降低 Müller细胞的生物学功能。 （中华眼底病杂志，2003，19：164-167）     

缺氧对视网膜Müller细胞促红细胞生成素mRNA和蛋白表达的影响

目的 探讨缺氧条件下促红细胞生成素（EPO）mRNA及蛋白在体外培养的Müller细胞的表达情况。 方法 胰酶消化新生大鼠视网膜组织制成单细胞悬液，机械震荡、吹打法分离纯化视网膜Müller细胞，反转录-聚合酶链反应（RT-PCR）、免疫细胞化学方法对缺氧条件下视网膜Müller细胞EPO基因和蛋白的表达进行测定。 结果 成功获得视网膜Müller细胞，传代后95%以上的细胞呈神经胶质纤维酸性蛋白（GFAP）染色阳性。EPO蛋白的阳性染色位于视网膜Müller细胞的细胞浆及突起上。在正常的视网膜Müller细胞中仅见微弱的EPO mRNA和蛋白表达，而缺氧后表达明显上调，且呈时间依赖性。 结论 Müller细胞在缺氧条件下EPO mRNA和蛋白表达增强，EPO表达水平的升高可能是缺氧性视网膜病变的神经保护因素之一。 (中华眼底病杂志, 2006, 22: 196-199)     

阿柏西普对体外培养的视网膜Müller细胞膜离子通道的影响

目的：探讨阿柏西普对体外培养的高糖环境下视网膜Müller细胞膜K⁺通道的影响。

方法：人Müller细胞分为3组：对照组(常规DMEM培养基培养)、高糖组(高糖DMEM培养基培养)、实验组(高糖DMEM培养基和100μmol/L 阿柏西普处理)。采用荧光探针检测细胞K⁺浓度,MTT法检测细胞存活率,流式细胞仪检测细胞凋亡率,Western blot法检测Müller细胞caspase-3蛋白水平。

结果：Müller细胞培养48h后呈现谷氨酰胺合成酶(GS)阳性,纯化度在90%以上。荧光检测显示对照组、高糖组、实验组K⁺相对浓度分别为(2.14±0.44)%、(23.11±4.39)%、(5.20±0.92)%,细胞存活率分别为(100.00±0.00)%、(73.24±4.13)%、(85.22±5.33)%,细胞凋亡率分别为(5.03±1.91)%、(26.73±3.14)%、(16.63±2.73)%(均P<0.05)。 与对照组相比,高糖组Müller细胞内caspase-3蛋白水平显著上升(P<0.05); 与高糖组Müller细胞相比,实验组Müller细胞内caspase-3蛋白水平显著降低(P<0.05)。

结论：阿柏西普可抑制体外培养的高糖环境下视网膜Müller细胞膜K⁺通道,抑制高糖诱导的Müller细胞凋亡,降低caspase-3蛋白表达水平,促进细胞增殖。     

兔视网膜Müller细胞的原代培养

目的 探索体外培养兔视网膜Müller细胞的有效方法.方法 采用酶消化法从乳兔视网膜获取Müller细胞,通过振荡和反复洗涤使之纯化.采用免疫组织化学技术和透射电镜对传代Müller细胞进行鉴定.结果 培养24 h后即有部分细胞贴壁生长,72 h后贴壁细胞进一步增多.通过振荡吹打可使附着于Müller细胞上的神经元脱落.20～25 d后细胞接近融合,呈三角形或不规则形.传代后细胞经1周达到融合.培养细胞GFAP阳性率在95%以上.电镜观察显示细胞内含有线粒体、粗面内质网、核糖体及8～10 nm的中间丝.结论 利用酶消化法可成功分离兔视网膜Müller细胞,通过振荡和吹打洗涤,可使之纯化.     

Müller细胞对视网膜血管内皮细胞紧密连接蛋白表达的影响

目的
探讨体外培养的Müller细胞在糖基化终末产物（AGEs）作用下增殖活性的变化，以及这种改变对牛视网膜血管内皮细胞（BREC）紧密连接蛋白（occludin）表达的影响。
方法
培养新生大鼠Müller细胞和BREC，两类细胞均用特异性抗体进行免疫鉴定。将培养的BREC分4组观察：第1组未添加任何细胞上清液；第2组添加正常Müller细胞上清液；第3组添加糖基化终末产物(AGEs)作用后的Müller细胞上清液；第
4组无细胞组，为空白对照组。酶联免疫吸附法（ELISA）测定4组细胞上清液中紧密连接蛋白的含量，比较其变化。
结果
添加正常Müller细胞上清液组紧密连接蛋白表达量最多，未添加任何细胞上清液组次之，添加AGEs作用后的Müller细胞上清液组更少。
结论
AGEs能促进Müller细胞异常增殖、抑制BREC表达紧密连接蛋白。
(中华眼底病杂志, 2006, 22: 28-30)     

