Gender and estrogen supplementation increases severity of experimental choroidal neovascularization

Observational clinical studies suggest that post-menopausal women may be at risk for more severe age-related macular degeneration, and that estrogen loss due to menopause may contribute. We sought to determine the effect of gender and estrogen status on the severity of choroidal neovascularization (CNV) in a mouse model for experimental choroidal neovascularization. Laser-induced CNV was performed in mice with or without estrogen supplementation. At various times, eyes were removed for analysis of severity of CNV lesions or for extraction of choroidal mRNA to evaluate iNOS, TNF-alpha, MMP-9, and ER-alpha expression, which are molecules relevant to angiogenic processes. Also, splenic macrophages were analysed for iNOS to determine the effect of estrogen treatment in vitro. Finally, laser-induced CNV was performed in iNOS -/- mice. Our result showed that aged female mice had significantly larger CNV than age-matched males. Ovariectomy in adult mice did not increase severity, but paradoxically estrogen supplementation after ovariectomy did increase CNV severity. More severe CNV were associated with a significant decrease in choroidal iNOS mRNA. Splenic macrophages from estrogen supplemented mice showed a significant increased in TNF-alpha mRNA expression (eight fold difference compared to the control) but only a mild change in iNOS mRNA levels (2-3 fold difference). In vitro data further showed that nitric oxide production in splenic macrophages at different estrogen levels was not different from controls. Finally, CNV severity was significantly more severe in iNOS -/- mice, compared to iNOS +/+ mice after laser treatment. In conclusion, aged female mice developed more severe CNV than do males. Estrogen replacement seems to increase severity, possibly by suppressing the upregulation of choroidal iNOS and activating macrophages. The putative beneficial or detrimental role of estrogen biology in age-related macular degeneration must be more carefully evaluated and may vary with the stage of age-related macular degeneration (atrophic or neovascular) as well as with the specific target cell type (monocytes vs. endothelial cell or vascular smooth muscle cell).     

Macrophage depletion diminishes lesion size and severity in experimental choroidal neovascularization

PURPOSE: Macrophage recruitment to the choroid has been proposed to contribute to the pathogenesis of choroidal neovascularization (CNV) in AMD. The study was conducted to determine whether treatment with clodronate liposomes (CL(2)MDP-lip), which cause depletion of blood monocytes and lymph node macrophages, diminishes the severity of neovascularization in a mouse model of laser-induced CNV. METHODS: Laser-induced CNV was performed in female 16-month-old C57BL/6 mice. Macrophages were depleted by use of CL(2)MDP-lip intraperitoneally and subcutaneously 72 and 24 hours before and every 2 to 3 days after laser injury. Control mice received injections of either PBS alone or PBS liposomes. Blood monocyte and choroidal macrophage depletion were documented by flow cytometry and choroidal flatmount preparation analysis, respectively. Two weeks after laser injury, mice were injected intravenously with fluoresceinated dextran. The right eyes were removed and prepared for flatmount analysis of CNV surface area (in relative disc areas or DA), vascularity (relative fluorescence), and cellularity (propidium iodide stain). The mice were then perfused with 10% formaldehyde, and the left eyes were removed for histopathology. The means of the various parameters for four CNV lesions per eye were calculated. Fluorescein angiography was also performed. RESULTS: Flow cytometry of circulating monocytes and immunohistochemical analysis of choroidal macrophage density confirmed the effective depletion of blood monocytes and choroidal macrophages respectively in CL(2)MDP-lip-treated mice. Compared with the control, flatmount analysis of macrophage depleted mice demonstrated a significant reduction in size of the CNV area (2.8 +/- 0.5 DA vs. 1.4 +/- 0.1 DA; P < 0.043). The treated group also revealed less vascularity (1.6 +/- 0.1 units vs. 1.1 +/- 0.0 units; P < 0.0092) and cellularity of CNV lesions (3.3 +/- 0.6 DA vs. 1.7 +/- 0.1 DA, P < 0.04). Histopathology revealed that, in the macrophage-depleted group, CNV was smaller in diameter (1270 +/- 73 pixels vs. 770 +/- 82 pixels, P < 0.0006) and thickness (120 +/- 7 pixels vs. 96 +/- 7 pixels, P < 0.019). CONCLUSIONS: Macrophage depletion using CL(2)MDP-lip reduces size, cellularity, and vascularity of CNV. This observation supports the hypothesis that macrophages contribute to the severity of CNV lesions.     

