大鼠角膜碱烧伤后ILK和VEGF的表达与角膜新生血管的相关性研究

目的:研究大鼠角膜碱烧伤后整合素连接激酶(ILK)、血管内皮生长因子(VEGF)的表达及其与角膜新生血管(CNV)的相关性.方法:通过碱烧伤Sprague-Dawley(SD)大鼠角膜制备角膜新生血管动物模型,采用形态学方法观察碱烧伤后新生血管的生成,免疫组织化学方法检测ILK及VEGF在碱烧伤后不同时间点的表达情况.结果:ILK及VEGF在正常大鼠角膜上皮中仅有微弱表达,而在碱烧伤后各时间点的角膜上皮以及血管内皮中均有明显表达(P<0.01).碱烧伤后3~5d,可见二者阳性表达,且迅速增加;7~10d,二者表达达到高峰;14d以后二者表达逐渐减弱,与形态学观察CNV生长过程一致.即碱烧伤后3~5d新生血管生长迅速,7~10d生长达到高峰,14d以后血管开始逐渐减少退化.ILK及VEGF表达的变化均与CNV的变化呈正相关(ILK与CNV面积相关系数r=0.900,P<0.01;VEGF与CNV面积相关系数r=0.878,P<0.01),且二者之间也存在正相关性(r=0.926,P<0.01).结论:大鼠角膜碱烧伤后ILK及VEGF均有明显表达,二者作为重要的调控子共同参与了CNV的形成过程.     

HGF和VEGF在大鼠角膜碱烧伤后新生血管形成中的表达

目的 探讨大鼠角膜碱烧伤后肝细胞生长因子(hepatocyte growth factor,HGF)、血管内皮生长因子(vascular endothelial growth factor,VEGF)的表达与角膜新生血管 (corneal neovascularization,CNV)的关系.方法 40只Wistar大鼠随机分为对照组和实验组,实验组制备碱烧伤CNV模型,观察碱烧伤后第1天、第4天、第7天、第14天CNV生长情况,并采用免疫组织化学法检测各时间点角膜HGF及VEGF蛋白表达.结果 第4天、第7天、第14天实验组CNV面积分别为:(13.10±0.78)mm2、(27.84±0.56)mm2、(36.45±0.75)mm2.免疫组织化学显示HGF在正常角膜内皮细胞少量表达,VEGF不表达;角膜碱烧伤后HGF 及VEGF的蛋白表达迅速升高,第4天达到高峰,第7天显著下降.结论 HGF及VEGF参与了CNV的形成过程,HGF与VEGF 2者表达失衡可能与CNV形成及发展有关.     

血管内皮生长因子与角膜碱烧伤后血管新生

目的　探讨血管内皮生长因子(VEGF)在大鼠角膜碱烧伤后角膜新生血管形成中的作用。方法　利用氢氧化钠烧灼大鼠角膜表面,建立大鼠角膜新生血管(CNV)模型,每日裂隙灯下观察角膜新生血管的发展,并分别于烧伤后1、4、7、14、2 1d处死大鼠,摘除角膜作病理切片,多形核白细胞(PMN)计数;免疫组化法检测VEGF的表达;图像分析系统测定该因子的蛋白表达。结果　光镜下显示正常组PMN记数为0 . 5 0 0±0 . 62 9,烧伤后1d角膜缘处的PMN开始增多,7d时增加最明显,此后逐渐减少;免疫组化显示:VEGF在CNV中阳性表达逐渐增加,于7d组表达最明显,2 1d后几乎无表达;图像分析与免疫组化结果一致。结论　碱烧伤后CNV形成中,VEGF的表达增加,并与角膜的炎性反应程度平行,PMN浸润可能是CNV形成的关键因素。     

