氧诱导视网膜新生血管模型中基质细胞衍生因子1的表达及机制研究

目的: 观察基质细胞衍生因子1(SDF-1)在氧诱导视网膜新生血管(OIR)模型中的表达情况,并初步研究其在OIR模型中的促新生血管生长机制。方法: 30只C57BL/6J新生小鼠随机分为2组。其中15只小鼠置于氧浓度为75%的容器内饲养5 d,再转移至正常空气下饲养5 d,作为高氧诱导组;另15只小鼠一直在正常空气中饲养,作为正常对照组。免疫组织化学方法检测视网膜SDF-1、CD14蛋白的定位及含量,real-time PCR法检测视网膜SDF-1 mRNA的表达。结果: 与正常对照组相比,高氧诱导组突破视网膜内界膜的内皮细胞核数目明显增多(P<0.01),血管分支减少,大血管扩张、迂曲。两组小鼠视网膜神经上皮均可见SDF-1和CD14阳性染色,但高氧诱导组的SDF-1和CD14含量明显高于正常对照组(均P<0.01)。并且视网膜SDF-1与CD14的蛋白含量存在正相关(r=0.898,P<0.01)。视网膜SDF-1 mRNA表达在高氧诱导组也明显高于正常对照组(P<0.01)。结论: OIR模型小鼠视网膜SDF-1表达增高,其促新生血管功能可能与CD14⁺细胞有关。     

玻璃体内移植骨髓基质细胞显著减少小鼠氧诱导视网膜病血管新生(英文)

目的:探索通过玻璃体内细胞移植预防和治疗早产儿视网膜病(retinopathy of prematurity,ROP)的可能途径。方法:获取成年大鼠骨髓基质细胞(marrow stromal cells,MSC),并连续传代。应用免疫组织化学和ELISA技术检测MSC中及MSC条件培养基(MSC-CM)中生长因子的表达。通过体外检测内皮细胞增殖、迁移和管腔形成确认MSC-CM的作用。将DiI标记的MSCs细胞移植入氧诱导视网膜病(oxygen induced retinopathy,OIR)模型小鼠玻璃体腔。应用免疫荧光技术检测神经或胶质细胞分布与分化标志。采用视网膜整装片ADP酶组织化学染色和视网膜前内皮血管细胞核计数方法评估新生血管的抑制作用。转染血管内皮生长因子(vascular endothelial growth factor,VEGF)干扰RNA质粒的MSCs验证VEGF的保护作用。结果:体外培养的MSCs表达VEGF,胰岛素生长因子(insulin-like growth factors,IGF)和神经生长因子(nerve growth factor,NGF)。MSC-CM促进体外培养内皮细胞的增殖,迁移和管型形成。发现眼内移植后,标记的MSCs聚集在视网膜前的玻璃体内,或者整合入视网膜,并表达胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)。吸入高氧前玻璃体内注射MSCs能显著缓解视网膜新生血管。体外和体内研究证实转染VEGF干扰RNA质粒的MSCs后其保护作用减弱。结论:在OIR早期移植MSCs能显著减少新生血管形成。VEGF等因子的旁分泌,可能在此过程发挥重要作用;通过细胞移植保护视网膜血管可以作为治疗ROP的潜在途径。     

新生小鼠吸入高氧视网膜的血管发育与胶质纤维酸性蛋白表达的变化

目的:研究新生小鼠吸入高氧视网膜病(ROP)过程中胶质纤维酸性蛋白(GFAP)表达的变化规律,探讨Müller细胞与血管发育的关系。方法:实验用生后7 d(P7)C57BL/6J小鼠。ROP模型组在75%氧环境中饲养。在P9、P12、P14、P17和P21等不同时间取眼球,分别用ADP酶组织化学染色方法显示视网膜血管发育及免疫组织化学方法标记视网膜GFAP的表达。结果:小鼠视网膜血管生后开始发育,P21基本成熟;吸高氧后从P14开始出现新生血管,在P17~P21达到高峰。模型鼠视网膜Müller细胞从P14起内侧突起开始表达GFAP,到P21已遍布细胞全层。结论:高氧可导致视网膜发育晚期大量血管新生,且与GFAP表达的变化规律相一致,提示Müller细胞与视网膜血管发育关系密切。     

