体外培养的成年兔眼色素上皮细胞屏障功能的研究

目的 研究体外培养的成年兔眼视网膜色素上皮(retinal pigment epithelial,RPE)细胞的血-视网膜外屏障功能.方法 对成年兔眼RPE 细胞进行原代培养,免疫组织化学通过MNF116和S-100鉴定细胞纯度.将细胞接种于铺有层粘连蛋白的Transwell滤膜上,分别于培养过程中不同时间点进行跨膜电阻测定,待电阻达到平台期后对膜切面行透射电子显微镜观察;并通过细胞ZO-1免疫荧光化学法了解紧密连接的形成情况.结果 成功原代培养了兔眼RPE 细胞并且无其他细胞污染.接种于Transwell后,RPE 细胞TER值3周达到最高值约88.14 Ω·cm2,维持1周并开始下降.透射电镜可见细胞表面有大量微绒毛并形成紧密连接.ZO-1免疫荧光化学结果可见细胞形态基本呈多边形,紧密连接基本形成.结论 成年兔眼RPE细胞通过培养于铺有层粘连蛋白的Transwell滤膜上可以成功建立细胞屏障功能模型.     

曲安奈德对人视网膜色素上皮细胞活性与 屏障功能的影响

目的观察曲安奈德 (TA)对人视网膜色素上皮（RPE）细胞活性与屏障功能的影响。方法用ARPE-19细胞，96孔板中培养至４周，加入不同浓度的TA（0.02、0.05 mg/ml），继续培养3 d或7 d，四甲基偶氮唑盐比色法（MTT）检测细胞活性；将细胞培养在多聚酯滤膜上，４周时记录跨上皮电阻（TER），然后分别在培养液中加入0.02、0.05 mg/ml TA继续培养１周，再次测量TER，并以辣根过氧化物酶（HRP）作示踪剂、酶联免疫吸附试验（ELISA）法评价不同浓度TA组ARPE-19细胞的通透性。结果在含0.02 mg/ml TA培养液中培养3 d或7 d，细胞平均存活率分别为93.70%和90.63%，其细胞活性与对照组相比，差异无统计学意义（P=0.147，0.091）；在含0.05 mg/ml TA培养液中培养相同时间后，细胞活性较对照组显著降低（平均存活率为87.75%、88.98%；P=0.025，0.043）；经过1周培养，2个处理组的TER与对照组相比均有极显著降低（P 均＜0.001）；两个处理组HRP的通透性均显著高于对照组（0.001＜P＜0.05）。结论TA可以使ARPE 19细胞的活性降低，并破坏其屏障功能的完整性。(中华眼底病杂志,2005,21:237-239)      

豚鼠形觉剥夺性近视眼视网膜、脉络膜多巴胺代谢的变化

目的研究形觉剥夺对豚鼠神经视网膜、视网膜色素上皮（retinal pigment epithelium,RPE）／脉络膜复合体多巴胺（dopamine,DA）代谢的影响。方法28日龄豚鼠36只,分为3组：正常对照组、遮盖组、遮盖＋去遮盖组,每组12只。遮盖组用半透明眼罩遮盖豚鼠右眼14d,遮盖＋去遮盖纽在遮盖11d后去遮盖3d。14d后测定角膜曲率半径、眼球屈光度和眼轴长度。处死豚鼠,取眼后极部视网膜、脉络膜组织,用免疫组化染色和Western blotting法检测酪氨酸羟化酶（tyrosine hydroxylase,TH）蛋白在神经视网膜、RPE／脉络膜复合体的表达情况,用高效液相色谱检测神经视网膜、RPE／脉络膜复合体的DA、二羟基苯乙酸（3,4-dihydroxyphenylacetic acid,DOPAC）的含量。结果TH蛋白阳性表达于视网膜神经节细胞和内核层部分细胞,RPE／脉络膜复合体中表达阴性。遮盖14d后,豚鼠遮盖眼眼轴延长,近视形成,神经视网膜TH蛋白表达量和DA、DOPAC含量降低（P〈0．05）。遮盖＋去遮盖纽的遮盖眼近视程度低于遮盖组．其神经视网膜TH蛋白表达量和DA、DOPAC含量升高（P〈O．05）,但仍低于正常对照组（P〈O．05）。各纽豚鼠RPE／脉络膜复合体的DA、DOPAC含量比较,差异无统计学意义（P〉0．05）。结论形觉剥夺能调控豚鼠神经视网膜DA代谢,但不影响RPE／脉络膜复合体的DA代谢。     