Nicotine promotes contribution of bone marrow-derived cells to experimental choroidal neovascularization in mice

Nicotine can increase size and severity of experimental choroidal neovascularization (CNV); however, the mechanism is uncertain. Recent studies demonstrated that the development of CNV involves the contribution of bone marrow-derived cells (BMCs). This study aims to investigate the effects and the potential mechanism of nicotine on BMCs' contribution to CNV. Green fluorescent protein (GFP) chimeric mice were developed by transplanting bone marrow cells from GFP transgenic mice to C57BL/6J mice. CNV was induced by lasering. Nicotine was administered orally in drinking water. Histopathologic study and choroidal flatmount were performed to measure the CNV severity and BMCs recruitment. BMCs expressing different cell markers in CNV and local expressions of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and vascular cell adhesion molecule-1 (VCAM-1) were detected by immunofluorescence. Nicotine administration resulted in larger diameter and surface area of CNV (P<0.05). Nicotine-exposed mice demonstrated increased area and density of GFP+ cells, increased GFP+ vascular cells area, and decreased ratio of BMCs expressing F4/80 in CNV (P<0.05). Furthermore, the expression of VEGF and bFGF within CNV and VCAM-1 in choroid beneath CNV was up-regulated in nicotine-exposed mice. Our results suggest that nicotine promotes recruitment and incorporation of BMCs into CNV and affects differentiation of BMCs in CNV. These effects may be partly due to indirect actions of nicotine on BMCs via other factors (e.g. VEGF or VCAM-1). It is helpful to understand the mechanism of the effect of nicotine in CNV development.     

Age as an independent risk factor for severity of experimental choroidal neovascularization

PURPOSE: For many vascular diseases, aging appears to be an independent risk factor for severity of vascular complications, and blood vessels of aged individuals often demonstrate exaggerated repair responses to injury. This study was undertaken to determine the influence of aging on the severity of neovascularization in a mouse model of laser-induced choroidal neovascularization (CNV). METHODS: CNV was induced in young (2-month-old) and aged (16-month-old) C57BL/6 mice by making four separate choroidal burns in each eye with a diode red laser (650 nm). At 1, 2, and 4 weeks, the left eyes were removed for histopathology, and the right eyes were removed for flatmount analysis of CNV surface area, vascularity, and cellularity. RESULTS: Aged mice demonstrated a much larger area of CNV than did young mice (3.81 +/- 1.28 vs. 1.36 +/- 0.99 disc areas, P < 0.001) at 2 weeks, when the lesions showed maximum growth. Aged mice also demonstrated higher ratios for vascularity and cellularity of the CNV (1.34 +/- 0.06 vs. 1.03 +/- 0.11, P < 0.0001 and 4.06 +/- 1.19 vs. 1.91 +/- 0.81, P < 0.002 at 2 weeks, respectively). Histopathology revealed that CNV in older eyes was larger, thicker, and more cellular than in young eyes. CONCLUSIONS: In mice, age is associated with more severe CNV, defined as larger surface area, greater vascularity, and greater cellularity. Age-related systemic susceptibility factors, independent of local changes in the retina, may contribute to the greater severity of CNV in older than in younger individuals.     