血管生成素-2在早产儿视网膜病变动物模型中的表达及意义

目的研究血管生成素-2(angiopoietin-2,Ang-2)在高氧诱导的小鼠视网膜新生血管动物模型中的表达,探讨Ang-2在视网膜新生血管形成中的作用。方法高浓度氧诱导C57BL/6J小鼠建立视网膜缺血性病变动物模型。将20只新生小鼠随机分为高氧诱导组和正常对照组。将高氧诱导组小鼠置于氧气浓度为(75±2)%的密闭容器中饲养,5 d后将幼鼠取出置于正常环境中饲养,正常对照组幼鼠置于正常环境中饲养。两组幼鼠均于生后17天处死,用免疫组化和Real-time PCR的方法检测幼鼠视网膜Ang-2蛋白及mRNA表达情况。结果高氧诱导组幼鼠突破内界膜的新生血管内皮细胞数为25.68±2.61,明显高于正常对照组1.45±1.01,两组比较差异有统计学意义(P0.05)。高氧诱导组幼鼠Ang-2 mRNA的相对表达量是3.01±1.11,明显高于正常对照组1.47±0.53,两组比较差异有统计学意义(P0.05)。两组的Ang-2平均光密度值分别是121.25±8.61和75.45±7.87,两组比较差异有统计学意义(P0.05)。结论高氧诱导组幼鼠眼球中Ang-2表达明显增加,视网膜新生血管的形成显著增多,提示Ang-2在视网膜新生血管形成过程中可能发挥着重要作用。     

核运输因子2在糖尿病大鼠视网膜的时空表达及其意义

目的:探讨糖尿病大鼠视网膜中核运输因子2(NTF2)的时空表达变化及意义。方法:伊凡思蓝(EB)灌注铺片观察糖尿病大鼠视网膜血管分布和形态。逆转录-聚合酶链式反应(RT-PCR)检测与糖尿病大鼠不同时点鼠龄匹配的对照组(N2w,N1m,N3m,N6m)和糖尿病成模后2周、1月、3月、6月(D2w,D1m,D3m,D6m)大鼠视网膜中NTF2、血管内皮生长因子(VEGF)mRNA的表达。免疫组化法检测NTF2蛋白在视网膜中的表达和分布位置。结果:正常组大鼠可见在低背景荧光下视网膜血管对EB有很好的屏障作用,成模1月后糖尿病大鼠视网膜血管仅见背景荧光增强,成模3月后血管出现异常节段性扩张,局部血管周围EB渗漏。与糖尿病大鼠年龄匹配的正常大鼠视网膜NTF2和VEGF并未随时间延长而变化,mRNA表达稳定。糖尿病成模2周后开始,NTF2mRNA有轻度增高,并随病程的延长保持较高水平,病程达6个月时,NTF2表达开始回落,与正常大鼠基本一致。NTF2蛋白在正常大鼠及糖尿病大鼠视网膜中免疫组化均可以检出,主要分布在视网膜内层,以节细胞层、内核层为主。结论:NTF2mRNA水平在糖尿病大鼠视网膜中升高,主要分布在视网膜内层。NTF2很可能在糖尿病视网膜病变中起着一定的调控作用,其作用途径及机制可能与VEGF的作用通路有一定的联系。     

VEGF165转染大鼠血管内皮细胞对新生血管形成影响的实验研究

目的探讨血管内皮细胞生长因子（vascular endothelial growth factor，VEGF）基因与增强绿色荧光蛋白（enhanced green fluorescent protein，EGFP）共表达载体转染大鼠血管内皮细胞，植入大鼠体内，观察诱导新生血管情况，为移植组织诱导新生血管形成奠定基础。方法对质粒pIRES2-EGFP／VEGF，岱进行扩增、纯化，以脂质体法转染大鼠血管内皮细胞并植入肾被膜下。采用荧光显微镜检测增强绿色荧光蛋白在内皮细胞中的表达，用流式细胞仪检测转染效率。用RT-PCR检测VEGF mRNA的表达。免疫组化检测VEGF在内皮细胞中的表达。切取移植肾脏组织标本,HE染色观察组织形态学变化。结果荧光显微镜观察到实验组内皮细胞有特异性的EGFP表达。流式细胞仪分析转染效率为13．06％。实验组血管内皮细胞胞核和胞浆中均有VEGF表达。RT-PCR显示实验组大鼠血管内皮细胞中有人源化VEGF165基因在mRNA水平表达。移植后14d，实验组大鼠肾被膜下可见成团的新生毛细血管网形成，而对照组及空白转染组尽管血管内皮细胞仍存活，但未形成明显血窦。结论转染VEGF是促进内皮细胞早期（14d内）形成新生血管的有效途径。     

