血管内皮生长因子在氧诱导小鼠新生血管中的表达及意义

目的探讨血管内皮生长因子（VEGF）在小鼠视网膜新生血管中的表达及意义。方法对新生c57BL／6N小鼠高氧后相对低氧饲养，诱导产生视网膜新生血管。在出生后12d、17d摘除眼球，应用RT-PCR，Western Blot以及视网膜血管荧光灌注造影技术检测全视网膜VEGF mRNA、蛋白表达水平以及视网膜新生血管的发生程度。结果视网膜血管造影显示高氧造成血管发育受限，相对低氧后产生新生血管。伴随新生血管的发生，VEGF mRNA升高2．3倍；VEGF蛋白含量也升高7．3倍。结论VEGF表达改变与新生血管发生成正相关，其升高也是造成病理性视网膜新生血管发生的机制之一。减少内源性VEGF表达可能成为治疗视网膜新生血管的新方法。     

血管内皮生长因子与大鼠角膜新生血管生长及退化的相关性实验研究

目的 观察大鼠碱烧伤后角膜新生血管（corneal neovascularization,NCV)的生长及退化过程和角膜中血管内皮生长因子（vascular endothelial growth factor,VEGF)mRNA的变化，探讨两者间的相互作用。方法 建立大鼠角膜碱烧伤新生血管模型，利用角膜灌注和照相方法对CNV进行观察。在不同时间点提取角膜的总RNA，并用半定量逆转录聚合酶链式反应（RT－PCR）检测VEGF mRNA。应用结膜下注射地塞米松治疗CNV，并观察其对VEGF表达的调节作用。结果 大鼠角膜碱烧伤后角膜新生血管的生长过程可分为3个阶段：（1）角膜新生血管的初期阶段（烧伤后2d内）；（2）角膜新生血管的增长阶段（烧伤后3－10d）；（3）新生血管的退化阶段（烧伤2周后）。实验发现VEGF mRNA在烧伤后24h达到高峰，是正常角膜的5．3倍；在烧伤后第4天，VEGF mNRA水平为正常时1倍；第7天时，VEGF mRNA下降至正常。地塞米松组CNV生长与VEGF mRNA的表达均受到抑制，在烧伤后24h VEGF的表达是正常时的3．24倍，抑制率为38．8％；烧伤后4d，较对照组VEGF的表达下降了16．2％。地塞米松组CNV面积抑制率分别是对照组的21．7％（烧伤后第4天）和23．7％（烧伤后第7天）。结论 VEGF mRNA的升高及降低同CNV的发生及退化关系密切，激素对角膜新生血管的抑制与对VEGF表达的抑制相关。     

氧诱导视网膜病变鼠模型血管内皮 生长因子mRNA的表达

目的分析氧诱导视网膜病变动物模型血管内皮生长因子（VEGF）基因的调节规律，阐明早产儿视网膜病变（ROP）新生血管形成的可能机制。方法将36只7 d 龄C₅₇BL/6J幼鼠暴露在（75±2）% 浓度的高氧状态下5 d，随后在正常氧环境下5 d，作为氧诱导模型组；另24只同日龄幼鼠作为正常对照组。采用荧光素血管灌注及视网膜铺片法观察视网膜血管形态；半定量逆转录-聚合酶链反应(RP-PCR)观察各组VEGF mRNA的变化。结果氧诱导模型的视网膜血管形态特征为高氧状态下表层和深层血管的中心区出现无灌注，相对低氧状态下2 d后开始出现新生血管，其部位在中周部。RF-PCR结果显示，VEGF的表达与眼内新生血管的发生存在明确的时空对应关系，即高氧状态下，VEGF mRNA转录下降，相对低氧状态下，VEGF mRNA过度转录。结论缺氧是视网膜新生血管发生的主要原因；高氧之后的相对低氧使VEGF表达增加，可能会降低ROP新生血管的发生。(中华眼底病杂志,2005,21:292-295)     