黄连素对高糖培养下大鼠视网膜Müller细胞增殖的影响

目的：研究黄连素对体外高糖环境下的SD大鼠视网膜Müller细胞增殖的影响。

方法：采用酶消化法原代培养SD大鼠视网膜Müller细胞,将第2代Müller细胞随机分为正常糖浓度(5mmol/L)组、高糖浓度(25mmol/L)组、高糖+不同浓度(5、10、25、50、100μmol/L)黄连素组,分别培养24、48、72h后,采用CCK-8法检测细胞增殖活性。

结果：培养24、48、72h时,高糖浓度组Müller细胞吸光度值较正常糖浓度组明显降低(均P<0.01); 10、25、50、100μmol/L黄连素组细胞吸光度值较高糖浓度组明显升高(均P<0.05),且呈剂量依赖性; 5μmol/L黄连素组细胞吸光度值与高糖浓度组无明显差异(P>0.05)。

结论：黄连素在一定程度上能够减轻高糖对Müller细胞增殖活性的抑制作用,其作用强度与黄连素浓度呈正相关。     

转化生长因子α对鼠视网膜Müller细胞谷氨酸转运体调控作用的研究

目的 观察转化生长因子α（TGFα）对鼠视网膜Müller细胞谷氨酸转运体 (GLAST) mRNA、蛋白质表达及摄取活性的调控作用。方法 取出生后7～10 d 的新生昆明小鼠视网膜组织，体外进行Müller细胞的培养。同一原代细胞的第3～4代细胞培养后随机分为2组：①TGFα干预组：分别加入浓度为50、75、125、150 ng/ml的TGFα，每种浓度3孔；②对照组：仍用含20%胎牛血清的Dulbeccon改良Eagle培养基培养。采用L-3H-谷氨酸摄取分析方法观察不同浓度TGFα对Müller细胞GLAST摄取活性的影响；逆转录聚合酶链反应方法分析Müller细胞GLAST mRNA表达的差异；免疫组织化学染色方法检测Müller细胞GLAST蛋白质表达的变化。结果随着TGFα浓度的增加，L-3H-谷氨酸的摄取量及GLAST mRNA表达量均逐渐增加，TGFα浓度为125 ng/ml时，L-3H-谷氨酸的摄取量达到最大值，为对照组的266%，同时GLASTmRNA表达量也达到最大值，为对照组的近4倍。免疫组织化学染色显示当TGFα浓度为125 ng/ml时，干预组Müller细胞内的GLAST蛋白表达量明显高于对照组，差异具有统计学意义（P＜0.05）。结论 TGFα可通过上调GLAST mRNA和蛋白质的表达增加视网膜Müller细胞谷氨酸转运体GLAST的摄取活性。     

高浓度胰岛素对视网膜Müller细胞VEGF表达的影响(英文)

目的:探讨在高浓度胰岛素条件下,体外培养的兔视网膜Müller细胞的血管内皮细胞生长因子(vas-cularendothelialgrowthfactor,VEGF)的变化。方法:在不同浓度胰岛素条件下(4,8,12kU/L),体外培养兔视网膜Müller细胞,采用免疫细胞化学法、原位杂交法,定性测定Müller细胞分泌VEGF的变化,采用ELISA方法,定量测定Müller细胞分泌VEGF的变化。结果:高浓度胰岛素能明显增强VEGF的表达(P< 0.05)。结论:高浓度胰岛素可能通过刺激Müller细胞编码VEGF基因的转录,进而增强VEGF蛋白的表达,而在糖尿病视网膜病变的新生血管生成中发挥重要作用。     