卵巢上皮性肿瘤组织中HIF-1α与VEGF的表达及意义

目的探讨卵巢上皮性肿瘤组织中缺氧诱导因子-1α（hypoxia inducible factor-1α,HIF-1α）的表达水平及其与血管内皮生长因子（vascularendothelial growth factor,VEGF）的关系。方法采用原位杂交和免疫组化S-P法检测66例卵巢上皮性肿瘤组织和正常卵巢组织中HIF-1αmRNA和VEGF蛋白的表达情况。结果在卵巢上皮癌和交界性卵巢肿瘤组织中HIF-1αmRNA的表达水平明显高于良性卵巢上皮性肿瘤和正常卵巢组织（P〈0．05）,而且与肿瘤的病理学分级有关（P〈0．05）。HIF-1αmRNA的表达与VEGF有相关性。结论HIF-1α对卵巢上皮癌的发生、发展具有重要作用,它可通过介导VEGF的表达促进肿瘤新生血管形成,从而进一步促进肿瘤的生长和转移。     

小鼠诱导性多能干细胞移植治疗宫内缺氧新生鼠脑损伤

目的:研究小鼠诱导性多能干细胞(iPSCs)移植对宫内缺氧新生鼠脑损伤的治疗作用及机制。方法:于孕14 d开始孕鼠置于动物缺氧培养箱中,制作胎鼠宫内缺氧模型。孕鼠分娩后新生鼠经侧脑室注入BrdU标记的iPSCs悬液移植组和PBS缺氧组,对照组不治疗,H-E染色观察脑组织形态学变化、八臂迷宫测试动物记忆功能、免疫组织化学检测脑BrdU阳性细胞和神经颗粒素(Ng)和神经元烯醇化酶(NSE)的表达、原位杂交检测血管内皮生长因子mRNA(VEGF mRNA)的表达。结果:移植组小鼠的学习记忆能力和脑皮质区细胞结构较缺氧组均明显改善;脑切片检出BrdU阳性细胞存在,缺氧组Ng和NSE阳性细胞表达较对照组显著减少,而VEGF mRNA的表达较对照组显著增加;移植组Ng、NSE和VEGF mRNA表达均较缺氧组显著增加。结论:小鼠iPSCs移植于宫内缺氧的新生小鼠脑中,可减轻缺氧神经元的损伤和提高学习能力,其机制可能通过上调VEGF mRNA和Ng的表达有关。     

辛伐他汀对成骨细胞血管内皮生长因子的表达和颅骨内血管新生的影响

目的 通过观察辛伐他汀对体外培养成骨细胞血管内皮生长因子(VEGF)的表达及对颅骨血管新生的影响,探讨其促进骨形成的作用机制.方法 将离体培养颅骨成骨细胞与辛伐他汀作用24h后,提取RNA行RT-PCR,半定量测定细胞VEGF mRNA的表达,免疫细胞化学染色吸光度测定VEGF蛋白表达水平;小鼠头皮下局部注射辛伐他汀和空白溶剂25μl,连续5d,1个月后取出颅骨做病理检查.结果 辛伐他汀可增加成骨细胞VEGF的mRNA和蛋白的表达.局部用药后可见小鼠颅骨增厚,骨质内部有新生血管出现.结论 促进成骨细胞VEGF的表达及骨内血管新生,是他汀类药物促进骨形成的作用机制之一.     