环氧合酶-2及其抑制剂对角膜新生血管作用的研究

目的 观察大鼠角膜新生血管（CNV）形成过程中环氧合酶-2（COX-2）的表达,探讨COX-2抑制剂Celecoxib对CNV的作用.方法 采用免疫组织化学方法、RT-PCR法检测碱烧伤后COX-2和VEGF蛋白、mRNA在角膜中的分布,比较实验组和对照组COX-2与VEGF蛋白和mRNA的表达量,计算二者的相关性.结果 碱烧伤2 d,CNV芽形成,4 d出现成熟的新生血管腔.活化的COX-2、VEGF蛋白和mRNA的表达在碱烧伤24 h开始增加,4 d达峰,7 d开始回落,14 d仍有表达.COX-2主要表达于大鼠角膜损伤上皮及修复的上皮层、基质层中浸润的炎性细胞和新生血管内皮细胞,VEGF与COX-2的表达部位一致.实验Ⅱ组和Ⅲ组COX-2和VEGF蛋白、mRNA表达量与对照组的差异有统计学意义（P＜0.05）,实验Ⅰ组与对照组的差异无统计学意义（P＞0.05）.结论 COX-2在炎性CNV形成过程中表达上调,通过调控VEGF的表达而起重要作用.Celecoxib抑制COX-2的表达,抑制CNV形成.     

血管内皮生长因子反义核苷酸抑制大鼠角膜新生血管的实验研究

目的探讨重组腺相关病毒介导的血管内皮生长因子反义核苷酸(rAAV aVEGF165)抑制大鼠角膜新生血管(CNV)发生与发展的作用。方法三质粒共转染法构建rAAV aVEGF165和重组腺相关病毒介导的β半乳糖苷酶的结构基因(rAAV Lacz)。48只SD大鼠用抽签法随机分成实验组和对照组,每组24只,碱烧伤方法诱导CNV生成。实验组结膜囊注射rAAV aVEGF165(1010pfu/ml),对照组结膜囊注射rAAV Lacz(1010pfu/ml);5溴4氯3吲哚βD半乳糖苷(X gal)组织化学染色,检测Lacz基因在结膜囊中的表达情况;碱烧伤后1、2、4、7、14及30d,形态学分析评价角膜新生血管的生长情况,免疫组织化学检测角膜组织中VEGF的表达。结果对照组rAAV Lacz结膜囊注射2d后,检测Lacz基因在结膜组织中的表达效率为21.36%±1.07%;30d后Lacz基因在结膜下组织中的表达效率为28.02%±1.16%。碱烧伤后结膜囊注射rAAV aVEGF165,实验组CNV面积明显减少,新生血管密度降低,VEGF在角膜组织中的表达明显降低,差异有统计学意义(F=1639.22,F=2187.16,F=719.17,P<0.01)。结论rAAV aVEGF165能显著抑制碱烧伤后CNV的形成,其机制与降低角膜组织中VEGF的表达有关,重组腺相关病毒是眼反义基因治疗的有效载体。     

血管内皮生长因子shRNA表达质粒抑制鼠角膜新生血管与血管内皮细胞中血管内皮生长因子的表达

目的 探讨RNA干扰对大鼠碱烧伤后角膜新生血管(CNV)与血管内皮细胞(EC)中血管内皮生长因子(VEGF)表达的影响及作用机制.方法 实验研究.采用DNA重组技术设计合成针对VEGF mRNA的3条shRNA寡核苷酸片段,构建真核表达质粒VEGF shRNA1、2、3,然后将质粒通过脂质体介导分别转染EC,逆转录聚合酶链反应和Western blot免疫印迹法分别检测EC中VEGF mRNA和蛋白的表达及干扰效率,并筛选出干扰效率最高的质粒(VEGF shRNA3质粒)进行体内实验.将20只SD大鼠按完全随机设计方法分为两组,分别为实验组10只和对照组10只,建立大鼠碱烧伤后CNV模型.实验组于结膜下注射VEGF shRNA3质粒后,显微镜下观察CNV生长情况,7 d后利用逆转录聚合酶链反应(RT-PCR)与Western blot法分别检测实验组和对照组角膜组织VEGF mRNA和蛋白的表达.多组间差异显著性检验用单因素方差分析,两组CNV面积比较采用重复测量的方差分析.结果 经酶切及测序证实重组质粒构建成功.VEGF shRNA1、2、3质粒均可下调VEGF mRNA和蛋白的表达,其中VEGF shRNA3质粒的抑制作用较强,VEGF mRNA和蛋白的抑制率分别为68.92%和66.22%.体内实验中碱烧伤后3、5、7 d,实验组CNV长度较对照组明显降低,差异有统计学意义(F=355.744,P=0.000);实验组CNV面积较对照组明显降低,差异有统计学意义(F=402.700,P=0.000);实验组VEGF mRNA和蛋白在角膜组织中的表达较对照组明显降低,抑制率分别为41.84%和41.86%.结论 构建的VEGF shRNA质粒能右效抑制EC中VEGF mRNA和蛋白的表达.结膜下注射VEGF shRNA3质粒能显著抑制碱烧伤后CNV的形成与VEGF的表达.     