糖尿病视网膜Müller细胞病理改变的体内外研究

目的研究糖尿病视网膜Müller细胞的病理改变.方法用链脲菌素(STZ)腹腔注射建立大鼠糖尿病模型,3个月后观察视网膜Müller细胞超微结构的变化.行免疫组织化学染色,在激光共聚焦显微镜下观察视网膜Müller细胞GFAP、VEGF表达的改变;纯化培养出生5～7d(SD)乳鼠的Müller细胞,在其中加入糖基化终末产物(AGEs)2500μg/mL,培养24h后,用MTT方法检测细胞活性.结果3个月后电镜观察发现糖尿病鼠视网膜Müller细胞突起有损伤表现,微血管内皮细胞、周细胞未见病理改变;正常鼠视网膜VEGF染色阴性,视网膜内界膜下、神经节细胞层有GFAP染色;糖尿病鼠除视网膜内界膜下、神经节细胞层有GFAP染色外,其余各层也可见丝条状贯穿于内外界膜之间的GFAP染色,在上述部位有VEGF及GFAP的共表达.培养24h后,2500μg/mL质量浓度的AGEs对Müller细胞活性有显著促进作用.结论反应性胶质化增生可能是糖尿病早期Müller细胞的主要病理改变,它所引起的Müller细胞结构和功能改变应在糖尿病视网膜病变(DR)的发生发展中起重要作用.AGEs可能是DR中视网膜Müller细胞反应性胶质化增生的重要致病因素.     

缺氧条件下高糖及高胰岛素对Mller细胞VEGF表达的影响

目的观察缺氧、高糖及高胰岛素对视网膜Muller细胞胞浆内血管内皮生长因子（VEGF）表达的影响。方法采用组织块悬浮贴壁法原代培养兔视网膜Miiller细胞,于正常和缺氧条件下分别分为对照组、高糖组、高浓度胰岛素组、高糖高浓度胰岛素组,通过AO／EB染色法观察不同缺氧时相Mtiller细胞的凋亡情况,免疫细胞化学染色测定各组Mailer细胞胞浆内VEGF的表达。结果免疫细胞化学技术测定结果显示缺氧条件下1、2、3d各实验组与对照组相比VEGF表达量增加差异均有统计学意义（P〈0．05）。缺氧2d、3d各实验组与正常条件下各实验组相比VEGF表达增加,差异均有统计学意义（P〈0．05）。结论缺氧条件下高糖及高胰岛素环境刺激Mtiller细胞VEGF表达作用增强。     

Glucose-induced activation of glucose uptake in cells from the inner and outer blood-retinal barrier

PURPOSE: The purpose of this study was to elucidate in vitro the effect of elevated glucose on glucose uptake in the cells comprising the inner and outer blood-retinal barriers: human retinal pigment epithelial (hRPE) and human retinal vascular endothelial (hRVE) cells. METHODS: Primary cultures of hRPE and hRVE cells grown in 5.5 or 22 mM glucose or in 22 mM mannitol were used to measure the rates of glucose uptake with [(3)H]-3-O-methyl glucose as a tracer. GLUT1 expression was measured by Northern and western blot analyses. Cellular fractionation was performed by differential centrifugation. GLUT1 overexpression was accomplished by adenoviral transduction. RESULTS: Increasing media glucose from 5.5 to 22 mM for 30 minutes caused a 1.9-fold increase in the V(max) of glucose uptake in hRPE cells and a 2.5-fold increase in hRVE cells. These increases were nonosmotic and glucose specific, in that the exposure to 22 mM mannitol did not affect the V(max) of glucose uptake. mRNA, total protein expression, and translocation of GLUT1, the glucose transporter predominantly expressed in hRPE and hRVE cells, were not affected by 22 mM glucose for up to 48 hours. High-glucose effects on V(max) were abolished with 10 microg/mL of the microtubule assembly inhibitor nocodazole. hRPE cells transduced to overexpress GLUT1 showed a 1.5-fold increase in the V(max) for glucose uptake versus control-transduced cells. However, the magnitude of glucose-induced increase in glucose uptake was the same in GLUT1- and control-transduced cells. CONCLUSIONS: High glucose induced 1.9- and 2.5-fold increases in the V(max) of glucose uptake in hRPE and hRVE cells, respectively. These increases were not due to an increase in GLUT1 expression. The increases were dependent on microtubule integrity, but not on GLUT1 translocation. The mechanism of the increases is unknown. GLUT1 regulating protein(s) and/or novel glucose transporter(s) may be involved in the regulation of glucose uptake by glucose in the cells that comprise the blood-retinal barrier.     

