骨髓间充质干细胞在视网膜色素变性大鼠视网膜下的分化

目的 研究骨髓间充质干细胞(MSCs)在视网膜色素变性(RP)大鼠体内的分化. 方法 Lewis大鼠腹腔注射3%NaIO3 100mg/kg,建立大鼠RP模型,将体外培养的MSCs植入视网膜下腔,用免疫荧光标记法对MSCs进行追踪,并观察术后第1、2、3、4、5周MSCs在该微环境中的分化.结果 术后第1周即可见MSCs位于视网膜色素上皮(RPE)层与光感受器细胞层,但全角蛋白(PCK)及Rhodopsin标记阴性,第3周开始可见MSCs在体内表达PCK及Rhodopsin.结论 MSCs植入RP模型大鼠视网膜下腔后可存活,主要分布于RPE层和视锥、视杆细胞层,并表达RPE细胞和光感受器细胞的表面标志.     

视网膜下间隙移植经基因修饰的视网膜色素上皮细胞对大鼠光感受器变性及视功能的保护作用

目的 以RCS大鼠作模型,研究经基因修饰的永生化视网膜色素上皮细胞(RPE)视网膜下移植对光感受器变性的保护作用。方法 在绿色荧光蛋白基因逆转录病毒感染的基础上,利用脂质体介导节状神经生长因子(CNTF)表达质粒转移,修饰成人RPE细胞系CRL-2302。将1×105个表达绿色荧光蛋白(GFP)或GFP及CNTF的RPE细胞移植到4～5周龄RCS大鼠右眼视网膜下间隙,左眼不移植或注射。PBS作为对照。术后2、4、6、8、10和12周作荧光显微镜、光镜、电镜及电生理检查。结果 荧光显微镜观察,术后1周移植的人RPE细胞在RCS大鼠视网膜下间隙已扩散到几乎整个眼底,但随时间延长移植的细胞逐渐减少,术后6周仅残留少量移植细胞。光镜及电镜观察显示移植眼保留的光感受器数量明显较对照眼多,凋亡细胞则较对照跟少。此外,移植眼宿主RPE细胞形态较正常,并可见吞噬小体。视网膜电图(ERG)检查结果表明部分移植眼视网膜功能明显较对照眼好。结论 经过基因修饰的RPE细胞移植可延缓RCS大鼠视网膜光感受器变性,为治疗视网膜变性提供了新的途径。(中华眼科杂志,2004,40:552-556)     

骨髓间充质干细胞在视网膜色素变性大鼠视网膜下的分化

目的:研究骨髓间充质干细胞（MSC）在视网膜色素变性（RP）大鼠体内的分化。方法:Lewis大鼠腹腔注射30g/L NaIO₃ 100mg/kg,建立大鼠RP模型,将体外培养的MSC植入视网膜下腔,用免疫荧光标记的方法对MSC进行追踪,并观察术后第1,2,3,4,5wk MSC在该微环境中的分化。结果:术后第1wk即可见MSC位于视网膜色素上皮（RPE）层与光感受器细胞层,但全角蛋白（PCK）及rhodopsin标记阴性,第3wk开始可见MSC在体内表达PCK及rhodopsin。结论:MSC植入RP模型大鼠视网膜下腔后可存活,主要分布于RPE层和视锥、视杆细胞层,并表达RPE细胞和光感受器细胞的表面标志。     

Müller细胞对大鼠光感受器变性及视功能的保护作用

目的以RCS视网膜色素变性大鼠为模型,研究经诱导产生神经干细胞特性的Müller细胞视网膜下腔移植对光感受器变性的保护作用。方法向6周龄VC大鼠玻璃体腔内注射神经毒素混合液（包含NMDA、kainate、FGF2和胰岛素）刺激视网膜Müller细胞。1周后取材分离Müller细胞体外原代培养。将细胞标记后,以每眼1×10^5个细胞密度移植到6周龄RCS大鼠右眼视网膜下腔,左眼分组注射正常Müller细胞和PBS作为同型对照及阴性对照。术后分别于第1、3、5、7周,行视网膜铺片、组织病理学及视觉电生理检查。结果培养的Müller细胞纯度可达96％以上,其中表达神经干细胞标志物的细胞占总细胞量的53％以上。组织病理学观察显示,在相同时间点移植眼保留的光感受器细胞数量明显较同型对照眼多,同型对照移植眼保留的光感受器细胞数量明显较阴性对照眼多。视网膜电图（ERG）检查结果与病理学结果相符。结论视网膜下腔移植经诱导产生神经干细胞特性的Müller细胞可以有效延缓RCS大鼠视网膜光感受器变性,为治疗视网膜变性疾病提供了新的途径。     