实验性脉络膜新生血管的定量评价

目的 评价氪激光诱导下大鼠脉络膜新生血管(choroidal neovascularization,CNV)面积计算的可行性.方法 采用氪激光击破大鼠右眼 Bruch 膜的方法诱导24只大鼠产生实验性 CNV,另一眼作正常对照眼.眼底彩照及眼底血管荧光造影检查(fundus fluorescein angiography,FFA)分别于光凝后1周、2周、3周、4周时观察大鼠眼底CNV渗漏情况,脉络膜铺片技术测量CNV面积.结果 氪激光大鼠CNV模型成模率3周、4周时稳定(75.00%、78.75%).从FFA、脉络膜血管铺片技术可见大鼠CNV面积随造模后时间延长呈明显递增生长(P＜0.05),3周、4周时差异不明显,病理切片亦可见CNV中新生血管数量的增多.结论 FFA检查、脉络膜血管铺片技术、病理切片均可作为评价CNV生长的指标,其中脉络膜血管铺片技术是CNV定量评价的可靠方法.     

Multimodal imaging of experimental choroidal neovascularization

AIM: To compare choroidal neovascularization (CNV) lesion measurements obtained by in vivo imaging modalities, with whole mount histological preparations stained with isolectin GS-IB4, using a murine laser-induced CNV model. METHODS: B6N.Cg-Tg(Csf1r-EGFP)1Hume/J heterozygous adult mice were subjected to laser-induced CNV and were monitored by fluorescein angiography (FA), multicolor (MC) fundus imaging and optical coherence tomography angiography (OCTA) at day 14 after CNV induction. Choroidal-retinal pigment epithelium (RPE) whole mounts were prepared at the end of the experiment and were stained with isolectin GS-IB4. CNV areas were measured in all different imaging modalities at day 14 after CNV from three independent raters and were compared to choroidal-RPE whole mounts. Intraclass correlation coefficient (ICC) type 2 (2-way random model) and its 95% confidence intervals (CI) were calculated to measure the correlation between different raters'' measurements. Spearman''s rank correlation coefficient (Spearman''s r) was calculated for the comparison between FA, MC and OCTA data and histology data. RESULTS: FA (early and late) and MC correlates well with the CNV measurements ex vivo with FA having slightly better correlation than MC (FA early Spearman''s r=0.7642, FA late Spearman''s r=0.7097, and MC Spearman''s r=0.7418), while the interobserver reliability was good for both techniques (FA early ICC=0.976, FA late ICC=0.964, and MC ICC=0.846). In contrast, OCTA showed a poor correlation with ex vivo measurements (Spearman''s r=0.05716) and high variability between different raters (ICC=0.603). CONCLUSION: This study suggests that FA and MC imaging could be used for the evaluation of CNV areas in vivo while caution must be taken and comparison studies should be performed when OCTA is employed as a CNV monitoring tool in small rodents.     

Macrophage depletion inhibits experimental choroidal neovascularization

OBJECTIVE: To investigate the role of macrophages in the development of laser-induced choroidal neovascularization (CNV) by selective depletion with liposomal clodronate (Cl(2)MDP-LIP). METHODS: Laser photocoagulation was used to induce CNV in wild-type C57BL/6J mice. Animals were treated with intravenous (IV) and/or subconjunctival (SC) Cl(2)MDP-LIP or PBS-LIP at the following time points: 2 days before, immediately after, 2 days before and immediately after, or 2 days after laser injury. CNV responses were compared on the basis of en masse volumetric measurements and fluorescein angiography after laser photocoagulation. Macrophages were identified by immunostaining for F4/80, and vascular endothelial growth factor (VEGF) expression was quantified by ELISA. RESULTS: Macrophages invaded the site of laser injury within 1 day of photocoagulation and peaked at 3 days. IV Cl(2)MDP-LIP significantly decreased the volume of CNV and angiographic leakage when administered 2 days before and/or immediately after laser injury, but not when administered 2 days after injury. SC Cl(2)MDP-LIP significantly decreased lesion volume when coadministered with IV PBS-LIP but not IV Cl(2)MDP-LIP. IV Cl(2)MDP-LIP was significantly more beneficial when administered 2 days before laser injury than immediately after, but combining SC Cl(2)MDP-LIP with IV treatment eliminated this difference. Reduction in CNV volume correlated with VEGF protein levels and number of infiltrating macrophages. CONCLUSIONS: Generalized macrophage depletion reduced the size and leakage of laser-induced CNV and was associated with decreased macrophage infiltration and VEGF protein. These findings define the role of the macrophage as a critical component in initiating the laser-induced CNV response.     