肝细胞生长因子诱导实验性视网膜脱离的病理机制研究

目的 观察肝细胞生长因子（HGF）对视网膜色素上皮（RPE）细胞屏障功能的影响以及RPE内过度表达HGF导致视网膜脱离（RD）的病理机制。 方法 编码HGF（AdCMV.HGF）、绿色荧光蛋白（Ad CMV.GFP）的E1/E3缺失的腺病毒载体，以5×10⁴ 噬斑形成单位（pfu）/眼注射到成年有色兔的视网膜下。检查注射后3、7、14、28 d时的眼底及组织病理变化,利用免疫组织化学和酶联免疫吸附试验（ELISA）方法检测HGF在视网膜和玻璃体的表达水平。 结果 对照组注射Ad CMV.GFP眼显示GFP几乎仅表达于PRE单核细胞层，AdCMV.HGF注射眼在注射点处的PRE细胞出现强的HGF免疫阳性反应。玻璃体内HGF的表达水平在注射7 d后达到最高峰、28 d后降低到基础水平。在HGF的表达期内AdCMV.HGF注射眼出现慢性RD和脉络膜慢性炎症。在RD区域，视网膜下的空间内可见增生性的RPE细胞，部分实验兔眼还产生多层的细胞膜结构。 结论 RPE内过度表达的HGF能引发慢性浆液性RD，同时伴有视网膜下RPE增生。提示HGF可能作为治疗RD的作用靶点。(中华眼底病杂志，2007，23：193-197)     

血-视网膜外屏障发育的研究现状

血-视网膜外屏障(BRB)由视网膜色素上皮(RPE)细胞间的连续网状紧密连接构成,是维持视网膜及视觉生理状态的重要基础.BRB由视神经管的膨出部分视泡发育而来,随着胚胎发育逐渐形成.发育过程中紧密连接复合体的结构及分子组成均发生了改变,且受周围组织的调控.BRB的发育具有种属差异.干细胞来源的RPE细胞有可能成为研究RPE屏障功能的最佳模型.     

