Y27632体外诱导视网膜色素上皮细胞转分化为神经元样细胞的初步研究

Objective To investigate the feasibility of Y27632 to induce transdifferentiation from human retinal pigment epithelial(hRPE)cells into neuron-like cells in vitro.Methods The third to sixth generation of primary hRPE cells were cultured with 2% fetal bovine serum+Dulbecco's modified eagle medium/F12 culture solution,with(experimental group)or without(control group)10 μmol/L Y27632.At 3,6 hours and 1,3,5,7 days after induction,the morphologic changes of RPE cells were observed by inverted microscope.The expression rate of CK18,Map2,NF200 and Pax6 at 3 days after induction in the experimental and control group were detected by immunofluorescent staining.χ2 test was employed for comparison between the two groups.Results 50.1% cells of the experimental group formed axon-like processes and interconnected each other with typical neuron-like appearance.The expression rates of CK18,Map2,NF200 and Pax6 in the experimental group were 43.88% ,31.90% ,57.45% and 65.79% .while the above indexes in the control group were 93.97% ,4.49% ,22.37% and 8.33% respectively.Compared the expression rate of CK18(χ2=64.763),Map2(χ2=23.634),NF200(χ2=21.261)and Pax6(χ2=25.946)between the two groups,the differences were significant(P＜0.01).Conclusion The hRPE cells can be trans-differentiated into neuron-like cells in vitro bv Y27632.     

Y27632体外诱导视网膜色素上皮细胞转分化为神经元样细胞的初步研究

Objective To investigate the feasibility of Y27632 to induce transdifferentiation from human retinal pigment epithelial(hRPE)cells into neuron-like cells in vitro.Methods The third to sixth generation of primary hRPE cells were cultured with 2% fetal bovine serum+Dulbecco's modified eagle medium/F12 culture solution,with(experimental group)or without(control group)10 μmol/L Y27632.At 3,6 hours and 1,3,5,7 days after induction,the morphologic changes of RPE cells were observed by inverted microscope.The expression rate of CK18,Map2,NF200 and Pax6 at 3 days after induction in the experimental and control group were detected by immunofluorescent staining.χ2 test was employed for comparison between the two groups.Results 50.1% cells of the experimental group formed axon-like processes and interconnected each other with typical neuron-like appearance.The expression rates of CK18,Map2,NF200 and Pax6 in the experimental group were 43.88% ,31.90% ,57.45% and 65.79% .while the above indexes in the control group were 93.97% ,4.49% ,22.37% and 8.33% respectively.Compared the expression rate of CK18(χ2=64.763),Map2(χ2=23.634),NF200(χ2=21.261)and Pax6(χ2=25.946)between the two groups,the differences were significant(P＜0.01).Conclusion The hRPE cells can be trans-differentiated into neuron-like cells in vitro bv Y27632.     