Electron microscopic features of experimental choroidal neovascularization

We produced choroidal neovascularization in the rhesus monkey by diminishing the blood supply to the inner retina and producing defects in Bruch's membrane by photocoagulation. The neovascular fronds which developed either infiltrated the subretinal space or proliferated through necrotic and gliotic retina into the vitreous cavity. Sequential electron microscopic sections of neovascular fronds in the subretinal space demonstrated that the advancing capillary sprouts were composed of primitive endothelial tubes surrounded by pericytes and enmeshed in a loose basement-membrane-like substance. More mature capillaris and displayed endothelial fenestrations and endothelial-pericyte membranous contacts. Large neovascular fronds developed major feeding vessels that closely resembled normal small choroidal arteries and veins. Retinal pigment epithelial cells in various guises were in constant association with proliferating neovascular networks.     

康柏西普对实验性脉络膜新生血管的作用机制研究

目的　探究康柏西普对实验性脉络膜新生血管（choroidal neovascularization，CNV）的作用机制。方法　选取40只7周龄的雄性BN大鼠，采用多波长氪激光对豚鼠左眼行视网膜光凝，制作CNV大鼠模型，并随机分为4组，空白对照组、模型组、低剂量康柏西普组和高剂量康柏西普组；于造模后7 d、14 d注射康柏西普，并在造模后21 d进行右眼眼底彩照、眼底荧光素血管造影（fundus fluorescein angiography，FFA）检查，检测CNV 发生率及渗漏面积，使用FITC灌注脉络膜铺片测量CNV面积，使用HE染色观察大鼠视网膜结构，使用Western blot检测大鼠视网膜中血管内皮生长因子（vascular endothelial growth factor，VEGF）、缺氧诱导因子-1α（hypoxia-inducible factor-1α，HIF-1α）、丝氨酸/苏氨酸激酶 （serine/threonine kinase，AKT）表达情况。结果　除吲哚菁绿血管造影荧光点数、CNV发生率外，相比空白对照组，模型组大鼠CNV渗透面积，荧光素渗漏面积，脉络膜结构损伤程度，视网膜中 HIF-1α、AKT和VEGF蛋白的表达均显著升高，差异均有统计学意义（均为P<0.05）；相比模型组，康柏西普组大鼠上述各指标显著降低，高剂量康柏西普组上述各指标显著低于低剂量康柏西普组，差异均有统计学意义（均为P<0.05）。结论　康柏西普可以抑制脉络膜视网膜中 HIF-1α、AKT和VEGF蛋白的表达，从而抑制由氪激光光凝眼底而产生的实验性CNV生长。     