BMSCs联合ChABC对视网膜变性大鼠光感受器细胞凋亡的影响

目的：研究骨髓间充质干细胞（ bone mesenchymal stem cells, BMSCs ）联合硫酸软骨素酶（ chondroitinaseABC, ChABC）行视网膜下腔注射对碘酸钠诱导的视网膜变性大鼠光感受器细胞凋亡的影响。
　　方法：选取40只SD大鼠行腹腔注射碘酸钠（ NaIO3,30g／L,100mg／kg）造视网膜变性模型,分为A组不干预组,B组BMSCs注射组,C组BMSCs＋ChABC注射组,D组PBS注射组。造模后28d将ChABC处理或未处理的BMSCs注射入大鼠视网膜下腔,对照组注射PBS液,21 d后处死大鼠并取出眼球,行视网膜HE染色、视网膜细胞凋亡及免疫组化检测。
　　结果：B组凋亡率、外核层细胞数与A组、D组比较,差异均有统计学意义（P＜0．05）。 C组凋亡率、外核层细胞数与A组、D组比较,差异均有统计学意义（ P＜0．05）。 B组凋亡率、外核层细胞数与C组相比,差异无统计学意义（P＞0．05）。免疫组化显示BMSCs在眼内表达GFAP抗原。结论：BMSCs联合ChABC行视网膜下腔注射可缓解视网膜变性大鼠光感受器细胞的凋亡,延缓细胞数目的减少,从而保护视网膜光感受器细胞。     

骨髓间充质干细胞在碘酸钠注射大鼠视网膜下的分化

目的 研究骨髓间充质干细胞(BMMSCs)在视网膜色素上皮(RPE)受损的大鼠模型眼中的分化情况.方法 体外培养Wistar大鼠的BMMSCs,用病毒上清液转染EGFP,移植到经静脉注射NaIO3破坏RPE细胞的大鼠的视网膜下腔,用免疫荧光标记的方法 对BMMSCs进行追踪并观察术后5周的分化情况.结果 BMMSCs的EGFP转染比例可达到76.9%,术后第5周可见BMMSCs位于视网膜下区域,未整合入神经视网膜层,并表达角蛋白(CK)、视紫红质(rhodopsin)和胶质纤维酸性蛋白(GFAP).结论 BMMSCs植入RPE受损伤的大鼠视网膜下腔后可存活,并表达RPE细胞、光感受器细胞和星形胶质细胞的特异性标志.     

碘酸钠对小鼠视网膜形态和功能变化的影响

目的：：探讨碘酸钠鼠尾静脉注射导致的C57 BL/6 J小鼠视网膜形态和功能的变化。方法：将60只6~8周龄C57 BL/6 J小鼠分为正常对照组和碘酸钠组。碘酸钠组经鼠尾静脉注射碘酸钠(35mg/kg),分别于注射后6h,1、3、5、8d进行眼底照相、OCT和电生理检测;正常对照组注射同等剂量的生理盐水。所有小鼠摘除眼球制作石蜡切片进行HE染色。结果：正常对照组小鼠视网膜呈淡红色,视盘呈黄色,视网膜血管呈放射状走行。鼠尾静脉注射碘酸钠后6h即可见到眼底黄白色类似玻璃膜疣样改变,但此时OCT和ERG尚无明显变化。注射后1d,眼底改变加重,类玻璃膜疣的改变逐渐增加,OCT可见RPE层色素紊乱,光感受器和外核层受损。注射后3d,视网膜损伤进一步加重,视网膜出现水肿,注射后5d水肿消失,视神经变白,眼底病灶进一步增多。注射后8d,RPE层、感光细胞层及外核层结构破坏明显,几乎没有正常结构。在此过程中, ERG表现为a波、b波振幅下降,并呈时间依赖性加重。 HE染色结果显示,对照组小鼠视网膜各层细胞排列规则整齐,密度均匀。碘酸钠组小鼠外层视网膜呈波浪状改变,RPE层正常结构消失,可见黑色圆形沉积物,随时间延长,黑色沉积物逐渐增多,至注射后第8 d时几乎没有正常RPE结构。结论：碘酸钠经鼠尾静脉注射后,可以很好地模拟年龄相关性黄斑变性的发病过程,视网膜出现明显的形态和功能变化,为年龄相关性黄斑变性的研究提供一个较好的动物模型。     