轴突导向因子-1 mRNA在氧诱导血管增生性视网膜病变中的表达

目的研究高氧诱导的视网膜新生血管模型鼠中轴突导向因子-1（Netrin-1）mRNA的表达差异。方法采用高氧诱导的方法制作鼠视网膜新生血管模型;运用荧光造影视网膜铺片及视网膜切片苏木精-伊红染色观察视网膜新生血管的形态。于出生后第12、14、17d取小鼠视网膜,采用RT-PCR测定Netritt-1mRNA的表达水平。结果模型组视网膜铺片及组织切片可见大量视网膜新生血管形成。出生后12d,模型组与正常组视网膜组织中Netrin-1mRNA表达水平无明显差异;出生后14d,模型组视网膜组织中Netrin-1mRNA表达水平明显上调;出生后17d模型组视网膜组织中Netrin-1mRNA表达水平仍高于正常组。结论模型鼠视网膜新生血管发生过程中,持续缺氧的视网膜组织可能从转录水平增加Netrin-1的表达,从而诱导视网膜新生血管的发生。     

PEDF和VEGF mRNA在实验性脉络膜新生血管组织中的表达

目的 研究血管内皮生长因子(vessel endothelial growth factor，VEGF)和色素上皮衍生因子(pigment epithelium derived factor，PEDF)在实验性小鼠脉络膜新生血管(choroidal neowascularization,CNV)组织中的表达情况。探讨二者在CNV形成过程中所起的作用。方法 用半导体激光诱导小鼠CNV模型。分别于激光后1、3、7d、2和3周时取出眼球，采用原位杂交方法检测CNV组织中VEGF和PEDF mRNA的表达情况。结果 VEGF和PEDF mRNA在激光诱导的小鼠CNV组织形成过程中均有显著表达。激光光凝早期二者的表达均增高，但VEGF mRNA的表达升高更显著。激光照射后3和7d时．VEGF mRNA的表达即达到高峰，阳性率分别为26．05％和27．92％，而PEDF mRNA的阳性表达率分别为21．13％和23．55％．2周时，VEGF mRNA表达开始下降，约为23．95％，而PEDF mRNA的表达则达到高峰,为29．19％,光凝后3周时，二者的表达均下降，但PEDF mRNA的表达仍高于VEGF mRNA的表达，分别为24．87％和21．93％．结论 VEGF和PEDF mRNA明显表达于实验性小鼠CNV组织中。2者表达失衡可能在CNV的形成过程中起到调控作用。     

血管内皮生长因子在新生小鼠视网膜的表达

目的 研究血管内皮生长因子（vascular endothelial growth factor,VEGF)与新生小鼠视网膜血管系统形成的内在联系，方法 分别于小鼠出生后3d,1、2、4周以免疫组化观察VEGF在视网膜的表达，并与视网膜铺片和光镜结果相对照。结果 小鼠出生后视网膜血管系统由视盘处呈放射状穿出，逐渐由后极部向周边部，视网膜病理切片显示；出生后3d时，视网膜只有2层，即神经节细胞层和神经母细胞层，内层毛细血管仅限于视网膜后极及中周部，7d时外丛状层形成，出生后14d，视网膜外层毛细血管发育基本完成，出生后28d，视网膜与14d时大致相似，VEGF免疫组化结果显示；出生后3d，阳性信号位于神经节细胞层和神经母细胞层内，外缘，7d时，VEGF明显表达在神经节细胞层，外丛状层和几乎全层内核层，出生后14d及28d。当视网膜血管系统发育基本完成时，VEGF阳性细胞数量和强度都明显减少和减弱。结论 本研究提示，VEGF的表达在空间和时间上与视网膜血管形成密切相关，VEGF的存在对于小鼠视网膜血管系统的形成及维持正常生理功能可能至关重要。     