A novel imaging technique for experimental choroidal neovascularization

PURPOSE: Choroidal neovascularization (CNV) is the end point of several ocular diseases that lead to blindness. The authors developed an imaging technique for visualizing and quantifying morphologic changes associated with experimental laser-induced CNV. METHODS: CNV was induced using laser energy to disrupt Bruch's membrane. Rats were euthanatized immediately after laser injury and at 1, 2, 3, 4, 7, 14, and 60 days. Nonlasered eyes were used as the control. Eyes were enucleated and fixed, and the posterior eye cups were fluorescently labeled with markers for nuclei (DAPI; 4',6'-diamino-2-phenylindole), endothelial cells (isolectin IB4), microglia (CD11b), and filamentous actin (phalloidin). FITC-dextran perfusion was compared with our technique. A confocal microscope was used to evaluate flatmounted specimens. Computer software generated three-dimensional reconstructions for qualitative and quantitative analysis of confocal image stacks. RESULTS: In nonlasered areas, RPE cells were visualized as a uniform hexagonal array. Immediately after laser exposure, a circular area devoid of fluorescent labeling was observed, indicating disruption of the choroid-Bruch's membrane-RPE complex. One day after laser exposure, cellular debris and fragmented nuclei were present, and an autofluorescent ring was visible at the site of Bruch's membrane disruption. The ring correlated with bubble formation and CNV induction. Three days after laser injury, phalloidin-labeled RPE cells and isolectin-labeled endothelial cells increased significantly, reflecting cell proliferation and migration. By day 4, isolectin-positive cells forming vascular tubes were visualized. The volume of CNV vessels increased exponentially during the next 3 days. By 7 days, a well-defined isolectin-labeled CNV network was present, and its volume was preserved for several weeks. CNV volumes calculated on the basis of FITC-dextran perfusion were significantly lower than volumes obtained using lectin-labeled samples. CONCLUSIONS: A novel imaging technique was developed that allows a three-dimensional reconstruction and measurement of laser-induced CNV lesions in rat choroid/RPE flatmounts. This technique provides excellent morphologic detail and facilitates the study of critical early events in CNV, including the rupture of Bruch's membrane and the formation of endothelial clusters before vessel formation. CNV complexes are labeled at an earlier stage and more reproducibly than with FITC-dextran perfusion, providing a more accurate preclinical evaluation of antiangiogenic molecules.     

沙利度胺治疗脉络膜新生血管的实验研究

目的探讨沙利度胺（thalidomide）对脉络膜新生血管（CNV）的抑制作用及毒副作用。方法健康C57BL／6J小鼠采用氪红激光光凝建立CNV模型。随机分组：A组为对照组;B组腹腔注射沙利度胺,浓度为10mg／kg;C组腹腔注射沙利度胺浓度为50mg／kg。连续应用10d。记录实验前后小鼠体重变化。从防御反射、捕捉难易度、进食量、皮毛颜色及精神状态等5个方面来评估小鼠行为学改变。病理组织学检查测量CNV组织厚度。结果小鼠体重变化有明显差异,C组小鼠体重增加明显小于A组和B组（P〈0．01）。A组和B组小鼠行为学基本没有改变。C组小鼠行为学改变明显。3组小鼠CNV组织中央厚度有明显差异;A组小鼠CNV组织中央厚度高于B、C两组（P〈0．01）。结论沙利度胺能够抑制实验性CNV;在常规用药剂量下,小鼠能较好的耐受沙利度胺,当药物浓度过大时,其抑制CNV的作用没有增加,但副作用明显严重。     

Photodynamic therapy of experimental choroidal neovascularization in the mouse

PURPOSE: To evaluate the qualitative and quantitative effects of verteporfin photodynamic therapy (PDT) on laser-induced choroidal neovascularization (CNV) in the mouse. METHODS: PDT was applied to the normal mouse fundus using light doses of 32, 64, and 83 s, and histological analysis of the treated areas was performed. CNV was induced using krypton laser photocoagulation of the fundus, and the CNV lesions were subsequently treated with PDT using light doses of 32, 64, and 83 s. Enucleated eyes were analyzed with light and transmission electron microscopies, and measurements of CNV size were done on histologic sections and on isolectin B4-stained choroidal flat mounts. RESULTS: PDT induced a light dose-dependent damage to the surrounding neural retina in normal eyes. At a light dose of 32 s, minimal damage was detected in the neural retina, whereas higher light doses caused distortion and disruption of the outer and inner nuclear layers and of the retinal pigment epithelium. When PDT was applied over laser-induced CNV lesions, the relative height of the lesions was significantly reduced (p < 0.05) using all light doses. Transmission electron microscopy 1 day after PDT treatment revealed occlusion of many of the CNV vessels. One week after PDT treatment, the CNV lesions contained patent vessels irrespective of light dose applied. Accordingly, PDT treatment inhibited (p < 0.05) but did not halt CNV lesion growth. CONCLUSIONS: PDT treatment of laser-induced CNV may create an acute occlusion of neovessels and an inhibition of CNV lesion growth without apparent injury to the surrounding neural retina. However, PDT-treated areas will remain vascularized with continued growth of the CNV lesion, which in turn may explain the often limited effect of PDT in patients with neovascular age-related macular degeneration. Elevating the PDT light dose will not increase the treatment effect substantially but may lead to increased collateral injury.     