缺氧及小干扰RNA转染对人RPE细胞增生及血小板源性生长因子-BB表达的影响

背景 增生性玻璃体视网膜病变（PVR）为视网膜表面发生无血管、纤维细胞性增生膜,其发生和发展的具体机制尚未完全阐明.人视网膜色素上皮（hRPE）及血小板源性生长因子（PDGF）在PVR发展中的作用是近几年研究的热点. 目的 探讨缺氧对体外培养hRPE细胞PDGF-BB表达及增生的影响. 方法 hRPE细胞在6孔板中培养,实验组用10、15、20、30、40 μmol/L CoCl2模拟体外培养hRPE细胞的缺氧环境,对照组用未加CoCl2的培养液培养hRPE细胞,采用逆转录PCR（RT-PCR）与ELISA法检测PDGF-BB mRNA和蛋白的表达,采用MTT法检测hRPE细胞增生率.依据转染siRNA的不同将细胞分为PDGF-BB siRNA1组、PDGF-BB siRNA2组、PDGF-BB siRNA3组（为针对PDGF-BB的3条不同的siRNA,其中有一条为有效siRNA）、β-actin siRNA组、无关siRNA组和只加Lip2000的空白对照组.转染4～6h后,除空白对照组外,其余各组加入对细胞PDGF-BB mRNA和蛋白及对hRPE细胞增生影响最明显的15 μmol/L CoCl2模拟细胞缺氧环境24 h,检测PDGF-BB mRNA和蛋白及hRPE细胞增生率. 结果 未加CoCl2的对照组未检测出PDGF-BBmRNA和蛋白的表达,不同浓度CoCl2培养hRPE细胞PDGF-BB mRNA和蛋白的表达量不同,差异均有统计学意义（F=43.737,P＜0.01;F=54.612,P＜0.05）,15μmol/L CoCl2组PDGF-BB的表达量最多,与其他各组比较差异均有统计学意义（P＜0.05）.MTT检测结果显示,不同浓度CoCl2处理后PDGF-BB蛋白表达及hRPE细胞增生率明显不同,差异均有统计学意义（F=95.379,P＜0.01;F=63.375,P＜0.05）,15 μmol/L CoCl2组hRPE细胞增生率明显高于其他浓度组,差异均有统计学意义（P＜0.05）,PDGF-BB蛋白表达量与hRPE细胞增生率呈线性正相关（r=0.994,P＜0.05）.各细胞转染组hRPE细胞中PDGF-BB mRNA及蛋白的表达整体比较,差异均有统计学意义（F=156.330、125.650,P＜0.01）,且PDGF-BB siRNA2组PDGF-BB mRNA较其他各组明显下降,差异均有统计学意义（P＜0.01）.MTT检测结果显示,各细胞转染组PDGF-BB蛋白的表达及hRPE细胞增生率明显不同,差异均有统计学意义（F=73.131、98.564,P＜0.01）,PDGF-BB siRNA2组PDGF-BB蛋白的表达及细胞增生率与其他各组比较明显下降,差异均有统计学意义（P＜0.05）,PDGF-BB蛋白表达与hRPE细胞增生率呈线性正相关（r=0.996,P＜0.05）.结论 缺氧能够促进PDGF-BB的表达,PDGF-BB的表达上调可显著促进hRPE细胞的增生.在转染靶向PDGF-BB siRNA后,PDGF-BB的表达受到抑制,可有效降低hRPE细胞的增生率.     

视紫红质蛋白激酶抑制剂对兔增生性玻璃体视网膜病变的作用

目的 分析视紫红质蛋白激酶（ROCK）抑制剂Y27632对兔增生性玻璃体视网膜病变（PVR）的作用。方法 培养兔视网膜色素上皮（RPE）细胞。相差显微镜及免疫荧光染色检测Y27632对RPE细胞-平滑肌肌动蛋白（SMA）压力纤维形成的影响。体外Ⅰ型胶原凝胶收缩试验和噻唑蓝（MTT）试验来检测Y27632对细胞收缩力量和增殖的影响。用第6代兔RPE细胞建立兔PVR模型,玻璃体腔内给予50μmol／L Y27632,每周1次,持续28d,以牵拉性视网膜脱离的发生率来评估药物的体内效应。行视觉电生理和组织学检查以分析该药的毒性。结果 50μmol／L Y27632破坏了兔RPE细胞α-SMA压力纤维的形成,并减弱了RPE细胞产生的收缩力（P〈0．01）;RPE细胞的增殖不受Y27632的影响。Y27632用药组的牵拉性视网膜脱离的发生率降低（P〈0．01）。在用药组中,未发现明显的视网膜组织结构和功能的损害。结论 特异性ROCK抑制剂Y27632可减弱RPE细胞产生的收缩力,并且可阻止兔PVR的发展。该药无明显的副作用,有可能成为一种防治PVR的有效方法。     

