巴曲酶对视网膜色素上皮细胞增生活性的影响

目的探讨巴曲酶对视网膜色素上皮细胞(retinal pigment epithelium,RPE)增生活性的影响。方法利用体外培养的RPE细胞系,应用噻唑兰比色法观察不同浓度的巴曲酶对RPE增生活性的影响。结果当巴曲酶浓度不大于1/10KU.mL-1时各浓度巴曲酶组(1/100KU.mL-1、1/32KU.mL-1、1/16KU.mL-1、1/10KU.mL-1)与对照组吸光度(optical density,OD)值差异无统计学意义(P=0.068、0.455、0.675、0.159);巴曲酶浓度为1/8KU.mL-1时OD值明显降低(P=0.000)。OD值与培养液渗透压呈明确的负相关(r=-0.951,P=0.000);巴曲酶组和等渗对照组OD值的差异没有统计学意义(P=0.749)。结论渗透压符合RPE生长要求的前提下,巴曲酶对体外培养的RPE增生无明显影响,其应用于玻璃体手术中控制眼内出血的可行性值得进一步研究。     

Nitric oxide as a second messenger in phagocytosis by cultured retinal pigment epithelial cells

PURPOSE: To investigate a possible role of the nitric oxide (NO)-cGMP signal transduction system in phagocytosis of rod outer segments (ROS) by cultured retinal pigment epithelial (RPE) cells. METHODS: Primary cultures of RPE cells from 10-day-old Brown Norway rats were used to study the phagocytosis of ROS by these cells. Phagocytosis of ROS was evaluated with or without an inhibitor of nitric oxide synthase (NOS), N(G)-nitro-L-arginine (L-NNA), and the reverse effects of L-NNA by L-arginine and 8-bromo-cGMP on phagocytosis were also studied. NO-associated cGMP production by RPE cells was monitored during phagocytosis using L-NNA. NOS activity was assayed in RPE cells and ROS to locate the source of NO. RESULTS: Phagocytosis of ROS was inhibited by L-NNA but not by D-NNA. L-NNA inhibited the ingestion in a dose-dependent manner, but not the binding of ROS. The inhibition was reversed by L-arginine and also by an NO donor, SIN-1. RPE cells challenged with ROS showed increased cGMP activity, which was significantly reduced by L-NNA and again restored by an overdose of L-arginine. NOS activity was found in RPE cells but not in ROS. CONCLUSIONS: Our data show that cGMP plays a role in the ingestion phase of ROS phagocytosis by RPE cells via a cGMP second-messenger system.     

Growth of cultured porcine retinal pigment epithelial cells

PURPOSE: To establish and characterize cultures of porcine retinal pigment epithelial (pRPE) cells in order to produce confluent monolayers of cells for transplantation. METHODS: Primary pRPE cell cultures were established. Cell morphology was assessed by phase contrast and electron microscopy. Growth was determined by the crystal violet dye uptake assay. DNA synthesis and content were measured by incorporation of 3H-thymidine and flow cytometry. RESULTS: This primary culture resulted in cells with well-preserved morphology that could be propagated in up to six passages. The deterioration observed over time in cultures was not due to a constant high rate of cell turnover as postconfluency cell proliferation was limited. However, a large fraction of the cells had a high DNA content despite a lack of active DNA synthesis. CONCLUSIONS: The present method yields pRPE cells of high purity and proliferative capacity with preserved epithelial phenotype. However, aberrant DNA profiles and the deterioration of cell morphology observed over time in this graft material represent serious problems in RPE transplantation.     