Müller细胞对大鼠光感受器变性及视功能的保护作用

目的以RCS视网膜色素变性大鼠为模型,研究经诱导产生神经干细胞特性的Müller细胞视网膜下腔移植对光感受器变性的保护作用。方法向6周龄VC大鼠玻璃体腔内注射神经毒素混合液（包含NMDA、kainate、FGF2和胰岛素）刺激视网膜Müller细胞。1周后取材分离Müller细胞体外原代培养。将细胞标记后,以每眼1×10^5个细胞密度移植到6周龄RCS大鼠右眼视网膜下腔,左眼分组注射正常Müller细胞和PBS作为同型对照及阴性对照。术后分别于第1、3、5、7周,行视网膜铺片、组织病理学及视觉电生理检查。结果培养的Müller细胞纯度可达96％以上,其中表达神经干细胞标志物的细胞占总细胞量的53％以上。组织病理学观察显示,在相同时间点移植眼保留的光感受器细胞数量明显较同型对照眼多,同型对照移植眼保留的光感受器细胞数量明显较阴性对照眼多。视网膜电图（ERG）检查结果与病理学结果相符。结论视网膜下腔移植经诱导产生神经干细胞特性的Müller细胞可以有效延缓RCS大鼠视网膜光感受器变性,为治疗视网膜变性疾病提供了新的途径。     

Tetramethylpyrazine在视网膜色素上皮细胞变性及脉络膜血流和RPE细胞氧化应激中的作用

目的:研究1%Tetramethylpyrazine(TMP)在视网膜色素上皮细胞(RPE)变性,脉络膜血流和RPE细胞氧化应激中的作用。方法:在碘酸钠诱导的大鼠RPE变性研究中,1%TMP滴眼液预先处理1wk,3次/d,1wk后予碘酸钠舌下静脉注射,在2wk和4wk末,视网膜电图(ERG)测量c波。色素微球体技术分析高眼压状态下TMP对脉络膜血流的影响。Methylthiazoltetrazolium(MTT)分析TMP在各种氧化应激中对RPE的保护作用。结果:碘酸钠注射后2wk,碘酸钠组ERG的c波下降至对照组的36%(P<0.01)。4wk后,碘酸钠组下降至对照组的46%(P<0.01),而1%TMP+碘酸钠组下降至对照组的77%(P<0.01)。与碘酸钠组比较,1%TMP+碘酸钠组控制了67%的c波下降(P<0.05)。在脉络膜血流的测量中,30,60,和120min的结果显示,TMP显著增加脉络膜血流。在氧化应激部分,不同浓度的TMP在各种氧化应激损伤中,对RPE都有各种程度的保护作用。结论:浓度为1%Tetramethylpyrazine可以显著保护碘酸钠和氧化应激诱导的RPE变性,增加脉络膜血流,并可能在AMD的治疗中发挥作用。     

Cyclosporine玻璃体腔内注射对异种视网膜色素上皮移植的排异抑制作用

目的 观察兔眼视网膜下腔植入人胚眼视网膜色素上皮（retinal pigment epithe-lium,RPE）后不同时期的眼底和组织学改变。研究环胞菌素A（Cyclosporines,CsA）玻璃体腔内注射能否抑制人胚眼RPE在兔眼视网膜下腔中诱导的异种移植排异反应。方法 人胚眼色素上皮片和浓缩色素上皮细胞悬液植入36只兔眼的视网膜下腔,其中16眼为对照组,用于观察排异的自然转规。分别7d(8眼）和30d(8眼）后获取组织标本。另20眼为实验组。RPE移植后,每周一次玻璃体腔内注射CsA 1mg(12眼）或CsA0.1mg(8眼）。视网膜和视神经的毒性反应使用ERG进行检查。结果 人胚眼RPE片和浓缩的RPE细胞均能在视网膜下腔短期存活。移植的RPE与视细胞结合良好并显示吞噬功能。排异反应发生时间约在术后10～30d。对照组中7d的排异发生率为0/8;30d排异发生率为7/8。排异发生后荧光造影中移植区为高荧光区,组织切片中显示有大量的组织细胞积聚。CsA1mg组30d排异发生率为0/12,0.1mg组为5/8。ERG波幅的下降与CsA剂量和注射次数呈正相关。结论 异种RPE视网膜下腔移植在无免疫抑制剂的条件下,只能短期存活。CsA玻璃体腔中注射能抑制异种RPE移植的排异反应但易引起明显的视网膜毒性反应。     