维生素E对大剂量蓝光诱导损伤视网膜色素上皮细胞的影响

目的:研究维生素E(Vit E)对大剂量蓝光诱导人视网膜色素上皮(hRPE)细胞损伤的影响,为减少蓝光损伤hRPE细胞的预后方案提供思路。方法:用3000±150Lx蓝光建立hRPE细胞损伤模型;利用流式细胞术检测照射时间分别为0、3、6、9、12、24h的6组hRPE细胞凋亡率及活性氧相对量;利用流式细胞术检测照射0h组、照射6h组、照射6h前或后加不同浓度Vit E组(Vit E的浓度分别为10、50、100μmol/L)的hRPE细胞凋亡情况和活性氧相对量,并采用Hoechst 33258试剂染色在荧光显微镜下观察hRPE细胞的荧光强度。结果:与照射0h组相比,照射3、6、9、12、24h组的hRPE细胞活性氧相对量明显增加(均P<0.01),照射6、9、12、24h组的hRPE细胞凋亡率也明显增加(均P<0.01),但照射3h组的hRPE细胞凋亡率无明显增加,差异无统计学意义(P=0.46)。与照射6h组相比,除照射6h前加入10μmol/L的hRPE细胞凋亡率(P=0.66)外,其他加Vit E的实验组hRPE细胞活性氧相对量和凋亡率明显减少、细胞中Hoechst 33258释放蓝色荧光逐渐减弱,且呈浓度依赖(均P<0.01)。与照射0h组相比,加Vit E的6组hRPE细胞活性氧相对量和凋亡率有差异(均P<0.01)。同一浓度的Vit E,除10μmol/L Vit E的hRPE细胞凋亡率在照射前或后加无差异(P=0.08)外,照射后加Vit E组比照射前加Vit E组的hRPE细胞活性氧相对量、凋亡率明显减少(均P<0.01)。结论:hRPE细胞经蓝光照射后出现胞内活性氧相对量增多的现象早于细胞凋亡,清除胞内活性氧是减少大剂量蓝光诱导hRPE细胞损伤的思路。Vit E可保护由大剂量蓝光诱导的RPE细胞损伤,这种效应随Vit E浓度增加而增强,且照射后加入比照射前加入的效果更好。但需要一定剂量的Vit E才能显效,而且无法完全修复损伤。     

SD大鼠视网膜神经细胞培养上清液对胚胎干细胞体外分化的诱导作用

目的 探讨视网膜神经细胞培养的上清液对胚胎干细胞（embryonic stem cells, ES）体外分化的诱导作用。 方法 收集SD大鼠视网膜神经细胞培养上清液，抽滤后按2∶3比例与DMEM培养液混合，用该混合液进行ES 细胞的诱导分化，每天倒置相差显微镜观察ES细胞的生长及分化情况,对诱导分化后的细胞进行神经丝蛋白(nellcofilament protein，NFP)免疫组织化学检查。 结果 加入了视网膜神经细胞培养上清液的ES细胞生长出类似神经细胞突起样结构，NFP免疫组织化学染色阳性。 结论 SD大鼠视网膜神经细胞培养的上清液具有诱导ES细胞向神经细胞分化的作用。 (中华眼底病杂志, 2002, 18: 134-136)     

整合素连接激酶对人视网膜色素上皮细胞增殖的影响

目的研究整合素连接激酶(integrin linked kinase,ILK)小分子干扰RNA(siRNA)对人视网膜色素上皮(human retinal pigment epithelium,hRPE)细胞增殖的影响。方法培养hRPE细胞,角蛋白鉴定。以ILK为靶基因设计合成特异性的siRNA干扰片段转染hRPE细胞。荧光显微镜下观察转染效率,选择转染效率最高的干扰片段进行细胞转染。RT-PCR检测siRNA对ILK基因表达的抑制作用,MTT法检测转染前后hRPE细胞增殖活性。结果 ILK-siRNA可以成功转染至hRPE细胞,转染24h后hRPE细胞中ILK mRNA的相对表达水平在正常对照组、单纯脂质体组、阴性对照组及转染组中分别为0.44±0.48、0.43±0.38、0.42±0.47、0.32±0.71,正常对照组、单纯脂质体组和阴性对照组中ILKmRNA表达差异无统计学意义(P>0.05),转染组ILKmRNA的表达较正常对照组明显降低,差异有显著统计学意义(F=21.78,P<0.01)。不同浓度ILK-siRNA转染组在不同时间点细胞增殖较正常培养组明显降低(P<0.01),50nmol·L-1浓度转染组对hRPE细胞的生长抑制最明显。结论 hRPE细胞表达ILK,siRNA抑制ILKmRNA的表达,在一定范围呈时间浓度依赖性抑制hRPE细胞增殖。     