视黄酸对豚鼠离焦性近视眼视网膜色素上皮通透性的调控

背景视网膜视黄酸在离焦性近视形成中起重要作用,但目前尚不清楚其如何通过视网膜色素上皮（RPE）屏障向脉络膜传递近视信号。目的研究全反式视黄酸（atRA）对离焦性近视眼RPE屏障功能的影响。方法21日龄清洁级三色豚鼠30只,用随机数字表法分为正常对照组和离焦组,一6D凹透镜缝合于离焦组豚鼠左眼15d以制备离焦性近视模型,每天光照与黑暗周期为12h／12h。用角膜曲率计测量各组豚鼠的角膜曲率半径,行复方托吡卡胺滴眼液扩瞳检影验光以测量豚鼠眼球屈光度,应用A型超声法测量各组豚鼠的眼轴长度。于造模15d时处死动物并分离视网膜,体外培养RPE细胞并传代,将第3代RPE细胞用于实验,制备视网膜铺片,接种于Millcell—PET微孔滤膜插入式培养池,分别加入1×10-6、1×10-7、1×10-8和1×10-9mol／LatRA培养RPE细胞24h,以加入等体积atRA溶剂的培养孔作为阴性对照,以完全培养基加MTT溶液的无细胞孔作为空白对照。采用MTT比色法检测各组RPE细胞的存活率,用CN10一EVOM2型电阻测量仪测定单层细胞跨上皮电阻（TER）,计算RPE细胞的TER值,采用FM1-43型荧光染色技术检测得出RPE细胞FM1-43阳性荧光染色的相对强度值,评价RPE细胞膜泡运输变化。结果豚鼠模型眼屈光度为（-2．20±O．95）D,对照组为（＋1．15±0．30）D,差异有统计学意义（t=14．57,P〈0．01）;豚鼠模型眼的眼轴长度为（8．24±0．09）mm,明显长于对照组的（7．81±0．05）mm,差异有统计学意义（t=17．20,P〈0．01）。原代培养豚鼠近视眼的RPE细胞,取第3代细胞用于实验。RPE细胞接种于Millcell培养池1周后细胞长满滤膜,呈单层生长。加入atRA干预24h,RPE细胞的存活率随药物浓度的升高而逐渐降低,1×10^-9 mol／LatRA组RPE细胞存活率为93．3％,1×10-8mol／LatRA组为88．2％,1×10-6mol／LatRA组和1×10-7mol／LatRA组的RPE细胞大量死亡。不同浓度atRA组RPE细胞的TER值和RPE细胞FMl_43阳性荧光染色的相对强度值的总体比较差异均有统计学意义（F：43．89,P=0．00;F=26．13,P=0．00）,其中1×10-mo[／LatRA组RPE细胞的TER值为（107．32±9．58）Ω）／cm2,荧光染色强度为55．29±9．79,均明显高于1×10-、1×10-、1×10-mol／LatRA组,差异均有统计学意义（P〈0．05）,FMl_43荧光染色部位主要在RPE细胞的细胞膜和细胞质。结论AtRA能够通过增加豚鼠近视眼RPE的紧密连接功能及膜泡运输改变RPE细胞的屏障功能。     

高血压大鼠视网膜色素上皮细胞超微结构及其屏障功能观察

目的 观察高血压大鼠视网膜色素上皮(retinal pigment epithelium,RPE)细胞超微结构的改变及其屏障功能受损情况，探讨其与神经视网膜病变的关系。方法 用胶体镧示踪结合透射电镜观察5、6、7个月龄自发性高血压大鼠RPE细胞超微结构改变及脉络膜视网膜屏障渗透性的改变，并与同月龄正常京都种大鼠作对照。结果 ①高血压大鼠RPE细胞中线粒体肿胀，内质网扩张，基底部皱褶减少，微绒毛变稀疏。这些退行性改变随鼠龄增大与血压的增高而加重。②6、7个月龄大鼠脉络膜视网膜屏障破坏，脉络膜毛细血管中的胶体镧进入到RPE细胞内褶及细胞间隙，且能通过紧密连接到达细胞顶部进入视网膜下间隙，而5个月龄高血压大鼠及各种正常大鼠、胶体镧不能通过此屏障，仅到达RPE细胞之间。结论 高血压大鼠视网膜病变的早期RPE细胞已有缺血、缺氧所致的退行性改变，且伴有脉络膜视网膜屏障的渗透性增加。     

体外内层血视网膜屏障模型中Müller胶质细胞对紧密连接的影响

目的:建立体外内层血视网膜屏障(iBRB)模型并研究视网膜Müller胶质细胞(RMGC)对紧密连接(TJ)的影响。方法:采用免疫磁珠方法原代纯化和培养大鼠视网膜微血管内皮细胞(RMEC),采用改良酶消化方法培养RMGC,RMEC和RMGC在微孔膜的两侧共培养建立iBRB模型,通过相差显微镜和透射电子显微镜(TEM)观察两种细胞的生长和TJ的形态。采用跨内皮细胞电阻(TER)测量和TJ相关蛋白ZO-1荧光染色和蛋白电泳来评价TJ的变化情况。结果:RMEC和RMGC均可在膜上正常生长,RMGC间紧密连接。TEM观察高TER值样品中相邻RMEC形成典型的TJ结构。RMEC层TER在8d时达到最高,为(86.3±7.9)Ω·cm2,此后保持相对稳定。在RMGC存在的共培养组TER7d时为(97.6±3.6)Ω·cm2,约为7d时RMEC组的2倍,8d达到峰值(113.5±5.3)Ω·cm2。在iBRB模型发展过程中,ZO-1的表达强度随时间延长而增加。结论:通过RMEC和RMGC的共培养可以建立体外iBRB模型,RMGC加快RMEC间的TJ成熟。     