Increased JNK phosphorylation and oxidative stress in response to increased glucose flux through increased GLUT1 expression in rat retinal endothelial cells

PURPOSE: To investigate whether increased glucose flux through increased glucose transporter1 (GLUT1) expression results in increased oxidative stress and increased c-jun N-terminal kinase (JNK) phosphorylation. METHODS: GLUT1-overexpressing cells were established using a rat retinal endothelial cell line. The intracellular reactive oxygen species was detected by the oxidation of 5- (and -6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2-DCFDA). Western blot was performed to determine JNK phosphorylation and lipid peroxidation. Differentially expressed genes were detected by cDNA microarray analysis and confirmed by Northern blot analysis. RESULTS: Clones overexpressing GLUT1 showed an approximate four- to eightfold increase in GLUT1 expression and a 44% increase in intracellular glucose concentrations. GLUT1-overexpressing cells had a 80% increase in DCF fluorescence and increased lipid peroxidation, as well as increased JNK phosphorylation. Analysis of differentially expressed genes in GLUT1-overexpressing cells showed increased expression of JNK interacting protein (JIP)-1, a scaffold protein necessary for JNK activation. Northern blot analysis confirmed upregulation of JIP-1. Immunoprecipitation showed that phosphorylated JNK, but not total JNK, coimmunoprecipitated with JIP-1 protein. At the cellular level, JIP-1 was predominantly localized in cytoplasm, especially in the perinuclear area in retinal endothelial cells. CONCLUSIONS: GLUT1 overexpression and increased glucose flux result in increased oxidative stress and JNK phosphorylation in immortalized rat retinal endothelial cells. Further studies are needed to understand molecular events after increased glucose flux in retinal endothelial cells and the relation between increased oxidative stress and JNK phosphorylation.     

蛋白激酶C活性调节剂对豚鼠近视眼视网膜Mller细胞的作用及意义

目的研究蛋白激酶C（PKC）激活剂PMA和抑制剂GF109203X对豚鼠近视眼视网膜Mailer细胞生长状态及PKC蛋白表达的影响。方法眼罩遮盖诱导近视模型,酶消化法培养其视网膜Mailer细胞,并鉴定。PMA、GF109203X分别干预近视眼Mailer细胞。MTT测细胞活力,TUNEL染色检测凋亡细胞,Westren blotting测PKC蛋白表达。结果95％以上的培养细胞阳性表达胶质纤维酸性蛋白（GFAP）和波形蛋白（Vimentin）。近视组PKC蛋白表达较正常组上调（P〈0．05）。PMA、GF109203X均能引起近视眼Mailer细胞的抑制率升高和诱导其凋亡（P〈0．05）。PMA诱导近视眼Mailer细胞PKC蛋白表达进一步上调,100nmol／L组和1000nmol／L组表达量高于10nmol／L组（P〈0．05）。1μmol／L和10μmol／L GF109203X均能引起近视眼Mailer细胞PKC蛋白表达下调,10μmol／L的抑制作用大于1μmol／L（P〈0．05）。结论PKC蛋白在豚鼠近视眼视网膜Mailer细胞表达升高,且其表达受PMA和GF109203X调控。     

Inner blood-retinal barrier GLUT1 in long-term diabetic rats: an immunogold electron microscopic study

PURPOSE: The GLUT1 glucose transporter mediates glucose entry into the endothelial cells of the inner blood-retinal barrier (BRB). In many cell types, exposure to high glucose concentrations or diabetes downregulates GLUT1. To determine whether long-standing diabetes alters the expression and distribution of inner BRB GLUT1, changes in immunoreactive retinal endothelial cell GLUT1 were studied in Goto-Kakizaki (GK) rats, an animal model of type 2 diabetes. METHODS: Immunogold staining for GLUT1 was performed on ultrathin sections of retinal specimens obtained from 1-year-old GK rats and age-matched Wistar controls. Retinal capillary endothelial cells were visualized by transmission electron microscopy, and GLUT1 immunogold was quantified on the luminal and abluminal membranes of endothelial cells from digital microphotographs of individual vessels by computer. RESULTS: Forty-one microvessels from six diabetic rats and 43 microvessels from six nondiabetic Wistar control rats were analyzed. Densitometric quantification revealed an asymmetry of GLUT1 distribution between luminal and abluminal membranes of both diabetic and nondiabetic rats, with a luminal-to-abluminal ratio of approximately 1 to 3. The distribution pattern and density of retinal endothelial GLUT1 immunoreactivity were not significantly different between the diabetic and control rats. CONCLUSIONS: As determined by GLUT1 immunogold distribution, there is no compensatory downregulation of GLUT1 on the inner BRB in an animal model of long-standing diabetes.     