实验性脉络膜新生血管中环氧合酶-2、血管内皮生长因子和基质金属蛋白酶-2的表达

目的研究实验性脉络膜新生血管（CNV）大鼠中环氧合酶-2（COX-2）、血管内皮生长因子（VEGF）和基质金属蛋白酶-2（MMP-2）的表达,并进一步探讨其在CNV中的作用机制及相互关系。方法应用氪红激光光凝视网膜的方法诱导制作BN大鼠的CNV模型,分别选取并制作无任何干预的对照组和实验组光凝后第3、7、14、21、30天的＂最大CNV膜＂切片,采用免疫组织化学技术检测COX-2、VEGF和MMP-2在视网膜和CNV膜中的表达。应用HPIAS-1000型高清晰度彩色病理图文分析系统测定COX-2、VEGF和MMP-2阳性染色的平均灰度值。结果 COX-2、VEGF和MMP-2在正常视网膜和脉络膜中呈弱表达,视网膜光凝后,COX-2、VEGF和MMP-2在视网膜和CNV膜中的表达在7～14 d逐渐增强,21 d时三者的表达强度均达到高峰,之后略减弱。视网膜光凝后7、14、21、30 d,实验组COX-2、VEGF和MMP-2的免疫组织化学染色平均灰度值与对照组相比差异均有统计学意义（P〈0.05）。COX-2的表达强度与VEGF和MMP-2的变化均呈正相关（r=0.967,P=0.007;r=0.966,P=0.007）。结论激光诱导的实验性CNV中COX-2、VEGF及MMP-2的表达随着时间的延长呈动态变化,CNV局部炎症诱导的COX-2表达可能是VEGF和MMP-2的上游调节因子。     

激光光凝对大鼠视网膜色素上皮衍生因子表达的影响

目的 研究眼底视网膜激光光凝后大鼠视网膜色素上皮衍生因子（PEDF）蛋白表达的变化。方法 雄性BN大鼠40只，右眼为实验眼，左眼为对照眼，眼底行全视网膜光凝，分别于光凝后6h、24h和3d、7d摘出眼球，行免疫组织化学检测和酶联免疫吸附测定。结果 光凝后PEDF蛋白阳性信号可见于激光光斑内视网膜神经节细胞层、内颗粒层、外颗粒层及色素上皮层。激光光凝后6h视网膜组织中PEDF蛋白表达升高，24h时达到高峰（P〈0．01），后逐渐下降，1周时仍高于正常（P〈0.05）。结论 视网膜组织中PEDF蛋白可能通过其抗新生血管活性，对激光光凝后视网膜新生血管的消退发挥重要作用。     

VEGF siRNA抑制鼠视网膜新生血管的实验研究

背景血管内皮生长因子（VEGF）在视网膜新生血管的发生过程中发挥重要作用,抑制VEGF是目前视网膜新生血管治疗和预防研究的热点。VEGF小片段干扰RNA（VEGFsiRNA）在抗肿瘤新生血管的研究中已经取得了显著疗效,但对于视网膜新生血管的干预作用报道较少。目的研究VEGF siRNA对鼠视网膜新生血管的抑制作用。方法48只新生C57BL／6J幼鼠采用随机数字表法随机分为正常对照组、模型对照组、空载体组和VEGF siRNA质粒转染组,每组12只幼鼠。7日龄C57BL／6J幼鼠36只及其母鼠置于密闭的氧舱5d建立缺氧性新生血管模型,其中12只幼鼠不进行质粒转染作为模型对照组,其余24只鼠玻璃体腔内注射脂质体（LF2000）包裹的空载体质粒或VEGF siRNA表达质粒。待小鼠19日龄时获取小鼠眼球并分离视网膜,用苏木精一伊红染色法计数各组小鼠视网膜新生血管内皮细胞核的数目,用实时荧光定量聚合酶链反应（tea-time PCR）法检测视网膜中VEGF mRNA的表达,并应用免疫荧光技术检测小鼠视网膜中VEGF蛋白的表达。结果正常对照组、模型对照组、空载体组和VEGFsiRNA质粒转染组19日龄小鼠视网膜突破内界膜的内皮细胞细胞核数目分别为（0．19±0．09）个、（24．89±2．03）个、（23．65±2．15）个和（8．83±1．12）个,表明VEGFsiRNA质粒转染组小鼠的新生血管内皮细胞数明显低于模型对照组和空载体组,差异均有统计学意义（q=5．67、q=4．97,P〈0．01）。Real-time PCR检测表明,正常对照组小鼠视网膜中仅见弱的VEGF mRNA表达,而模型对照组与空载体组VEGF mRNA表达量为正常对照组的52．3倍和36．7倍,VEGF siRNA质粒转染组小鼠视网膜VEGF mRNA的表达量为正常对照组的3．5倍,明显低于模型对照组与空载体组。VEGF siRNA对VEGF mRNA的抑制率为43．39％。免疫荧光染色显示,正常对照组小鼠VEGF蛋白呈弱阳性表达,模型对照组和空载体组VEGF小鼠视网膜中VEGF蛋白表达呈强阳性,VEGF siRNA质粒转染组VEGF蛋白表达明显减弱。结论玻璃体腔注射VEGF siRNA表达质粒可有效抑制C57BL／6J小鼠氧诱导视网膜病变模型新生血管的形成。     