MCP-1及其受体在wAMD小鼠模型视网膜中的表达及作用机制

目的探讨单核细胞趋化因子-1(monocyte chemoattractant protein-1,MCP-1)及其受体CCR2在湿性年龄相关性黄斑变性(wet age-related macular degeneration,wAMD)小鼠模型视网膜中的表达及作用机制。方法制备wAMD小鼠模型,摘取眼球制作冷冻切片,使用MCP-1和CCR2单克隆抗体行免疫荧光检测。使用CD11b和CD68单克隆抗体分别与CCR2抗体进行免疫荧光共表达研究以检测CCR2阳性细胞的来源。制备视网膜的总蛋白和总mRNA提取物,经RT-PCR和Western blot检测视网膜中MCP-1及其受体CCR2 mRNA和蛋白的表达。结果正常对照组小鼠视网膜中无明显的MCP-1表达,wAMD小鼠模型中视网膜色素上皮(retinal pigment epithelium,RPE)层下有显著的新生血管网形成,且RPE层连续性被破坏,其中RPE细胞有明显的MCP-1表达上调。正常对照组小鼠视网膜中无明显的CCR2的表达,wAMD模型小鼠的视网膜中CCR2阳性细胞显著增加。与正常对照组小鼠相比,wAMD模型小鼠眼内MCP-1和CCR2的蛋白和mRNA表达明显上调。免疫荧光共表达结果显示CCR2与CD11b有显著的共表达,双阳性细胞集中在RPE层和视网膜外层;而CCR2与CD68无明显的共表达。结论 MCP-1及其受体可能与wAMD小鼠模型视网膜脉络膜新生血管(choroidal neovascularization,CNV)的形成及其炎症机制相关。     

Expression of thrombospondin-1 in ischemia-induced retinal neovascularization

Thrombospondin-1 is an extracellular matrix protein that inhibits endothelial cell proliferation, migration, and angiogenesis. This study was performed to investigate the role of thrombospondin-1 in ischemic retinal neovascularization. In a murine model of retinal neovascularization, thrombospondin-1 mRNA was increased from postnatal day 13 (P13), with a threefold peak response observed on P15, corresponding to the time of development of retinal neovascularization. Prominent expression of thrombospondin-1 was observed in neovascular cells, specifically, cells adjacent to the area of nonperfusion. It has been suggested that vascular endothelial growth factor (VEGF) plays a major role in ischemia-induced retinal neovascularization of this model, so we studied the effects of VEGF on thrombospondin-1 expression. In bovine retinal microcapillary endothelial cells, VEGF induced a biphasic response of thrombospondin-1 expression; VEGF decreased thrombospondin-1 mRNA 0.41-fold after 4 hours, whereas it increased, with a threefold peak response, after 24 hours. VEGF-induced endothelial cell proliferation was completely inhibited by exogenous thrombospondin-1 and increased by 37.5% with anti-thrombospondin-1 antibody. The present findings suggest that, in the ischemic retina, retinal neovascular cells increase thrombospondin-1 expression, and VEGF may stimulate endogenous thrombospondin-1 induction, which inhibits endothelial cell growth. VEGF-mediated thrombospondin-1 induction in ischemia-induced angiogenesis may be a negative feedback mechanism.     

Bone marrow-derived monocyte lineage cells recruited by MIP-1β promote physiological revascularization in mouse model of oxygen-induced retinopathy

Recent clinical observations have indicated that vascular endothelial growth factor (VEGF) is a key factor that stimulates the development of preretinal pathological neovascularization (NV). However, it has not been established how intraretinal physiological revascularization of hypoxic avascular areas is regulated. Our earlier study on the gene expression profile of hypoxic retinas in a mouse model of oxygen-induced retinopathy (OIR) showed that macrophage inflammatory protein-1β (MIP-1β) was the most upregulated protein. The purpose of this study was to investigate the role played by MIP-1β in recruiting bone marrow-derived monocyte lineage cells (BM-MLCs) in a mouse model of OIR. Our results showed that MIP-1β was upregulated, and its receptor, CCR5, was expressed in BM-MLCs in the hypoxic inner retina. Neutralizing Ab against MIP-1β reduced the infiltration of BM-MLCs into the OIR retinas and increased the avascular area and preretinal neovascular tufts. A very strong significant correlation was found between the area of the preretinal neovascular tufts and the avascular area, regardless of the extent of BM-MLC infiltration into the OIR retinas. Additional treatment with VEGF-A-neutralizing Ab showed that the MIP-1β-regulated pathological NV strongly depended on VEGF-A, which was probably secreted by the hypoxic avascular retinas. These results indicate that MIP-1β is involved in the recruitment of BM-MLCs, which have a significant role in the physiological revascularization of hypoxic avascular retinas. Overall, these findings indicate that the MIP-1β induction of BM-MLCs might possibly be used to promote intraretinal revascularization and thus prevent the abnormal NV in ischemic vision-threatening retinal diseases.     