HIF在兔角膜碱烧伤后CNV生成中的作用研究

目的研究缺氧诱导因子(hypoxia inducible factor,HIF)以及诱导性一氧化氮合成酶(inducible nitric oxide synthase,iNOS)和血管内皮生长因子(vascular endothelial growth factor,VEGF)在角膜碱烧伤后角膜新生血管(corneal neovascularization,CNV)形成中的作用及机制。方法 建立兔CNV动物模型,将其随机分为对照组和3个实验组,对照组结膜下注射生理盐水,实验组注射不同剂量的三氧化二砷。观察兔CNV的生长情况,并记录CNV的生长面积。用免疫组织化学方法检测兔角膜HIF、iNOS以及VEGF的表达。结果 对照组6 d、12 d、15 d、21 d、28 d CNV的面积分别为:(53.86±20.60)mm2、(87.21±25.80)mm2、(128.31±40.10)mm2、(114.42±29.40)mm2、(78.15±35.13)mm2。各实验组CNV面积均小于对照组,差异均有统计学意义(均为P<0.05)。免疫组织化学方法检测角膜HIF-1α、iNOS及VEGF蛋白的表达:VEGF表达集中在角膜上皮下基质,存在于血管内皮细胞、炎性细胞胞浆内,呈深黄色。在7 d有较高表达,14 d达到高峰,28 d时明显降低,且对照组明显高于实验组,各实验组的表达随三氧化二砷剂量的增加而减少。蛋白的表达与CNV面积呈正相关。结论 角膜碱烧伤后CNV的形成可能与HIF-1α有关。三氧化二砷通过抑制HIF-1α和iNOS、VEGF表达而抑制兔CNV的形成。     

大鼠角膜碱烧伤行培养角膜上皮移植后VEGF的表达

目的 研究角膜上皮培养移植后角膜新生血管(CNV)形成和血管内皮生长因子(VEGF)的变化特点.方法 对角膜碱烧伤CNV大鼠行培养角膜上皮移植,观察术后CNV程度,RT-PCR和免疫组织化学法检测术后24、48、72、168 h角膜组织VEGF的表达.结果 实验组角膜上皮移植后14 d CNV接近瞳孔区,之后逐渐减退.移植后24 h角膜VEGF mRNA的相对含量为1 20±0.09;48 h为1 91±0.03;72 h为2.34±0.11;168 h为1.83 ±0.14.角膜上皮和基质均表达VEGF蛋白,以上皮层表达为主,并随时间推移表达量增加.结论 培养角膜上皮移植后24 h角膜可表达VEGF,72 h表达量最高.VEGF表达与培养角膜上皮移植后CNV的发生密切相关.     