光损伤鼠视网膜片培养上清液诱导 MSCs 分化为视网膜样细胞的研究

目的：应用大鼠视网膜片光损伤后的培养上清液,在体外诱导大鼠骨髓间充质干细胞（ mesenchymal stem cells , MSCs）成为视网膜样细胞的可能性。 方法：贴壁筛选法分离、培养大鼠MSCs ,流式细胞仪对其细胞纯度鉴定。取材大鼠视网膜神经上皮层作为视网膜片,常规石蜡切片HE染色鉴定各层组织完整性。电镜观察大鼠视网膜片光损伤程度。制备3种诱导分化大鼠MSCs的条件培养液。3种条件培养液均培养诱导至第3代大鼠MSCs 7～8d,用RT-PCR检测视紫红质（Rhodopsin）、神经元特异性烯醇化酶（neuron-specific enolase,NSE）、胶质纤维酸性蛋白（ glial fibrillary acidic protein ,GFAP）等视网膜细胞标志物在诱导后细胞中的表达情况。 结果：HE染色显示大鼠视网膜片取材结构完整,电镜显示大鼠视网膜片光损伤后结构损伤严重。 RT-PCR鉴定：条件培养液诱导大鼠MSCs 7～8d,条件培养液Ⅰ组Rhodopsin （0．3915±0．00644）、NSE （0．2019±0．00682）、GFAP （0.1972±0．00211）,条件培养液Ⅱ组Rhodopsin（0．0983±0．00319）、NSE （0．1048±0．00323）、GFAP （0．1040±0.00254）,条件培养液Ⅲ组Rhodopsin（0．0044±0．00126）、NSE（0．0498±0．00149）、GFAP（0．0467±0．00333）,组间差异有统计学意义。 结论：光损伤大鼠视网膜片培养上清液可诱导大鼠MSCs分化为视网膜样细胞,为干细胞治疗视网膜变性疾病提供新思路。     

增生性玻璃体视网膜病变的药物治疗

增生性玻璃体视网膜病变（PVR）常由于裂孔源性视网膜脱离、眼穿孔伤或眼内手术造成血-视网膜屏障受损,视网膜色素上皮（RPE）细胞进入玻璃体,继而引起RPE细胞、神经胶质细胞、成纤维细胞等在玻璃体内增生,形成以细胞为主的纤维膜。临床上治疗和预防PVR以手术为主,但效果不佳。近来有许多药物治疗PVR的研究报道,就PVR药物治疗研究进展进行综述。     

Apical and basal regulation of the permeability of the retinal pigment epithelium

PURPOSE: The functional characteristics of tight junctions in the outer blood-retinal barrier change during embryonic development and in the presence of disease. A culture model of developing retinal pigment epithelium (RPE) was used to examine the regulation of the tight junctions. METHODS: RPE from chick embryos was cultured on filters that separated the apical and basal medium compartments. Cultures were maintained in various combinations of serum-free medium, serum-free medium that was conditioned by neural retinas, or serum-free medium that was supplemented with bovine pituitary extract, serum, or various hormones. Function was monitored by the transepithelial electrical resistance (TER) or the permeation of small organic tracers. Structure was monitored by immunofluorescence and freeze-fracture electron microscopy. RESULTS: Functional analysis indicated differences in permeability among RPE of different embryonic age and culture conditions. In serum-free medium, the tight junctions were leaky or failed to form. Barrier properties increased if pituitary extract was added to the basal medium chamber or retina-conditioned medium was added to the apical chamber. Retina-conditioned medium was more effective at organizing tight junctional strands into a continuous network, but bovine pituitary extract appeared to modulate the permeability of that network. In combination, they synergistically elevated the TER to physiological levels. Although the thyroid hormone T3 had no effect, serum in the apical medium chamber inhibited the ability of RPE cells to respond to retina-conditioned medium. CONCLUSIONS: Diffusible factors secreted by the neural retina acted synergistically with basolateral stimulation to regulate the structure and function of RPE tight junctions. Serum on the apical side of the RPE monolayer inhibited the ability of retinal factors to upregulate the tight junction barrier.     