PKC对豚鼠近视眼视网膜Mller细胞近视因子基因的调控作用

目的研究蛋白激酶C（PKC）对豚鼠近视眼视网膜Mtiller细胞中酪氨酸羟化酶（TH）、诱导型NO合成酶（iNOS）、神经型NO合成酶（nNOS）、碱性成纤维细胞生长因子（bFGF）、转化生长因子B（TGFl3）基因表达的调控作用。方法眼罩遮盖法建立豚鼠近视眼模型,酶消化法原代培养其视网膜Müller细胞,GFAP免疫组织化学染色进行细胞鉴定。根据干预因素不同,把Müler细胞分为正常对照组、近视组、近视＋GF109203X组、近视＋PMA组和近视＋DMSO组。RT—PCR检测TH、iNOS、nNOS、bFGF和TGFβmRNA的表达情况。结果与正常对照组比较,近视眼视网膜Mtiller细胞iNOS、nNOS、bFGF和TGFβmRNA表达上调,THmRNA表达下调（P〈0．05）。PKC激活剂（PMA）激活PKC后,近视眼视网膜Müller细胞表达nNOS、iNOS、TH和bFGFmRNA上调（P〈0．05）;GF109203X抑制PKC活性后,这些因子的mRNA表达下调（P〈n05）。结论豚鼠近视眼视网膜Müller细胞nNOS、iNOS、bFGF和TH基因的表达受PKC调控,Müller细胞可能为近视信号因子的一个重要来源。     

人参皂苷Rg3对高糖下视网膜血管内皮细胞增殖及ICAM-1表达的影响

目的:研究人参皂苷Rg3对体外培养的高糖条件下人视网膜血管内皮细胞(human retinal capillary endothelial cell,HRCEC)增殖与细胞间黏附分子-1(intercellular adhesionmolecule-1,ICAM-1)表达的影响。方法:体外培养从角膜移植术后新鲜人眼球提取的HRCECs。取生长良好的第3~4代细胞用于实验,实验分为低糖对照组、高糖对照组、高糖+不同浓度Rg3组,用噻唑蓝(MTT)比色法检测HRCEC的增殖。通过免疫细胞化学法观察各分组HRCEC ICAM-1的表达情况。结果:MTT比色法结果显示,高糖对照组与低糖对照组没有显著差异(P>0.05),用10,20,40,80,160mg/L的人参皂苷Rg3处理高糖下HRCEC24,48,72h与高糖对照组相比具有显著性差异(P<0.05),高糖+不同浓度Rg3组之间呈时间和浓度的显著性差异(P<0.05)。免疫细胞化学检测显示,与低糖对照组相比,高糖对照组ICAM-1表达明显(P<0.05),用40,80,160mg/L的人参皂苷Rg3处理高糖下HRCEC48h与高糖对照组相比ICAM-1表达有显著性差异(P<0.05),高糖+不同浓度Rg3组之间两两比较均具有显著性差异(P<0.05)。结论:人参皂苷Rg3可抑制高糖下视网膜血管内皮细胞增殖和ICAM-1表达。     