Y27632对急性视网膜缺血再灌注大鼠视网膜组织形态学的影响

研究Rho激酶抑制剂Y27632 对视网膜缺血再灌注损伤大鼠视网膜组织形态学的影响。方法：实验研究。将60只SD大鼠随机分为4组，每组15只：正常对照组（正常组）、急性缺血再灌注损伤组（IRI组）、0.9%氯化钠溶液对照组（生理盐水组）、Y27632治疗组（Y27632组）。再灌注损伤后24 h（10只）和168 h（5只）处死各组动物，行HE染色、ADP酶染色检查，光镜下观察大鼠视网膜组织病理学变化及视网膜厚度变化。数据采用单因素方差分析。结果：正常组大鼠视网膜结构清晰，三层细胞结构排列整齐。IRI组于再灌注24 h后视网膜厚度增加，内外丛状层组织疏松，视网膜节细胞、内外核层细胞水肿明显、排列紊乱，视网膜节细胞减少。168 h后，视网膜水肿消退、厚度变薄、呈萎缩状，神经节细胞及内外核层细胞数量减少，在视网膜前和神经纤维层可见毛细血管。再灌注 24 h后，IRI组视网膜厚度较正常组增加（P=0.005），Y27632组视网膜厚度低于生理盐水组（P=0.032）。再灌注168 h后，IRI组视网膜厚度低于正常组（P<0.001），Y27632组视网膜厚度较生理盐水组增加（P=0.025）。正常组大鼠视网膜血管自视乳头发出，向四周呈放射状均匀分布，毛细血管网结构清晰。再灌注24 h后，IRI组视网膜血管管径变细，走行较僵直，分支减少，视乳头周围及中周部视网膜可见大片无灌注区，无灌注区周围可见新生血管芽渐成网状。Y27632组可见视乳头周围及中周部视网膜局部无灌注区形成，无灌注区周围可见新生血管。后极部4PD无灌注区面积明显小于IRI组及生理盐水组。结论：Y27632玻璃体腔注射可以减轻视网膜缺血再灌注早期的视网膜水肿，减少视网膜神经节细胞的凋亡，减少视网膜新生血管生成，减轻再灌注晚期的视网膜萎缩，具有视神经保护作用。     

脂褐质荧光基团N-亚视黄基-N-视黄基乙醇胺在人视网膜色素上皮细胞蓝光损伤中的作用研究

目的探讨成人视网膜色素上皮（hRPE）细胞对脂褐质荧光基团N-亚视黄基-N-视黄基乙醇胺（A2E）的摄取及A2E在hRPE细胞蓝光损伤中的作用。方法全反式视黄醛和乙醇胺混合,体外合成A2E。体外培养hRPE细胞。将A2E加入hRPE细胞培养液中,使A2E的浓度分别为25、50、100μmoL／L。观察hRPE细胞对A2E的摄取。用蓝光（450nm）照射hRPE细胞20min,光照强度70mW／mm^2,CCK-8检测细胞活力,Hoechst 33342荧光素染色、流式细胞仪检测细胞凋亡情况。结果全反式视黄醛（100．0mg）和乙醇胺（9．5mg）混合后生成53．8mg的A2E。吞噬A2E的hRPE细胞中能够检测到自发荧光,主要分布在细胞核周围。蓝光照射后,含有A2E的hRPE细胞活力下降,下降程度随A2E浓度增加而增强。不含A2E的hRPE细胞,经蓝光照射后,细胞活力未见明显下降。蓝光照射含有A2E的hRPE细胞,细胞核中出现浓染的碎块状荧光,流式细胞仪检测可见凋亡细胞特有的亚二倍体峰,加入25μmoL／L的A2E,光照后12、24、36及48h,细胞凋亡率分别为（12．11±2．32）％、（31．21±3．72）％、（64．23±3．53）％及（58．71±3．48）％。仅接受光照不加入A2E、不接受光照（加入或不加入A2E）的hRPE细胞凋亡率在光照后各时间点的平均值均小于5％。结论在hRPE细胞蓝光损伤的过程中,单独的光照射不会造成明显的细胞损伤或凋亡,A2E的存在是蓝光损伤的因素之一。提示在老年人中,含有较多脂褐质的hRPE细胞容易受到蓝光损伤。（中华眼科杂志．2007,43：1017-1021）     