Sulforaphane induces thioredoxin through the antioxidant-responsive element and attenuates retinal light damage in mice

PURPOSE: Thioredoxin (Trx) is a multifunctional endogenous redox regulator that protects cells against various types of cellular or tissue stresses. This study was conducted to test whether sulforaphane (SF), a naturally occurring isothiocyanate that is highly concentrated in broccoli sprouts, induces Trx in retinal tissues and whether pretreatment with SF protects against light-induced retinal damage in mice. METHODS: Expression of Trx in mouse retina was analyzed by Western blot and immunohistochemistry. Retinal damage was induced by exposure to white light at 6000 lux for 2 hours. To estimate retinal cell damage, the number of cell nuclei and the percentage of TUNEL-positive cells were counted in the outer nuclear layer and the retinal pigment epithelial (RPE) layer and the electroretinograms recorded. To analyze further the mechanism of Trx induction by SF, cultured human K-1034 RPE cells were used. RESULTS: Both intraperitoneal and oral SF induced Trx protein in the neural retina and RPE. The maximum induction of Trx was observed with intraperitoneal SF 0.5 mg/d for 3 days. After exposure to light, mice pretreated with SF had a significantly lower percentage of TUNEL-positive RPE and photoreceptor cells, a significantly higher number of RPE and photoreceptor nuclei, and greater amplitude of ERG a- and b-waves than in the saline-treated mice. In K-1034 cells, 1 microM SF induced Trx protein, whereas 10 microM SF did not damage cells or augment cellular peroxide production, tested by a lactate dehydrogenase (LDH) release assay and 2',7'-dichlorofluorescein diacetate (DCFH-DA)/flow cytometry, respectively. In the luciferase reporter assay, the antioxidant-responsive element (ARE) played a role in SF-induced Trx expression. In the electrophoretic mobility shift assay, SF induced binding of Nrf2, small Maf, and c-Jun to the ARE of the Trx gene. CONCLUSIONS: SF induced Trx in murine retina and effectively reduced retinal light damage. Evidence suggests that the ARE is involved in the mechanism of Trx induction by SF in RPE cells.     

Prevention of rod disk shedding by detachment from the retinal pigment epithelium

The authors tested whether or not rod outer segment (ROS) disks are shed when the neural retina is detached from the retinal pigment epithelium (RPE). Adult Xenopus were injected with 3H-L-leucine. Later, when the distal disks of their ROSs were labeled with a band of 3H-leucine, their eyes were enucleated. Intact eyecups, eyecups with partially detached retinae, and retinae that were peeled completely away from the RPE were incubated in culture medium. Disk shedding was stimulated by changes in lighting, or the addition of 0.5 mM ouabain. Where the retina was attached, phagosomes in the RPE, and not the ROSs, contained most of the radiolabel. Where there was retinal detachment, ROSs were still heavily radiolabeled near their distal ends. It was concluded that mechanical retinal detachment prevents ROS disk shedding.     