血管内皮生长因子干扰RNA对鼠视网膜中血管内皮生长因子mRNA表达的抑制作用

目的 研究血管内皮生长因子（vascular endothelial cell growth factor,VEGF）小片段干扰RNA（small interference RNA,siRNA）对鼠视网膜VEGF mRNA的抑制作用,探讨其对视网膜新生血管治疗的可行性.方法 体外培养人鼻咽癌细胞（CNE-2Z）,分成正常氧培养组（20% O2）和低氧培养组（1% O2）.采用脂质体（LF 2000）将VEGF siRNA转染两组细胞,RT-PCR检测VEGF mRNA的表达,确立VEGF siRNA对VEGFmRNA的抑制效率.然后,建立高浓度氧（75%）诱导的C57BL./6J小鼠视网膜新生血管动物模型,以脂质体为载体,将VEGF siRNA重组质粒注射到鼠玻璃体腔内,RT-PCR检测视网膜组织中VEGF mRNA的表达水平.结果 正常氧培养的CNE-2Z细胞有VEGF mRNA表达,低氧状态下VEGFmRNA表达增多,两者之间差异有显著性（P＜0.01）;与未转染组和转染空载体组相比,在正常氧和低氧状态下,VEGFsiRNA均能明显抑制VEGFmRNA的表达（P＜0.01）;正常氧状态下VEGF siRNA的抑制效率比低氧状态高.高浓度氧诱导的C57BL/6J小鼠视网膜新生血管动物模型中,玻璃体腔注射VEGF siRNA组视网膜组织中VEGF mRNA表达明显下降（P＜0.01）.结论 VEGF特异的siRNA能有效地抑制人鼻咽癌细胞CNE-2Z和C57BL/6J 小鼠视网膜新生血管动物模型视网膜中VEGF mRNA的表达.     

Expression of pigment epithelium-derived factor in normal adult rat eye and experimental choroidal neovascularization

PURPOSE: Pigment epithelium-derived factor (PEDF) is a protein produced by the retinal pigment epithelial (RPE) cells. Recent studies have implicated PEDF in activities that are inhibitory to angiogenesis. In this study, the expression of PEDF was investigated in normal rat eyes and in eyes with experimentally induced choroidal neovascularization and compared with the expression of vascular endothelial growth factor (VEGF). METHODS: Choroidal neovascularization was induced by laser photocoagulation in rat eyes. At intervals of up to 2 weeks after photocoagulation, the eyes were removed and prepared for in situ hybridization and immunohistochemical study. In situ hybridization was performed with digoxigenin-labeled PEDF riboprobes. Protein expression of PEDF and VEGF was studied immunohistochemically. RESULTS: In normal adult rat eyes, PEDF mRNA was observed mainly in the corneal epithelial and endothelial cells, lens epithelial cells, ciliary epithelial cells, retinal ganglion cells, and the RPE cells. During the development of choroidal neovascularization, PEDF mRNA, PEDF protein, and VEGF protein were strongly detected in many cells within the laser lesions at 3 days after photocoagulation, after which levels gradually declined. However, PEDF was still expressed in the RPE cells that proliferated and covered the neovascular tissues at 2 weeks, whereas VEGF protein was weakly expressed in endothelial cells in choroidal neovascularization. CONCLUSIONS: PEDF is expressed in different cell types of normal rat eyes. The expression of PEDF was detected in the choroidal neovascular tissues induced by photocoagulation, and these findings suggest that PEDF may modulate the process of choroidal neovascularization.     