Adrenomedullin in cultured human retinal pigment epithelial cells

PURPOSE: To determine whether adrenomedullin (ADM), a vasorelaxant peptide is produced and secreted by human retinal pigment epithelial (RPE) cells, whether ADM expression is regulated by inflammatory cytokines and a growth factor, and whether ADM has proliferative effects on these cells. METHODS: Production and secretion of ADM by cultured human RPE cells were examined by Northern blot analysis and radioimmunoassay. Regulation of the ADM expression by basic fibroblast growth factor, interferon (IFN)-gamma, tumor necrosis factor-alpha, interleukin (IL)1beta, or all-trans-retinoic acid was studied. In addition, proliferative effects of ADM on human RPE cells were examined by modified 3-(4,5-dimetylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: ADM mRNA was expressed constitutively in all three human RPE cell lines (F-0202, D407, and ARPE-19) examined. Immunoreactive ADM was detected in the cultured media by radioimmunoassay. Sephadex G-50 column chromatography of the cultured medium showed a single peak eluting in the position of ADM-(1-52). Treatment with IFN-gamma or IL-beta increased ADM mRNA levels and immunoreactive-ADM levels in the medium in dose- and time-dependent manners in ARPE-19 cells. Exogenously added ADM increased the number of F-0202 cells and ARPE-19 cells, and the treatment with ADM antibody or ADM-(22-52) (an ADM antagonist) decreased it. CONCLUSIONS: Human RPE cells produced and secreted ADM. IFN-gamma and IL-1beta induced ADM expression in ARPE-19 cells. Furthermore, ADM stimulated proliferation of RPE cells. These results raise the possibility that ADM is related to the pathophysiology of some inflammatory and proliferative ocular diseases.     

Effects of phenothiazines on cultured retinal pigment epithelial cells

Phenothiazines (chlorpromazine, trifluoperazine, prochlorperazine, and fluphenazine) showed dose-dependent inhibition of phagocytosis of latex particles by cultured chick retinal pigment epithelial cells at concentrations of 10(-5)-10(-14) mol/l. Calmodulin antagonists (W-5, W-7, W-12, and W-13) showed similar effects as phenothiazines at concentrations of 10(-5)-10(-14) mol/l. These reactions were partially reversible at a concentration of 10(-9) mol/l. Cells cultured for 3 days in the presence of 10(-5) mol/l chlorpromazine or 10(-5) mol/l W-7 demonstrated morphologic alterations in their microvilli which were similar to those seen after cytochalasin B treatment, i.e., thinning and elongation of the microvilli with honeycomb-like changes.     

Oxidant-induced apoptosis in cultured human retinal pigment epithelial cells

PURPOSE: To determine the mechanism of oxidant-induced cell death in cultured human retinal pigment epithelium (hRPE). METHODS: Cultured hRPE cells were treated with different concentrations of a chemical oxidant, t-butylhydroperoxide (tBH), for different periods of time. Apoptosis was determined with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) and flow cytometry. Mitochondrial membrane potential (mtdelta psi) was measured by rhodamine 123 staining and subsequent flow cytometry. Release of mitochondrial cytochrome c (cyt c) and cleavage of procaspase 3 and caspase substrates were determined by western blot analysis. RESULTS: t-Butylhydroperoxide caused time- and dose-dependent activation of apoptosis in hRPE, indicated by characteristic morphologic changes; TUNEL-positive labeling; phosphatidylserine (PS) exposure; and procaspase 3, poly(ADP-ribose)polymerase, lamin, and tubulin cleavage. An early decrease of mtdelta psi was observed before caspase activation, together with the release of mitochondrial cyt c. CONCLUSIONS: Results indicate that tBH can induce apoptosis in hRPE, probably by triggering the mitochondrial permeability transition, which results in swelling and release of mitochondrial intermembrane proteins.     

Cytomegalovirus replication in cultured human retinal pigment epithelial cells

Retinal pigment epithelium (RPE) was isolated from the globe of a donor positive for human immunodeficiency virus (HIV) who had cytomegalovirus (CMV) retinitis secondary to acquired immunodeficiency syndrome (AIDS). In culture, the cells exhibited normal epithelioid morphology by phase contrast microscopy. After two weeks the cells developed cytomegaly and dense intranuclear and cytoplasmic inclusions and, eventually, died. Transmission electron microscopy (EM) demonstrated intranuclear nonenveloped virus particles 80-120 nm in diameter consistent with a herpes type infection. Immunofluorescence staining demonstrated the presence of CMV antigens. Conditioned medium from the infected cells caused infection in RPE cells isolated from normal donors. Hybridization assay demonstrated the presence of CMV DNA and indicated that the time course of the infection was similar, but not identical to infection in MRC-5 and HEL cells. We conclude that cultured human RPE is a permissive host for CMV.     