The distribution of Na+,K(+)-ATPase in the retinal pigmented epithelium from chicken embryo is polarized in vivo but not in primary cell culture

The polarity of retinal pigmented epithelia (RPE) from chicken embryos was studied in primary cell culture. Since cultured RPE approximates the morphological polarity of RPE in vivo, we investigated whether this polarity extends to the distribution of plasma membrane proteins that are peculiar to RPE. In contrast to other epithelia, the Na+,K(+)-ATPase of RPE is located in the apical rather than basolateral plasma membrane. To examine this property, we cultured RPE on extracellular matrix-coated filters. Primary cultures were compared to embryonic RPE in situ using electron microscopy and indirect immunofluorescence of frozen sections. The viability and morphology of RPE was improved by using a serum-free medium containing a bovine pituitary extract in conjunction with an extracellular matrix coating derived from Engelbreth-Holm-Swarm tumors. Cultured RPE mimicked the morphology of RPE in vivo with microvilli and junctional complexes on the apical pole and infoldings along the basolateral plasma membrane. Functional tight junctions formed as demonstrated by an EDTA-sensitive, transepithelial electrical resistance, and by the retention of [3H]inulin added to the apical chamber. In 2 hr, only 4-6% of the [3H]inulin crossed the monolayer, compared to 24% in control filters. Despite these features of polarity, the Na+,K(+)-ATPase was detected in both apical and basolateral membranes by immunofluorescence. In embryonic eyes in which the neural retina was removed, the Na+,K(+)-ATPase was confined to the apical membrane. In addition, the polarity of cultured RPE was probed with vesicular stomatitis virus. In contrast to other epithelia, budding virus particles were observed emerging from the apical, as well as basolateral, domain further suggesting the cultured cells were only partially polarized. These data indicate that structural criteria are inadequate to determine if cultured RPE have become polarized in the same manner as the epithelium in vivo.     

Retinal pigment epithelium of new-born rats is capable of phagocytosis of rod outer segments in vitro

The ability of retinal pigment epithelium (RPE) cells of rats at 0, 1, 3, 4, 5, 8, 10, 12 and 15 days after birth towards phagocytosis of rod outer segments (ROS) has been studied in short-term explant culture of the scleral part of the eye. The neural retina was removed before cultivation. The suspension of ROS isolated from the retina of adult rats was layered on top of RPE cells. The phagocytic activity was evaluated by visualization of phagosomes in the cytoplasm of RPE cells after 4-5 hr incubation, using electron microscopy. It has been shown that RPE cells at all the stages studied, including new-born rats, are capable of ROS phagocytosis.     

Integration of tight junctions and claudins with the barrier functions of the retinal pigment epithelium

The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier by regulating the movement of solutes between the fenestrated capillaries of the choroid and the photoreceptor layer of the retina. Blood-tissue barriers use various mechanisms to accomplish their tasks including membrane pumps, transporters, and channels, transcytosis, metabolic alteration of solutes in transit, and passive but selective diffusion. The last category includes tight junctions, which regulate transepithelial diffusion through the spaces between neighboring cells of the monolayer. Tight junctions are extraordinarily complex structures that are dynamically regulated. Claudins are a family of tight junctional proteins that lend tissue specificity and selectivity to tight junctions. This review discusses how the claudins and tight junctions of the RPE differ from other epithelia and how its functions are modulated by the neural retina. Studies of RPE-retinal interactions during development lend insight into this modulation. Notably, the characteristics of RPE junctions, such as claudin composition, vary among species, which suggests the physiology of the outer retina may also vary. Comparative studies of barrier functions among species should deepen our understanding of how homeostasis is maintained in the outer retina. Stem cells provide a way to extend these studies of RPE-retinal interactions to human RPE.     

Glial fibrillary acidic protein increases in Müller cells after retinal detachment

Retinal detachment, separation of the neural retina from the retinal pigment epithelium (RPE), initiates a series of changes in the eye which result in loss of vision if the retina is not rapidly reattached to the RPE. Many of the complex effects of this separation on the cell biology of the retina have yet to be determined. We report here a change in the amount and location of a specific cytoskeletal protein, glial fibrillary acidic protein (GFAP), within Müller cells after retinal detachment. Cat neural retina and RPE were separated by injecting fluid into the extracellular space between the retina and RPE. Normal retinas and retinas detached for 30 days were fixed and embedded for conventional electron microscopy or immunocytochemistry, or homogenized and processed by SDS-PAGE for immunoblot analysis with anti-GFAP. In normal retinas and in attached retinal regions of eyes with retinal detachment, GFAP was detected only in the end feet of the Müller cells as 10 nm diameter filaments and as a diffuse component over the cytoplasm. By contrast, in regions where the retina was detached from the RPE, GFAP was localized throughout the Müller cells in both of these forms. Immunoblots revealed a significant increase in anti-GFAP labeling of a 51,000 MW band from the detached retina.     