Interleukin-18 regulates pathological intraocular neovascularization

Recently, the proinflammatory cytokine IL-18 has been shown to have a role in angiogenesis. This study aimed to elucidate its role in abnormal neovascularization (NV) in an oxygen-induced retinopathy (OIR) mouse model of the retinopathy seen in human premature newborns. IL-18 was constitutively expressed in the retina in C57BL/6 mice, but expression transiently dropped on Day 17 after birth in mice exposed to 75% oxygen for 5 days between Days 7 and 12. Coincident with the IL-18 reduction in oxygen-treated mice, vascular endothelial growth factor was expressed in the retina, and OIR developed. By Day 24, NV in the retina had regressed to normal levels. By contrast, IL-18 knockout mice, exposed to elevated oxygen concentrations, developed more severe OIR on Day 17, and it is important that this persisted until Day 24. This suggested that IL-18 negatively regulated retinal NV. To investigate this further, we administrated recombinant IL-18 to C57BL/6 mice during the development of OIR but found no significant inhibition of retinopathy. However, when IL-18-binding protein was administered during the OIR recovery phase to neutralize endogenous IL-18, OIR was still apparent on Day 24. We therefore concluded that IL-18 regulates pathogenic retinal NV by promoting its regression rather than inhibiting its development. This suggests some useful, new approaches to treating retinopathy in humans.     

Inhibition of tumor necrosis factor-alpha improves physiological angiogenesis and reduces pathological neovascularization in ischemic retinopathy

The present study was undertaken to test whether inhibition of the proangiogenic inflammatory cytokine tumor necrosis factor (TNF)-alpha can modulate retinal hypoxia and preretinal neovascularization in a murine model of oxygen-induced retinopathy (OIR). OIR was produced in TNF-alpha-/- and wild-type (WT) control C57B6 neonatal mice by exposure to 75% oxygen between postnatal days 7 and 12 (P7 to P12). Half of each WT litter was treated with the cytokine inhibitor semapimod (formerly known as CNI-1493) (5 mg/kg) by daily intraperitoneal injection from the time of reintroduction to room air at P12 until P17. The extent of preretinal neovascularization and intraretinal revascularization was quantified by image analysis of retinal flat-mounts and retinal hypoxia correlated with vascularization by immunofluorescent localization of the hypoxia-sensitive drug pimonidazole (hypoxyprobe, HP). HP adducts were also characterized by Western analysis and quantified by competitive enzyme-linked immunosorbent assay. TNF-alpha-/- and WT mice showed a similar sensitivity to hyperoxia-induced retinal ischemia at P12. At P13 some delay in early reperfusion was evident in TNF-alpha-/- and WT mice treated with semapimod. However, at P17 both these groups had significantly better vascular recovery with less ischemic/hypoxic retina and preretinal neovascularization compared to untreated retinopathy in WT mice. Immunohistochemistry showed deposition of HP in the avascular inner retina but not in areas underlying preretinal neovascularization, indicating that such aberrant vasculature can reduce retinal hypoxia. Inhibition of TNF-alpha significantly improves vascular recovery within ischemic tissue and reduces pathological neovascularization in OIR. HP provides a useful tool for mapping and quantifying tissue hypoxia in experimental ischemic retinopathy.     