Characteristics of iris and retinal pigment epithelial cells cultured on collagen type I membranes

PURPOSE: Transplantation of pigment epithelial cells is a promising treatment modality to repair retinal damage in age-related macular degeneration. For this purpose, it is necessary to establish cell culture techniques that allow acquisition of proper functional and morphological characteristics by the cells to be transplanted. METHODS: Primary retinal pigment epithelial (RPE) and iris pigment epithelial (IPE) cells grown to confluence on collagen membranes were examined for morphology, adhesion, proliferation, apoptosis, as well as viability after ex vivo transplantation. RESULTS: Pigment epithelial cells adhere, proliferate, form monolayers, acquire differentiated properties, and remain viable during transplantation to the subretinal space. CONCLUSIONS: Pigment epithelial cells cultured on collagen membranes acquire differentiated characteristics and are amenable to be transplanted as cell monolayers.     

Characterization of retinal pigment epithelial cells cultured on microporous filters

Retinal pigment epithelium (RPE) cultured on microporous filter supports was compared to RPE cultured on plastic and evaluated for features characteristic of RPE in vivo. RPE cells grown on filters were cuboidal, formed junctional complex structures between cells, and had elaborate microvilli and basal infoldings similar to RPE in vivo, while RPE grown on plastic also formed intercellular junctions but appeared squamous and had few microvilli and basal infoldings. RPE grown on filters or plastic secreted an extracellular matrix at the basal surface and ingested isolated rat rod outer segments at the apical surface. RPE grown on filters coated with laminin or fibronectin became confluent more rapidly than RPE grown on uncoated filters, while RPE grown at the same density on filters coated with collagen type I did not become confluent. The laminin and fibronectin coatings did not alter the RPE cell morphology; however, cells seeded on collagen-coated filters grew in large disorganized clusters. RPE grown on laminin-coated filters formed functional tight junctions as evidenced by the capacity of RPE monolayers to prevent the bulk flow of medium and the passage of trypan blue across the filter. Radiolabeled sucrose and inulin were used to measure the paracellular flux through the tight junctions between cells. The passage of these tracers was linear over time, with the lower molecular weight tracer, sucrose, passing through the monolayer more readily than inulin. Values for the flux of radiolabeled bovine serum albumin across RPE monolayers fell between values for sucrose and inulin. The results from these studies show that RPE monolayers cultured on laminin-coated filters maintain a morphology similar to that of RPE in vivo, are capable of ingesting rod outer segments, and form a selectively permeable barrier to various tracers. This culture system should be useful for studies of transepithelial transport, secretion, endocytosis and exocytosis that require independent control of the extracellular environment at the apical and basolateral cell surfaces.     

凝血酶对体外培养的视网膜色素上皮细胞生长的影响

目的 探讨凝血酶对视网膜色素上皮细胞的影响。方法 利用体外培养的视网膜色素上皮细胞，观察不同浓度的凝血酶对视网膜色素上皮细胞的影响。结果 各浓度的凝血酶对体外培养的视网膜色素上皮细胞具有促进增殖的作用。且40U/ml尤为明显。结论 凝血酶对体外培养的视网膜色素上皮细胞具有促进增殖的作用。这为探讨增生性玻璃体视网膜病变的提供了实验依据。     

体外培养的猪眼色素上皮细胞屏障功能的研究

目的 研究体外培养的猪眼视网膜色素上皮（RPE）细胞的血视网膜外屏障功能。 方法 对猪眼RPE细胞进行原代培养，第3代细胞接种于微孔滤器，微孔滤器的滤膜为无聚乙烯吡咯酮（PVP）聚碳酸脂膜（polycarbonate），分别于培养1、2、3、4周对滤膜表面行光学显微镜观察，于培养后2周对膜切面行光学显微镜和透射电子显微镜观察;行跨膜电阻测定并用荧光素钠和辣根过氧化物酶（HRP）进行通透性检测。 结果 成功原代培养了猪眼RPE细胞。光学显微镜观察结果显示，RPE细胞接种1周后，细胞基本汇合，接种后2、3周时RPE细胞密度无明显变化，接种后4周时细胞密度下降;滤膜及细胞标本切面观察结果显示，RPE细胞可在滤膜表面表现出单层有极性生长的特性;接种于微孔滤器2周后，RPE细胞跨上皮细胞电阻达（97.44±11.36） Ω/cm2，并至少持续到接种后3周;通透性检测结果显示，孵育30 min后只有0.27%的荧光素钠和0.17%的HRP从滤膜上方到达下方，分子量小的荧光素钠比分子量大的HRP通透率高。 结论 应用无PVP聚碳酸脂膜的微孔滤器可以建立体外RPE细胞有极性单层生长的模型，并用于屏障功能的研究。 (中华眼底病杂志, 2006, 22: 188-191)     