Cadmium accumulation in the human retina: effects of age, gender, and cellular toxicity

Tobacco smoking and aging are among the few factors linked to age-related macular degeneration (AMD), a major cause of blindness in the elderly. Recent studies indicate that cadmium (Cd), an environmental toxic trace metal, is approximately four-fold higher in the retinas of smokers compared to non-smokers. In this study, we determined the effects of age and gender on Cd accumulation in human retinal tissues, specifically the neural retina, retinal pigment epithelium (RPE), and choroid. Cadmium levels in cultured RPE cells or retinal tissues isolated from frozen donor eyes were measured using inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrophotometry (GF-AAS). Cadmium uptake in cultured human RPE cells (ARPE-19) was also assessed using GF-AAS. Toxic effects of cadmium were determined from cell loss (measured as a decrease in cell density) and lactate dehydrogenase release (an indicator of membrane disruption). In "young" eyes (< 55 years) Cd was highest in the retinal pigment epithelium and lowest in the neural retina. Cd was higher in all tissues in aged eyes (>or=55 years) and was significantly higher in the neural retina and RPE in older females. Cultured RPE cells exposed to Cd showed altered cell morphology, decreased cell survival, elevated ROS levels and concentration-dependent disruption of membrane integrity. We conclude that cadmium is accumulated differently in the neural retinal and RPE of older men and women. The deleterious effects of Cd on RPE cells indicate that this environmental toxin is a potentially important factor in age-related retinal disease.     

Chick retinal pigment epithelium exhibits glutathione requiring prostaglandin D2 synthetase activity

Prostaglandin synthetic activity of neural retina and retinal pigment epithelium in chick retina was studied using arachidonic acid and prostaglandin H2 (intermediate prostaglandin endoperoxide) as substrates. To obtain sufficient enzyme activity in retinal pigment epithelium, cultured chick retinal pigment epithelial cells were used. Little arachidonic acid was converted into prostaglandins, and details of prostaglandin synthetic activity were not clear. The assay from prostaglandin H2 showed that: 1) preparations consisting of both neural retina and retinal pigment epithelium dissected from 7-day-old chicks have activity of glutathione-requiring prostaglandin D2 synthetase; 2) preparations consisting of only neural retina dissected from 7-day-old chicks have no activity of prostaglandin synthetase; and 3) cultured chick retinal pigment epithelial cells have high activity of glutathione-requiring prostaglandin D2 synthetase.     

Successful cotransplantation of intact sheets of fetal retina with retinal pigment epithelium.

PURPOSE: Many retinal diseases, such as macular degeneration, affect both retinal pigment epithelium (RPE) and photoreceptors. Therefore, retinal repair may require transplantation of both tissues together as a cograft. METHODS: As recipients of retina-RPE cografts, 7- to 10-week-old albino Royal College of Surgeons rats that lose their photoreceptors because of a pigment epithelium defect were used. Freshly harvested intact sheets of RPE with neural retina from pigmented normal rat fetuses were gel embedded for protection and transplanted into the subretinal space. RESULTS: After 6 to 7 weeks, with the support of the cografted RPE sheet, transplanted photoreceptors developed fully in organized parallel layers in the subretinal space. Immunohistochemistry for rhodopsin, rod alpha-transducin, and S-antigen and peanut agglutinin labeling for cone interphotoreceptor matrix domains suggested that the photoreceptors in the graft were capable of normal function. CONCLUSIONS: Freshly harvested intact sheets of fetal RPE and retina, transplanted together into the subretinal space, can develop a normal morphology. Such transplants have the potential to benefit retinal diseases with dysfunctional RPE and photoreceptors.