氧环境对血管内皮生长因子、色素上皮衍生因子的影响及其与血管发育的关系

目的：研究视网膜发育过程中血管内皮生长因子(VEGF)和色素上皮衍生因子(PEDF)所起的调节作用及其机制。方法：C57BL/6J 小鼠从出生后7～12 d 饲养于75%氧环境,分别用抗 VEGF、抗 PEDF 和抗 CD31抗体作免疫组织化学标记视网膜切片。结果：持续处于高氧环境时,VEGF 表达处于低水平而 PEDF 快速上升,血管生长减缓。高氧处理5 d 后回到普通环境,VEGF 的表达迅速上升而 PEDF 却逐渐减少,出现了一过性的血管快速增长现象。结论：氧含量变化可调节 VEGF 和 PEDF 表达,参与视网膜血管发育。     

Generation of retinal cells in the wallaby, Setonix brachyurus (quokka)

We have examined the generation of retinal cells in the wallaby, Setonix brachyurus (quokka). Animals received a single injection of tritiated thymidine between postnatal days 1-85 and retinae were examined at postnatal day 100. Retinae were sectioned, processed for autoradiography and stained with Cresyl Violet. Ganglion cells were labelled by injection of horseradish peroxidase into the optic tracts and primary visual centres. Other cells were classified according to their morphology and location. Retinal cell generation takes place in two phases. During the first phase, which concludes by postnatal day 30, cells destined to lie in all three cellular layers of the retina are produced. In the second phase, which starts by postnatal day 50, cell generation is almost entirely restricted to the inner and outer nuclear layers. Cells produced in the first phase are orthotopic and displaced ganglion cells, displaced and orthotopic amacrine cells, horizontal cells and cones. Glia in the ganglion cell layer, orthotopic amacrine cells, bipolar and horizontal cells. Muller glia, and rods are generated in the second phase. Cells became heavily labelled with tritiated thymidine in the central retina before postnatal day 7, over the entire retina (panretinal) by postnatal day 7 and from postnatal day 18, only in the periphery. The second phase of cell generation is initiated at P50, in a region extending from the optic nerve head to mid-temporal retina. Subsequently, cells are generated in annuli, centred on mid-temporal retina, which are seen at progressively more peripheral locations. Therefore, cell addition to the inner and outer nuclear layers continues for longer in peripheral than in mid-temporal retina. We suggest that such later differential cell addition to the inner and outer nuclear layers contributes to an asymmetric increase in retinal area. This non-uniform growth presumably results in more expansion of the ganglion cell layer peripherally than in mid-temporal retina and may play a role in establishing density gradients of ganglion cells.     

The 67-kd laminin receptor is preferentially expressed by proliferating retinal vessels in a murine model of ischemic retinopathy.

Endothelial cell association with vascular basement membranes is complex and plays a critical role in regulation of cell adhesion and proliferation. The interaction between the membrane-associated 67-kd receptor (67LR) and the basement membrane protein laminin has been studied in several cell systems where it was shown to be crucial for adhesion and attachment during angiogenesis. As angiogenesis in the pathological setting of proliferative retinopathy is a major cause of blindness in the Western world we examined the expression of 67LR in a murine model of hyperoxia-induced retinopathy that exhibits retinal neovascularization. Mice exposed to hyperoxia for 5 days starting at postnatal day 7 (P7) and returned to room air (at P12) showed closure of the central retinal vasculature. In response to the ensuing retinal ischemia, there was consistent preretinal neovascularization starting around P17, which persisted until P21, after which the new vessels regressed. Immunohistochemistry was performed on these retinas using an antibody specific for 67LR. At P12, immunoreactivity for 67LR was absent in the retina, but by P17 it was observed in preretinal proliferating vessels and also within the adjacent intraretinal vasculature. Intraretinal 67LR immunoreactivity diminished beyond P17 until by P21 immunoreactivity was almost completely absent, although it persisted in the preretinal vasculature. Control P17 mice (not exposed to hyperoxia) failed to demonstrate any 67LR immunoreactivity in their retinas. Parallel in situ hybridization studies demonstrated 67LR gene expression in the retinal ganglion cells of control and hyperoxia-exposed mice. In addition, the neovascular intra- and preretinal vessels of hyperoxia-treated P17 and P21 mice labeled strongly for 67LR mRNA. This study has characterized 67LR immunolocalization and gene expression in a murine model of ischemic retinopathy. Results suggest that, although the 67LR gene is expressed at high levels in the retinal ganglion cells, the mature receptor protein is preferentially localized to the proliferating retinal vasculature and is almost completely absent from quiescent vessels. The differential expression of 67LR between proliferating and quiescent retinal vessels suggests that this laminin receptor is an important and novel target for future chemotherapeutic intervention during proliferative vasculopathies.