Expression of pigment epithelium-derived factor in experimental choroidal neovascularization

PURPOSE: To investigate the expression of pigment epithelium-derived factor (PEDF) in the rat laser-injury model of choroidal neovascularization (CNV). METHODS: Retinas were immunostained for PEDF at different times (1, 2, and 3 weeks) after laser injury. Levels of PEDF protein in the vitreous at 1, 3, 7, 14, and 28 days after laser injury were also assayed by Western blot. RESULTS: Protein levels of PEDF in the vitreous were increased during the first 7 days after CNV induction. Immunostaining for PEDF was observed throughout normal nonlasered control retinas, sham-lasered retinas, and areas remote to laser lesions, which were generally more intense in the outer nuclear layer (ONL) and less intense in the internal nuclear layer (INL). Decreased expression of PEDF was observed in flanking areas adjacent to the injury site and was confined mainly to the ONL. In the injury sites, immunostaining within the ONL was either absent or decreased for up to 3 weeks after laser injury (the duration of the study). Preadsorption of the anti-PEDF antibody with the immunizing peptide blocked specific labeling in the retina. CONCLUSIONS: These results demonstrate an inverse correlation of expression of PEDF and formation of CNV in the experimental model and suggest that decreased expression of PEDF plays a permissive role in the formation of CNV. PEDF analogues may be a reasonable treatment strategy for CNV.     

塞来昔布对实验性脉络膜新生血管的抑制作用

目的　观察选择性环氧化酶-2 (COX-2)抑制剂塞来昔布（celecoxib）对实验性脉络膜新生血管（CNV）的抑制作用。方法　鼠龄8~10周的健康雄性棕色挪威（BN）大鼠30只,随机分为空白对照组、实验对照组和塞来昔布治疗组,每组10只。塞来昔布治疗组采用灌胃法给药,剂量50 mg/kg,2次/d。给药后7 d,采用氪激光建立大鼠CNV模型,分别于激光光凝后3、7、14、21、30 d对实验对照组和塞来昔布治疗组所有大鼠行荧光素眼底血管造影(FFA)检查。激光光凝后21 d,每组随机处死5只大鼠,摘除眼球,制作空白对照组球后段组织切片、实验对照组和治疗组CNV膜切片。常规苏木精-伊红（HE）染色,计算实验对照组和塞来昔布治疗组的CNV膜相对厚度;采用免疫组织化学方法检测COX-2、血管内皮生长因子（VEGF）及基质金属蛋白酶-2（MMP-2)的表达。结果　激光光凝后21 d,塞来昔布治疗组 CNV发生率明显低于实验对照组（χ2=7.106 8,P=0.007 7）,CNV相对厚度较实验对照组明显减少（t=16.760 0,P=0.000 0）,COX-2、VEGF和MMP-2在CNV膜上的阳性表达均明显低于实验对照组（t=5.710 0,5.840 0,8.020 0;P=0.000 0）;空白对照组大鼠COX-2、VEGF和MMP-2在视网膜和脉络膜中的表达非常弱。结论　预防性服用塞来昔布能抑制激光诱导CNV的发生;通过抑制COX-2可减少CNV中VEGF和MMP-2的表达。     

Bone marrow-derived progenitor cells contribute to experimental choroidal neovascularization