Matrix metalloproteinase (MMP) expression in experimental choroidal neovascularization

PURPOSE: Matrix metalloproteinases (MMP) are a family of proteolytic enzymes that degrade basement membrane and extracellular matrix proteins. To gain information on the possible role of MMPs in choroidal neovascularization (CNV), we have analyzed the mRNA expression of MMP-2 and MMP-9, two forms of MMPs implicated in ocular neovascularization, in a rat model. METHODS: Choroidal neovascularization was induced in pigmented rats by krypton laser photocoagulation of the fundus whereafter eyes were enucleated at 1, 3, 5, 7, 10 and 60 days. Antisense and sense riboprobes were generated using DNA complementary to MMP-2 and MMP-9, and mRNA expression was analyzed using in situ hybridization. RESULTS: In the untreated eyes MMP-2 mRNA expression was weakly detected in cells within the choroid. In laser-treated eyes MMP-2 mRNA expression was markedly increased and mainly localized to macrophage-like and retinal pigment epithelial (RPE)-like cells invading the choroid, subretinal space and inner retina. This increase in MMP-2 mRNA expression peaked at day 10 whereafter a decline was detected. MMP-9 mRNA expression was low in untreated eyes and did not increase following laser treatment. CONCLUSION: The results show that MMP-2 mRNA expression is increased in experimental CNV, and support of a role for MMP-2 in the development of CNV in age-related macular degeneration.     

Neovascularization in the anterior segment of the rabbit eye by experimental anterior ischemia

PURPOSE: To investigate the effects of anterior ischemia accompanied by neither retinal nor choroidal ischemia on the anterior segment of the eye. METHODS: Both long posterior ciliary arteries in the right eye of 14 rabbits were directly cauterized with an electric coagulator. The eyes were enucleated 1, 2, 4, 7, 9 or 14 days after cauterization, then fixed with 4% paraformaldehyde. Semi-thin sections were studied by light microscopy. Several sections were stained with Griffonia simplicifolia lectin, which bound specifically to mammalian vascular endothelium. Other specimens were examined immunohistochemically for vascular endothelial growth factor (VEGF) protein. The tissue specimens of the first postoperative day were studied for expression of VEGF mRNA by in situ hybridization. RESULTS: Atrophy of the iris and ciliary body was seen after the second postoperative day. Corneal neovascularization appeared after 7 days. Neovascularization on the anterior surface of the iris and in the trabecular meshwork was detected after the ninth postoperative day. The proliferative tissues with newly formed vessels obstructed the iridocorneal angle 14 days after the treatment. There was no histological change in either the retina or choroid. Immunohistochemically, VEGF protein was detected in the epithelial and vascular cells of the iris on the first and fourth postoperative day. Expression of VEGF mRNA was detected in the epithelial cells of the ciliary body on the day following the treatment. CONCLUSIONS: Anterior segment ischemia, when unaccompanied by retinal ischemia, causes neovascularization in the cornea, iris and trabecular tissue.     

Inhibition of experimental choroidal neovascularization by overexpression of tissue inhibitor of metalloproteinases-3 in retinal pigment epithelium cells