色素上皮衍生因子对糖尿病大鼠视网膜谷氨酰胺合成酶表达的影响

目的　观察色素上皮衍生因子（PEDF）对糖尿病大鼠视网膜Müller细胞谷氨酰胺合成酶（GS）表达的影响。方法　将Sprague-Dawley大鼠分为模型组、模型对照组、PEDF干预组（干预组）、干预对照组,每组均为8只大鼠。模型组、干预组、干预对照组大鼠链脲佐菌素诱导糖尿病大鼠模型。模型组大鼠不作任何干预,模型对照组为相同月龄的正常大鼠,干预组大鼠左眼玻璃体腔注射0.1 μg/μl的PEDF 10 μl,干预对照组大鼠左眼玻璃体腔注射相同容积的磷酸盐缓冲液。采用免疫组织化学法和实时荧光聚合酶链反应（PCR）法检测视网膜GS和白细胞介素-1β（IL-1β）的表达变化。将视网膜Müller细胞置于高糖环境下培养,实验干预组中加入100 ng/ml PEDF,空白对照组加入相同容积的培养液,24 h后通过蛋白质免疫印迹（Western blot）法和实时荧光PCR法检测PEDF对Müller细胞GS和IL-1β表达的改变。流式细胞仪锚定蛋白-异硫氰酸荧光素和碘化丙啶（Annexin V-FITC-PI）双染色法检测100ng/mlPEDF对高糖状态下Müller细胞凋亡的影响。结果　实时荧光PCR法从基因水平和免疫组织化学法从蛋白质水平检测均显示,相对于模型对照组大鼠,模型组大鼠视网膜GS表达降低,而IL-1β的表达升高,实时荧光PCR法：GS: t=4.23, P＜0.01;IL-1β: t=16.73,P＜0.01;免疫组织化学法：GS:t=5.13,P＜0.01;IL-1β: t=9.32, P＜0.01;干预组大鼠玻璃体腔注射PEDF 48 h后,IL-1β的表达下降,GS的表达升高,与干预对照组比较,实时荧光PCR法：GS: t=3.87,P＜0.01;IL-1β: t=3.61,P＜0.05;免疫组织化学法：GS:t=3.32, P＜0.05;IL-1β: t=2.63, P＜0.05。在高糖环境下,通过实时荧光PCR法和Western bot 法检测均显示PEDF可以下调IL-1β的表达,而上调GS的表达,与空白对照组比较,实时荧光PCR法：GS: t=2.89, P＜0.05;IL-1β: t=3.37, P＜0.05;Western blot：GS: t=2.66, P＜0.05;IL-1β: t=3.23, P＜0.05。流式细胞仪检测结果显示,PEDF可以抑制高糖环境下Müller细胞的凋亡,实验组凋亡率与空白对照组凋亡率比较,差异有统计学意义(t=3.21,P＜0.05)。结论　对于糖尿病大鼠,PEDF可能通过下调视网膜Müller细胞中IL-1β的表达来上调GS的表达,从而改善谷氨酸循环,抑制神经节细胞的死亡      

A novel co-culture model of the blood-retinal barrier based on primary retinal endothelial cells, pericytes and astrocytes

Loss of blood-retinal barrier (BRB) properties is an important feature in the pathology of diabetic macular edema (DME), but cellular mechanisms underlying BRB dysfunction are poorly understood. Therefore, we developed and characterized a novel in?vitro BRB model, based on primary bovine retinal endothelial cells (BRECs). These cells were shown to maintain specific in?vivo BRB properties by expressing high levels of the endothelial junction proteins occludin, claudin-5, VE-cadherin and ZO-1 at cell borders, and the specific pumps glucose transporter-1 (GLUT1) and efflux transporter P-glycoprotein (MDR1). To investigate the influence of pericytes and astrocytes on BRB maintenance in?vitro, we compared five different co-culture BRB models, based on BRECs, bovine retinal pericytes (BRPCs) and rat glial cells. Co-cultures of BRECs with BRPCs and glial cells showed the highest trans-endothelial resistance (TEER) as well as decreased permeability of tracers after vascular endothelial growth factor (VEGF) stimulation, suggesting a major role for these cell types in maintaining barrier properties. To mimic the in?vivo situation of DME, we stimulated BRECs with VEGF, which downregulated MDR1 and GLUT1 mRNA levels, transiently reduced expression levels of endothelial junctional proteins and altered their organization, increased the number of intercellular gaps in BRECs monolayers and influence the permeability of the model to differently-sized molecular tracers. Moreover, as has been shown in?vivo, expression of plasmalemma vesicle-associated protein (PLVAP) was increased in endothelial cells in the presence of VEGF. This in?vitro model is the first co-culture model of the BRB that mimicks in?vivo VEGF-dependent changes occurring in DME.     

白藜芦醇对高糖环境下视网膜血管内皮细胞增殖及HMGB1乙酰化的影响

目的：探讨白藜芦醇对高糖环境下视网膜血管内皮细胞增殖的影响,并对其机制进行探讨。

方法：人视网膜血管内皮细胞培养于低糖或高糖环境,通过MTT法测定各组细胞增殖,研究白藜芦醇对高糖培养的视网膜血管内皮细胞增殖的影响。通过Western-blot及免疫共沉淀检测SIRT1表达及HMGB1的乙酰化。

结果：白藜芦醇对高糖环境下的视网膜血管内皮细胞增殖具有显著抑制作用(P<0.05),且随白藜芦醇剂量增加,抑制作用增强。高糖抑制SIRT1表达,提高HMGB1的乙酰化,白藜芦醇能逆转上述改变。

结论：白藜芦醇可能通过SIRT1-HMGB1通路抑制高糖环境下的视网膜血管内皮细胞增殖。