PURPOSE: The pathogenesis of choroidal neovascularization (CNV) is postulated to be driven by angiogenesis, a process in which the cellular components of the new vessel complex are derived from cells resident within an adjacent preexisting capillary. Recently, an alternative paradigm, termed postnatal vasculogenesis, has been shown to contribute to some forms of neovascularization. In vasculogenesis, the cellular components of the new vessel complex are derived from circulating vascular progenitors from bone marrow. In the current study, transplantation of green fluorescent protein (GFP)-labeled bone marrow and laser-induced CNV were combined to examine the contribution of vasculogenesis to the formation of CNV. METHODS: Ten adult C57BL/6 female mice were used as recipients for bone marrow transplantation. Bone marrow was obtained from three C57BL/6 female mice transgenic for the beta-actin promoter GFP. One month after bone marrow transplantation, CNV was induced in recipient mice by making four separate burns in the choroid of each eye with a red diode laser. Four weeks after CNV was induced, eyes of recipient mice were processed for immunohistochemistry to detect GFP and markers for vascular smooth muscle cells (alpha-smooth muscle actin, desmin, and NG2 chondroitin sulfate proteoglycan), endothelial cells (CD31, BS-1 lectin), or macrophages (F4/80). RESULTS: GFP-labeled cells represented 17% of the total cell population in the lesion. Many of the GFP-labeled cells were immunoreactive for alpha-smooth muscle actin (39%), desmin, NG2, CD31 (41%), BS-1 lectin, or F4/80. GFP-labeled cells were morphologically indistinguishable from cells normally present in CNV lesions. CONCLUSIONS: This study is the first to demonstrate that bone marrow-derived progenitor cells are a source of endothelial and smooth musclelike cells in CNV.     

荧光抗体标记法在小鼠脉络膜新生血管中的应用

背景脉络膜新生血管（CNV）是导致多种眼底疾病视力损害的主要原因,准确建立CNV模型对于其实验和临床研究具有重要的意义,但目前尚无一种可重复且可靠的评估CNV模型及其有效治疗的方法。目的探讨荧光抗体标记法在定性和定量评价氪激光诱导的小鼠CNV中的应用价值。方法选取15只雄性SPF级C57BL／6J小鼠,用氪激光（波长为647．1am）视网膜光凝的方式建立CNV模型。分别于光凝后5rain,4、7、14及28d随机选取3只模型小鼠行眼底照相和荧光素眼底血管造影（FFA）检查。摘除眼球行脉络膜铺片,用荧光抗体（DAPI、isolectin-B4及phalloidin）分别标记光凝区域的细胞核、内皮细胞和肌动蛋白。用Imageproplus6．0软件测量CNV面积。结果FFA和脉络膜铺片检查结果显示激光光凝后5min及4d无CNV形成,光凝后7d开始出现CNV。光凝后7、14、28d有荧光素渗漏的光凝斑的百分率分别为76．47％（26／34）、81．81％（18／22）和50．00％（5／10）。脉络膜铺片后荧光显微镜检测结果显示,在正常的未光凝区域,视网膜色素上皮（RPE）细胞呈均匀一致的六边形排列;光凝后5min,在光凝部位可检测到一个环形荧光素缺损区,表明脉络膜-Bruch膜-RPE复合体已被破坏;光凝后4d出现一些细胞碎片以及核碎片,Bruch膜破损处可见自发荧光环。光凝后7d时,激光损伤区出现界限清楚的CNV网,并持续到28d。7、14及28d时根据脉络膜铺片所测得的CNV面积分别为（7．99±0．42）×10^3、（16．89±8．77）×10^3、（14．37±4．02）×10^3μm^2,差异有统计学意义（F=17．340,P=0．000）。光凝后14d和28d脉络膜铺片上CNV面积相差不大,但与7d时相比面积均明显增加（q=16．46、q=15．54,P〈0．01）。结论荧光抗体标记法不仅能很好地显示氪激光诱导的小鼠实验性CNV及其形态,而且能测定CNV的面积,为抗新生血管药物应用的疗效研究提供依据。     

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。