PURPOSE: To evaluate the feasibility of introducing exogenous tissue inhibitor of metalloproteinases-3 gene into the rat retinal pigment epithelium using hemagglutinating virus of Japan liposomes and to assess the effect of tissue inhibitor of metalloproteinases-3 overexpression in retinal pigment epithelium cells on the formation of experimental choroidal neovascularization. METHODS: Hemagglutinating virus of Japan liposomes containing hemagglutin epitope-tagged tissue inhibitor of metalloproteinases-3 gene were injected into the subretinal space in rat eyes. Localization of oligonucleotides was evaluated by fluorescence microscopy. Exogenous tissue inhibitor of metalloproteinases-3 mRNA expression was assessed by reverse transcribed polymerase chain reaction. Exogenous tissue inhibitor of metalloproteinases-3 protein expression was visualized by immunostaining with monoclonal antibody 12CA5 against the hemagglutin epitope. Three days after transfection of tissue inhibitor of metalloproteinases-3 gene into retinal pigment epithelium cells, intense laser photocoagulation was performed and the incidence of choroidal neovascularization was assessed by fluorescein fundus angiography. RESULTS: Exogenous tissue inhibitor of metalloproteinases-3 mRNA expression in the choroid and retina was detected on day 3. The efficiency of tissue inhibitor of metalloproteinases-3 gene transfection into retinal pigment epithelium cells was greatest on day 7 and decreased gradually thereafter. The incidence of choroidal neovascularization in tissue inhibitor of metalloproteinases-3 gene-transfected eyes was markedly decreased compared with controls. CONCLUSIONS: This study shows that tissue inhibitor of metalloproteinases-3 gene can be transferred into rat retinal pigment epithelium using the hemagglutinating virus of Japan-liposome method and that tissue inhibitor of metalloproteinases-3 gene overexpression can inhibit development of experimental choroidal neovascularization. This method may represent a future treatment modality for human macular degeneration associated with choroidal neovascularization.     

恒河猴经瞳孔温热疗法与热休克蛋白相关研究

目的探讨恒河猴经瞳孔温热疗法（transpupillary thermotherapy，TTT）治疗后视网膜和脉络膜组织热休克蛋白70（heat shock protein 70，HSPT0）表达。方法利用恒河猴做动物模型。于1TIrr治疗后不同时间点（1h、1d、1周、2周、1月、4月）摘除双眼固定。应用免疫组化技术，分析TTT治疗对猴眼视网膜和脉络膜组织HSP70的影响。结果TTT治疗后，于1d起，在强反应光斑边缘视网膜和脉络膜有HSP70的表达，4个月时仍有弱表达。弱反应光斑1d时，在视网膜全层及脉络膜均有HSP70表达，4个月时消失。同时,TTT治疗可以引起视网膜不同程度组织病理学的损害。结论TTT可以引起视网膜、脉络膜组织病理学损害。局部温度的升高会诱导视网膜、脉络膜内源性HSP70的产生，并且这种表达在激光治疗后1～4个月的猴眼中仍可以存在。     

血管内皮生长因子及其受体在实验性脉络膜新生血管中的表达

目的 探讨血管内皮生长因子(VEGF)及其FLK1受体在氪激光诱导的棕色挪威(BN)大鼠脉络膜新生血管(CNV)中的表达。方法 应用氪激光对30只雄性BN大鼠实验眼进行视网膜光凝,创建CNV模型,分别于光凝后3、7、14、21、28及56 d行荧光素眼底血管造影(FFA),处死大鼠后摘除眼球,制作组织病理学标本观察,原位杂交检测VEGFmRNA,免疫组化检测VEGF和FLK1受体。结果 正常BN大鼠视网膜神经节细胞层、内核层、色素上皮层、视网膜及脉络膜血管内皮细胞中均表达VEGFmRNA。实验眼光凝后3 d,光凝区视网膜神经节细胞层、内核层、外核层缺损区、视网膜及脉络膜血管内皮细胞均表达VEGFmRNA,此时视网膜下未形成CNV;3-21 d视网膜内VEGFmRNA表达水平逐渐下降(P<0.01);21 d与28 d和56 d比较,VEGFmRNA表达水平差异无显著意义(P>0.05)。光凝后7 d,FFA检查可见光凝区有圆盘状荧光素渗漏。病理切片可见视网膜下形成CNV,CNV中VEGFmRNA表达阳性;7～21 d,CNV中VEGFmRNA阳性染色面积及吸光度(A)值逐渐增加(P<0.01);21 d后VEGFmRNA表达水平差异无显著意义(P>0.05)。正常视网膜和脉络膜血管内皮细胞及视网膜神经节细胞层FLK1受体表达阳性;光凝后7 d,CNV中FLK1受体表达阳性;随CNV的增生,FLK1受体阳性染色面积及A值逐渐增加(P<0.01);21 d与28 d和5