金雀异黄素对培养人视网膜色素上皮细胞增生的抑制作用

目的观察金雀异黄素对培养人视网膜色素上皮(hRPE)细胞增生的影响.方法通过MTT比色法和核仁嗜银蛋白染色分析,观察金雀异黄素对hRPE增生的影响.结果不同浓度的金雀异黄素可以抑制hRPE增生,在25～100mg·L-1的范围内呈剂量效应关系,抑制率为12.0%～64.6%(P＜0.05);并随时间的延长,抑制效应增强.嗜银蛋白染色结果50mg·L-1金雀异黄素作用12h即有胞核内AgNORs的减少,平均数为2.7(P=0.034),25mg·L-1金雀异黄素作用24h后,其胞核内AgNORs的数量平均为3.9(P=0.023).并随剂量的增加和时间的延长,胞核内AgNORs的数量减少.结论不同浓度的金雀异黄素作用于培养hRPE细胞,抑制hRPE细胞的增生,有剂量和时间效应关系,随剂量增加和时间延长,抑制作用越明显.提示金雀异黄素可以为增生性玻璃体视网膜病变的机理和防治研究提供新的思路.     

缺氧诱导体外培养人视网膜色素上皮细胞凋亡鲻

目的:了解缺氧条件下体外培养人视网膜色素上皮 (retinal pigment epithelium,RPE)细胞的凋亡情况.方法:将培养的人RPE细胞置于含10mL/L O2、50mL/L CO2和940mL/L N2的培养箱内建立缺氧模型.于缺氧后1,3,6,12,24h,利用扫描电镜、透射电镜、脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal-deoxynucleotidyl transferase mediated nick end labeling,TUNEL)技术和流式细胞仪测定RPE细胞凋亡水平.结果:常氧状态下RPE细胞生长良好,几乎没有凋亡(TUNEL法测凋亡指数为1.2).缺氧条件下,RPE细胞发生了不同程度的凋亡,缺氧后3h凋亡水平达峰值(凋亡指数为34.43).结论:缺氧可导致体外培养的人RPE细胞凋亡,提示RPE凋亡可能参与了某些缺血缺氧性眼病的发生.     

蓝光诱导体外培养的人视网膜色素上皮细胞凋亡

目的 观察蓝光光照对体外培养的人视网膜色素上皮（RPE）细胞凋亡的影响。 方法 用蓝光照射体外培养的人RPE细胞，分为3组，A组：不同光照强度；B组：同一光照强度，不同光照时间；C组：同一光照强度和光照时间，不同细胞培养终止时间。利用末端脱氧核酸转移酶介导的原位缺口末端标记（TUNEL）、荧光素标记的连接素V/碘化吡啶（Annexin V-FITC/PI）双染流式细胞检测、透射电子显微镜等手段观察细胞凋亡。 结果 TUNEL染色阳性细胞的体积缩小变圆，细胞核浓缩，边聚成新月形或帽状，细胞核碎裂成数个，细胞膜出胞。透射电子显微镜观察发现细胞内线粒体肿胀，线粒体内膜嵴消失；粗面内质网扩张；溶酶体增加，内含代谢产物。A组低于一定阈值［（500±100）lx］的蓝光光照对RPE细胞损伤较轻，细胞凋亡及坏死随光照强度的增强而增加；B组随着光照时间延长，RPE细胞凋亡数量没有增加，而细胞坏死逐渐增加；C组光照后6、12h，损伤以细胞凋亡为主，但随着光照时间延长，凋亡继发坏死细胞和坏死细胞明显增加。 结论 蓝光照射可引起体外培养的人RPE细胞损伤，损伤形式有凋亡、凋亡继发坏死及坏死；损伤程度呈光照强度和光照时间依赖性。 (中华眼底病杂志, 2005, 21: 384-387)     