反应停对大鼠碱烧伤诱导角膜新生血管的影响

目的:研究反应停(thalidomide)对碱烧伤诱导角膜新生血管(corneal neovascularization,CNV)的影响。方法:建立大鼠角膜碱烧伤诱导CNV模型,SD大鼠36只随机分成角膜新生血管对照组(A组)、反应停灌胃组(B组)和反应停球结膜下注射组(C组)。采用裂隙灯照相、免疫组化和RT-PCR等方法,检测碱烧伤后各时间点不同处理方法大鼠CNV的生长情况及VEGF的表达情况。结果:B组和C组的角膜新生血管面积和VEGF的表达均显著少于A组(P均(0.05);C组的角膜新生血管面积和VEGF的表达少于B组(P均<0.05)。结论:反应停可有效抑制大鼠角膜碱烧伤诱发CNV的生长,降低角膜新生血管VEGF的表达。球结膜下注射较全身应用更有效。     

血管内皮生长因子及其受体在大鼠碱烧伤后角膜新生血管中的表达

目的:探讨血管内皮生长因子(VEGF)及其受体Flk-1在大鼠角膜碱烧伤后新生血管中的表达。方法:应用1mol/LNaOH制作大鼠碱烧伤新生血管模型,随机分为3组,分别于1,4,7及14d处死大鼠取出角膜,免疫组织化学方法和RT-PCR方法检测大鼠角膜中的VEGF及其受体Flk-1的表达。结果:正常大鼠角膜中VEGF及Flk-1受体弱表达或不表达。二者均在角膜上皮层,基质层、内皮层及新生血管内皮细胞表达;大鼠角膜碱烧伤后各时间点VEGFmRNA和Flk-1mRNA相对表达量具有相关性。结论:大鼠角膜碱烧伤后,VEGF及其受体Flk-1结合诱导内皮细胞分化及角膜新生血管形成。     

Changes in Bruch's membrane in experimental hypercholesteremia in rats

PURPOSE: We investigated the effect of high cholesterol diet for the aging changes in Bruch's membrane of rats. METHODS: After feeding a 4% cholesterol diet for 15 weeks to three young rats 3 months old and four aged rats 23 months old, we observed the morphological changes of Bruch's membrane by electron microscopy, and made a comparison with rats fed an ordinary diet. RESULTS: In one young rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris formed multiple folds separated from the plasma membrane of the endothelium and showed lamellar thickening and crack in some areas. The elastic fiber layer in Bruch's membrane disappeared partly and some new microfibrils appeared. In one aged rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris showed more lamellar thickening with lumps in some parts. Compared with rats fed an ordinary diet, rats fed a high-cholesterol diet showed thickening of the basement membrane and the changes were more severe. CONCLUSIONS: Our data indicated that high-cholesterol diet might promote age-related changes of Bruch's membrane.     

Advances in imaging in oculoplastics

Color Doppler imaging, computed tomography (CT) and magnetic resonance (MR) imaging are the most precious imaging tools for the clinician in the field of oculoplastics. Orbital and facial vasculature, with its dynamic changes and flow velocities seen in orbital varices, carotid-cavernous fistulas, and dural cavernous arteriovenous malformations, is best detected by Color Doppler imaging. Computed tomography remains the dominant imaging modality in the evaluation of orbital trauma. Helical CT axial scanning with multiplanar reconstruction and three-dimensional CT imaging are most helpful in assessing iatrogenic, traumatogenic, and teratogenic orbital abnormalities. Despite its poor histologic specificity, MR imaging provides superior soft tissue contrast, and contrast-enhanced MR imaging has an established role regarding soft tissue tumor infiltration. The greatest value of MR studies in the evaluation of orbital and palpebral tumors is that it has the capacity to show the precise relation between lesions and adjacent structures before the clinician contemplates a surgical approach. Finally, contrast-enhanced MR imaging proved to be a valuable vascularization indicator based upon the extent of relative enhancement within porous orbital implant in anophthalmic socket.     