Retinal degeneration and RPE transplantation in Rpe65(-/-) mice

PURPOSE: To determine whether transplanting normal retinal pigment epithelium (RPE) into the subretinal space influences photoreceptor function and degeneration in Rpe65(-/-) mice. METHODS: RPE cells were isolated from eyes of normal mice and transplanted to the subretinal space of one eye of Rpe65(-/-) mice. The other eye received a subretinal injection of saline or was not touched. Corneal electroretinograms (ERGs) from both eyes were monitored before and after surgery to follow progression of the degeneration. The width of the outer nuclear layer was measured in the area of transplantation and compared with a similar area in control retinas. RESULTS: Transplantation of RPE increased ERG amplitude maximally at 3.7 weeks after surgery. This rescue effect slowly diminished with time. Sham surgery had little effect on the ERG. The width of the outer nuclear layer in the area receiving RPE transplants was slightly greater than in control subjects. Evidence of the presence of RPE transplants in the subretinal space decreased with time after transplantation without signs of inflammation. CONCLUSIONS: Retinal degeneration in the Rpe65(-/-) mice is slowly progressive. Photoreceptor function can be transiently increased for several months and anatomic degeneration slightly reduced in Rpe65(-/-) mice by RPE cell transplantation. Loss of the rescue effect may be due to degeneration of the transplanted RPE.     

Transplantation of CX3CL1-expressing Mesenchymal Stem Cells Provides Neuroprotective and Immunomodulatory Effects in a Rat Model of Retinal Degeneration

Purpose: To investigate the neuroprotective and immunomodulatory effects of mesenchymal stem cells (MSCs) engineered to secrete CX3CL1 on the light-injured retinal structure and function.

Methods: Normal MSCs and CX3CL1-expressing MSCs (CX3CL1-MSCs) were transplanted into the subretinal space of light-injured rats. By ERG and TUNEL methods, their rescue effect of the host retina was compared with untreated light-injured and vehicle-injected rats. Activated microglia in the retina were stained by ED-1 antibody, and Western blot was performed to quantify cytokines secreted by the retina post-transplantation.

Results: ERG analysis showed better function in CX3CL1-MSC-injected group than other groups at 21 days after transplantation (p?<?0.05). CX3CL1-MSCs inhibited apoptosis of the retinal cells and microglial activation. Neurotrophic factors expression in host retina that received CX3CL1-MSCs was stronger than in the retina that received normal MSCs. Conversely, the expression of proinflammatory factors was downregulated.

Conclusions: CX3CL1-MSCs subretinal transplantation may enhance protective effect against light-induced retinal degeneration.     

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.     

Systemically transferred hematopoietic stem cells home to the subretinal space and express RPE-65 in a mouse model of retinal pigment epithelium damage

Stem cell regeneration of damaged tissue has recently been reported in many different organs. Since the loss of retinal pigment epithelium (RPE) in the eye is associated with a major cause of visual loss - specifically, age-related macular degeneration - we investigated whether hematopoietic stem cells (HSC) given systemically can home to the damaged subretinal space and express markers of RPE lineage. Green fluorescent protein (GFP) cells of bone marrow origin were used in a sodium iodate (NaIO(3)) model of RPE damage in the mouse. The optimal time for adoptive transfer of bone marrow-derived stem cells relative to the time of injury and the optimal cell type [whole bone marrow, mobilized peripheral blood, HSC, facilitating cells (FC)] were determined by counting the number of GFP(+) cells in whole eye flat mounts. Immunocytochemistry was performed to identify the bone marrow origin of the cells in the RPE using antibodies for CD45, Sca-1, and c-kit, as well as the expression of the RPE-specific marker, RPE-65. The time at which bone marrow-derived cells were adoptively transferred relative to the time of NaIO(3) injection did not significantly influence the number of cells that homed to the subretinal space. At both one and two weeks after intravenous (i.v.) injection, GFP(+) cells of bone marrow origin were observed in the damaged subretinal space, at sites of RPE loss, but not in the normal subretinal space. The combined transplantation of HSC+FC cells appeared to favor the survival of the homed stem cells at two weeks, and RPE-65 was expressed by adoptively transferred HSC by four weeks. We have shown that systemically injected HSC homed to the subretinal space in the presence of RPE damage and that FC promoted survival of these cells. Furthermore, the RPE-specific marker RPE-65 was expressed on adoptively transferred HSC in the denuded areas.     