缺氧诱导体外培养人视网膜色素上皮细胞凋亡

目的:了解缺氧条件下体外培养人视网膜色素上皮(retinal pigment epithelium,RPE)细胞的凋亡情况。方法:将培养的人RPE细胞置于含10mL/LO2、50mL/LCO2和940mL/LN2的培养箱内建立缺氧模型。于缺氧后1,3,6,12,24h,利用扫描电镜、透射电镜、脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal-deoxynucle-otidyl transferase mediated nick end labeling,TUNEL)技术和流式细胞仪测定RPE细胞凋亡水平。结果:常氧状态下RPE细胞生长良好,几乎没有凋亡(TUNEL法测凋亡指数为1.2)。缺氧条件下,RPE细胞发生了不同程度的凋亡,缺氧后3h凋亡水平达峰值(凋亡指数为34.43)。结论:缺氧可导致体外培养的人RPE细胞凋亡,提示RPE凋亡可能参与了某些缺血缺氧性眼病的发生。     

Induction of adrenomedullin by hypoxia in cultured retinal pigment epithelial cells

PURPOSE: To explore the effects of hypoxia on the production and secretion of adrenomedullin (ADM) and endothelin (ET)-1 in human retinal pigment epithelial (RPE) cells. METHODS: RPE cells were cultured under normoxic or hypoxic (1% O2) conditions. Expression of ADM and ET-1 was examined by Northern blot analysis and radioimmunoassay. Effects of ADM and ET-1 on the number of RPE cells were examined by modified 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: ADM mRNA expression levels and immunoreactive ADM levels in the medium were increased by hypoxia in all three human RPE cell lines (ARPE-19, D407, and F-0202). Immunoreactive ET was detected in the cultured media of D407 cells and ARPE-19 cells and identified as ET-1 by reversed-phase high performance liquid chromatography. Hypoxia treatment for 48 hours increased immunoreactive ET levels approximately 1.3-fold in the cultured media of D407, but not ARPE-19 cells. Hypoxia decreased the number of ARPE-19 cells and F-0202 cells, and the treatment with ADM ameliorated the hypoxia-induced decrease in the cell number. In contrast, exogenously added ET-1 had no significant effects on the number of ARPE-19 cells under normoxia and hypoxia. CONCLUSIONS: Hypoxia increased the expression of ADM in all three human RPE cell lines, whereas the induction of ET-1 by hypoxia was found only in D407 cells. ADM induced by hypoxia may have protective roles against hypoxic cell damage in RPE cells.     

上皮生长因子在家兔视网膜色素上皮细胞培养中的作用

本研究对有色家兔视网膜色素上皮（ＲＰＥ）细胞进行体外培养，结果显示：低浓度上皮生长因子ＥＧＦ对ＲＰＥ细胞无刺激作用，而达到适当浓度时对ＲＰＥ细胞有明显刺激作用，但高浓度与适当浓度的作用相同。本文认为适当浓度的ＥＧＦ可促进ＲＰＥ培养细胞生长，缩短传代周期，细胞增殖速度快，细胞数量明显增多，且细胞形态不受影响。ＥＧＦ对体外培养ＲＰＥ细胞的最佳浓度为１０ｎｇ／ｍｌ，这为在体外大量培养ＲＰＥ细胞提供了新的实验数据     

Dispersion of retinal pigment epithelial cells from experimental retinal holes

The effects of cryotherapy, transcleral massage, or directed irrigation on exposed retinal pigment epithelial (RPE) cells at the base of an experimental retinal hole were studied in living rabbit eyes. Cryotherpy or massage with or without vitrectomy failed to release RPE cells or result in preretinal membrane formation. Directed irrigation dispersed viable RPE cells into the vitreous and produced cellular precipitates with membranes on the inferior retina, although the membranes tended to regress within 6 weeks after surgery. These results suggest that healthy RPE cells at the base of retinal tears are not easily released into the vitreous and may not contribute to the formation of preretinal membranes found in proliferative vitreoretinopathy.This work was supported in part by a grant from MedChem Products, Woburn, Mass