Protection of retinal pigment epithelial cells from oxidative damage by oltipraz,a cancer chemopreventive agent

OBJECTIVE: To determine whether oltipraz (4-methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione) protects against oxidative injury in cultured human retinal pigment epithelial (hRPE) cells. METHODS: Primary cultured hRPE cells were incubated with various concentrations of oltipraz followed by treatment with the chemical oxidant tert-butylhydroperoxide (tBH). Cell viability was assessed by release of lactate dehydrogenase (LDH) and cleavage of WST-1. Intracellular and mitochondrial levels of glutathione (GSH) were measured by HPLC. Glutathione S-transferase (GST), NADPH-quinone reductase (NQR), and glutathione peroxidase (GPx) were measured by specific enzyme activity assays. RESULTS: Treatment of hRPE cells with oltipraz inhibited tBH-induced cell death in a concentration-dependent manner with significant inhibition at 50 micro M. Olitpraz (50 micro M) increased GSH levels in hRPE cells by approximately 18% and in hRPE mitochondrial fractions by approximately 50% after 24 hours of exposure. Treatment with oltipraz increased GST and NQR activities by approximately 21% and 11%, respectively. CONCLUSIONS: Oltipraz protects hRPE cells against tBH induced injury. The mechanism of protection is likely to include increased cellular and mitochondrial GSH levels and induction of detoxification enzymes, including GST and NQR. Dietary supplementation with oltipraz or other dithiolethiones may help protect the hRPE against oxidant induced injury.     

Involvement of rho-kinase pathway in contractile activity of rabbit RPE cells in vivo and in vitro

PURPOSE: Increased alpha-smooth muscle actin (alpha-SMA) expression in epiretinal membranes causes tractional retinal detachment (TRD) in proliferative vitreoretinopathy (PVR). The Rho-A/Rho-associated kinase signaling pathway is a principal mediator of contractile force generation in nonmuscle cells. In the current study, the relation between the Rho-kinase pathway and alpha-SMA expression and type I collagen gel contractile activity in retinal pigment epithelial (RPE) cells was investigated, using Y27632, a specific inhibitor of p160ROCK, and the involvement of the Rho-kinase pathway was evaluated in a rabbit PVR model with cultured RPE cells and platelet-rich plasma (PRP). METHODS: RPE cells were obtained from rabbits and cultured. The number of passages and the effect of Y27632 on alpha-SMA expression were studied by immunohistochemistry and immunoblot analysis. An in vitro type I collagen gel contraction assay and MTT assay evaluated the effect of Y27632 on RPE cell contractile force and proliferation. Cultured sixth-passage rabbit RPE cells were coinjected with PRP intravitreally, followed by 50 micro M of Y27632, injected weekly. The presence of TRD was assessed until 28 days to evaluate the effect of Y27632 in vivo. RESULTS: Expression of alpha-SMA was increased according to the passages. Y27632 suppressed alpha-SMA expression in cultured RPE cells and impaired contractile force. Y27632 did not affect the proliferative potential. Y27632 significantly (P < 0.01) reduced TRD development. CONCLUSIONS: Y27632 decreased alpha-SMA expression and the contractile force generated by RPE cells and attenuated PVR, indicating the involvement of the Rho-kinase pathway in cell-dependent collagen contraction in vitro and in vivo. The drug may affect the biological event by inhibiting alpha-SMA expression, and Y27632 could be useful for preventing PVR.