Subretinal delivery of immunoglobulin G with gold nanoparticles in the rabbit eye

Purpose  To examine the feasibility of subretinal delivery of immunoglobulin G (IgG) adsorbed onto gold nanoparticles (GNPs) and its histologic distribution in the rabbit retina after the injection. Methods  Goat IgG was adsorbed onto GNPs electrostatically. Goat IgG-adsorbed GNPs or buffer with goat IgG was injected into the subretinal space of rabbit eyes and followed up for 3 months by examination of fundus photographs, immunohistochemistry against goat IgG, and transmission electron microscopy (TEM). Human retinal pigment epithelial cells (ARPE-19 cells) were cultured, and cell proliferation with or without GNPs was assayed. Results  At 1 week after the subretinal injection of goat IgG-adsorbed GNPs, retinal degeneration was observed in the outer retina, and goat IgG was immunolabeled in the retinal pigment epithelium (RPE) and the photoreceptor cells. TEM showed GNPs located in the outer segments and in the lysosomes in the RPE at 1 month and no apparent cytotoxicity of the RPE. There were no inhibitory effects of GNPs on proliferation of ARPE-19 cells. Conclusions  Goat IgG was successfully delivered into photoreceptor cells and RPE using GNPs, though retinal degeneration in the outer retina occurred in this model. This might be an alternative drug delivery method to photoreceptors and RPE.     

体外诱导大鼠骨髓间充质干细胞向视网膜色素上皮细胞分化的可行性研究

目的 探讨体外诱导大鼠骨髓间充质干细胞(rMSCs)向视网膜色素上皮(RPE)细胞分化的可行性.方法 采用贴壁筛选法分离、培养Brown-Norway(BN)rMSCs.将反复冻融制成的BN大鼠RPE细胞裂解液加入到rMSCs培养体系中,鉴定被诱导的细胞是否同时表达RPE细胞的特征性标记物细胞角蛋白(CK)与S-100.结果 经RPE细胞裂解液诱导的rMSCs生长速度减慢,细胞呈长梭形,周边有毛刺样突起.免疫印迹法和双重免疫荧光标记显示部分经诱导的细胞同时表达CK与S-100.流式细胞术显示14.1%的细胞能够同时表达CK与S-100.结论 rMSCs经RPE细胞裂解液诱导后能够向RPE细胞方向分化.     

Differentiation of rat mesenchymal stem cells transplanted into the subretinal space of sodium iodate-injected rats

Purpose: The differentiation of rat bone marrow mesenchymal stem cells (MSCs) was investigated in a retinal pigment epithelium (RPE) damage model induced by the administration of sodium iodate. Methods: Cultured rat MSCs were transfected with enhanced green fluorescent protein and transplanted into the subretinal space of rats injected 4 days earlier with sodium iodate. Immunofluorescence analysis was performed 5 weeks later. Results: The transduction efficiency was 99.9%. Viable MSCs were detected 5 weeks after transplantation, mainly in the subretinal space. The cells expressed pan‐cytokeratin, glial fibrillary acidic protein and rhodopsin. Conclusions: Bone marrow MSCs transplanted into the subretinal space of sodium iodate‐injected rats have the ability to differentiate into RPE, photoreceptor and glial lineage cells.     

Adenovirally transduced bone marrow stromal cells differentiate into pigment epithelial cells and induce rescue effects in RCS rats

PURPOSE: To determine the potential of adenovirally transduced bone marrow stromal cells (BMSCs) to differentiate into retinal pigment epithelial-like cells and to evaluabe possible rescue effects after transplantation into the retinas of Royal College of Surgeons (RCS) rats. METHODS: Through a high-capacity adenoviral vector expressing either green fluorescent protein (GFP) or pigment epithelial-derived factor (PEDF), rat MSCs were transduced in vitro before subretinal transplantation into Wistar rats or, alternatively, RCS rats. Two months after cell injection, the rats were killed and the eyes enucleated. The eyes were then investigated light microscopically or processed for electron microscopic investigations. Cell differentiation and integration were analyzed immunocytochemically using antibodies against cytokeratin and the tight junction protein ZO-1. Electroretinography was performed 16 days after injection of cells, to check whether a functional rescue could be detected. RESULTS: In vitro experiments in cocultured human MSCs and human RPE cells showed that MSCs adopted RPE-like characteristics. In grafting experiments, some rat MSCs integrate into the host RPE cell layer of Wistar and RCS rats, indicated by their hexagonal morphology. Subretinally transplanted cells express the epithelial marker cytokeratin and establish tight junctions with the host RPE cells. Furthermore, rescue effects can be demonstrated after grafting of vector-transduced and nontransduced MSCs in semithin sections of dystrophic retinas. Ultrastructurally, MSCs can be detected on top of host RPE and in close contact with photoreceptor outer segments phagocytosing rod outer segments. CONCLUSIONS: Taken together, these results raise the possibility that MSCs have the potency to replace diseased RPE cells and deliver therapeutic proteins into the subretinal space to protect photoreceptor cells from degeneration.