Follow-up studies in pattern VECP in demyelinating diseases in children

Spectral sensitivity functions and the transient decrease of sensitivity to short wavelengths after the offset of yellow light (transient tritanopia) were measured by increment threshold techniques in patients suffering from hereditary macular degenerations. Color vision defects were determined by arrangement tests and the anomaloscope. Central areolar choroidal dystrophy was found to produce a mild protan defect and to reduce foveal spectral sensitivity throughout the visible spectrum by a factor of 100; it also abolishes transient tritanopia. Electroretinogram (ERG) was normal, electrooculogram (EOG) subnormal. Stargardt's disease, despite numerous fluorescent macular spots, does not abolish transient tritanopia nor does it reduce spectral sensitivity, although scotopic matches were performed on the Nagel anomaloscope. Only in severe, advanced cases was transient tritanopia reduced and spectral sensitivity found to follow the absorption spectrum of rods. Routine ERGs and EOGs were normal. Vitelliform macular degeneration, despite the ophthalmoscopically pronounced dystrophic macula, produced only very small changes in spectral sensitivity and transient tritanopia, although a widened matching range on the Nagel anomaloscope and electrophysiological abnormalities were found. Apparently damage of the retinal circuit which connects long and short wavelength-sensitive cones, caused by hereditary conditions, is different from that caused by retinotoxic drugs.     

Refractive error in children in a rural population in India

PURPOSE: To assess the prevalence of refractive error and related visual impairment in school-aged children in the rural population of the Mahabubnagar district in the southern Indian state of Andhra Pradesh. METHODS: Random selection of village-based clusters was used to identify a sample of children 7 to 15 years of age. From April 2000 through February 2001, children in the 25 selected clusters were enumerated in a door-to-door survey and examined at a rural eye center in the district. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent refractive error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in seven clusters. RESULTS: A total of 4414 children from 4876 households was enumerated, and 4074 (92.3%) were examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 2.7%, 2.6%, and 0.78%, respectively. Refractive error was the cause in 61% of eyes with vision impairment, amblyopia in 12%, other causes in 15%, and unexplained causes in the remaining 13%. A gradual shift toward less-positive values of refractive error occurred with increasing age in both boys and girls. Myopia in one or both eyes was present in 4.1% of the children. Myopia risk was associated with female gender and having a father with a higher level of schooling. Higher risk of myopia in children of older age was of borderline statistical significance (P = 0.069). Hyperopia in at least one eye was present in 0.8% of children, with no significant predictors. CONCLUSIONS: Refractive error was the main cause of visual impairment in children aged between 7 and 15 years in rural India. There was a benefit of spectacles in 70% of those who had visual acuity of 20/40 or worse in the better eye at baseline examination. Because visual impairment can have a significant impact on a child's life in terms of education and development, it is important that effective strategies be developed to eliminate this easily treated cause of visual impairment.     

Vitrectomy in traumatic cataracts and in the complications of surgery in congenital cataract in children

Vitrectomies were carried out in 35 children with traumatic cataracts and complications of surgery for cataracts, caused by injury to the posterior lenticular capsule and incorporation of its fragments to the vitreous. Complete removal of lenticular rudiments rapidly eliminated phacogenic iridocyclitis and improved visual acuity. Improvement of visual functions was attained in 66.6% cases; in 33.4% cases visual acuity did not change. Hemorrhages to the vitreous cavity occurred in 4 cases with pronounced iridocyclitis; therefore, a corneal approach is preferable for cases with pronounced iridocyclitis.     

Refractive error in children in an urban population in New Delhi

PURPOSE: To assess the prevalence of refractive error and related visual impairment in school-aged children in an urban population in New Delhi, India. METHODS: Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age. From December 2000 through March 2001, children in 22 selected clusters were enumerated through a door-to-door survey and examined at a local facility. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent refractive error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in four of the clusters. RESULTS: A total of 7008 children from 3426 households were enumerated, and 6447 (92.0%) examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 6.4%, 4.9%, and 0.81%, respectively. Refractive error was the cause in 81.7% of eyes with vision impairment, amblyopia in 4.4%, retinal disorders in 4.7%, other causes in 3.3%, and unexplained causes in the remaining 5.9%. There was an age-related shift in refractive error from hyperopia in young children (15.6% in 5-year-olds) toward myopia in older children (10.8% in 15-year-olds). Overall, hyperopia was present in 7.7% of children and myopia in 7.4%. Hyperopia was associated with female gender. Myopia was more common in children of fathers with higher levels of education. CONCLUSIONS: Reduced vision because of uncorrected refractive error is a major public health problem in urban school-aged children in India. Cost-effective strategies are needed to eliminate this easily treated cause of vision impairment.