NOD小鼠视网膜VEGF表达和视网膜细胞凋亡

目的:研究NOD小鼠早期糖尿病视网膜VEGF表达和视网膜细胞凋亡情况,以及二者间的关系。方法:NOD小鼠分为对照组(非糖尿病小鼠)(2,4,6,8,12wk组,n=30)和糖尿病组(2,4,6,8,12wk组,n=30)。每组小鼠在规定时间处死,提取血液标本,摘除眼球,分离视网膜备用。ELISA法检测视网膜VEGF和血液VEGF。透射电子显微镜检测小鼠视网膜细胞凋亡情况。结果:糖尿病组血液和视网膜VEGF表达与对照组相比明显增高(12wk,血液标本:4.9±0.4μg/gvs0.19±0.1μg/g,P<0.01;视网膜,165.0±9.0μg/gvs18.0±4.0μg/g,P<0.01)。NOD小鼠早期糖尿病视网膜VEGF表达和血液VEGF表达呈正相关(γ=0.9902,P=0.001)。糖尿病组视网膜神经节细胞和血管内皮细胞凋亡明显增加P<0.01。结论:视网膜VEGF表达增加可能与视网膜凋亡增多有关。早期糖尿病NOD小鼠视网膜VEGF表达增加是多因素的。     

非肥胖性糖尿病小鼠的早期视网膜病变

目的:研究早期糖尿病视网膜病变的小鼠模型。方法:NOD小鼠随机分为正常对照组(4,12wk组,n=8)和糖尿病组(4,12wk组,n=12),每组取4wk和12wk处死小鼠,光镜和电镜观察视网膜结构的改变。结果:糖尿病组4wk时毛细血管基底膜增厚,可见内皮细胞、周细胞和神经节细胞超微结构改变。12wk时基底膜明显增厚,内皮细胞、周细胞和神经节细胞凋亡增加。结论:在糖尿病早期发生了视网膜神经元细胞超微结构病变和微血管病变。     

早期非肥胖性糖尿病小鼠视网膜细胞凋亡

目的:观察糖尿病早期视网膜细胞凋亡情况.方法:NOD雌鼠随机分为糖尿病组(n=10)和正常对照组(n=10),每组在4 wk和12 wk处死小鼠,摘除眼球并制作组织切片,用TUNEL法检测视网膜细胞的凋亡.电镜观察视网膜超微结构改变.结果:视网膜神经元病变和微血管病变在糖尿病早期都有发生,糖尿病组视网膜神经节细胞和内皮细胞凋亡数目明显较对照组增多(P＜0.01).结论:视网膜神经元凋亡可促进视网膜神经元病变的发生和发展.     

白细胞淤滞对糖尿病视网膜病变作用的研究

目的:观察糖尿病小鼠视网膜血管内白细胞淤滞和细胞间黏附因子-1(ICAM-1)在视网膜的表达.方法:选取C57型小鼠45只,随机分为2组:糖尿病组22只、正常组23只.10wk后取视网膜,荧光显微镜计数小鼠全视网膜微血管内淤滞的白细胞数目及其含有ICAM-1表达的荧光小球数目,免疫蛋白印迹法检测视网膜血管内皮生长因子(VEGF)和ICAM-1的表达.结果:10wk后,糖尿病小鼠视网膜血管内白细胞数目及含有ICAM-1表达的荧光小球数目明显高于正常对照组(P<0.01),其视网膜内VEGF和ICAM-1明显增加,有统计学意义(P<0.05).结论:视网膜血管内白细胞淤滞与糖尿病视网膜病变(DR)早期的视网膜毛细血管无灌注有关.     

贝那普利对糖尿病大鼠视网膜微血管病变的保护作用

目的:探讨贝那普利(benazepril,BZ)对糖尿病大鼠视网膜微血管病变的保护作用及机制。方法:链脲佐菌素ip制备糖尿病大鼠模型,分为糖尿病组(DM)、贝那普利治疗组(BZ),同时设立正常对照组(Con)。治疗组每天灌胃给予BZ10mg/kg。24wk后放射免疫法测定血浆AngⅡ水平,免疫组织化学法和Westernblot技术检测视网膜VEGF蛋白表达,透射电镜观察视网膜血管基底膜厚度变化。结果:与Con组相比,DM组大鼠血浆AngⅡ水平明显增高(P<0.01),视网膜VEGF蛋白表达显著增强(P<0.01),视网膜微血管基底膜明显增厚;与DM组相比,BZ治疗后大鼠血浆AngⅡ水平明显降低(P<0.05),视网膜VEGF蛋白表达则显著减弱(P<0.01),视网膜微血管基底膜增厚明显减轻。结论:BZ可通过抑制血浆AngⅡ水平,减少糖尿病大鼠视网膜组织VEGF表达,抑制视网膜微血管基底膜增厚。     

坎地沙坦对糖尿病大鼠视网膜VEGF和MCP-1表达的影响

目的:研究血管紧张素Ⅱ受体拮抗剂坎地沙坦对糖尿病(DM)大鼠视网膜组织VEGF和MCP-1表达的影响。方法:链脲佐菌素(STZ)制备DM大鼠动物模型36只,随机分为DM模型组和坎地沙坦治疗组,另取18只正常SD大鼠作为正常对照组,每组均随机分为4,8,12wk3个亚组。视网膜铺片联合PAS染色观察视网膜微血管形态学变化,应用SABC免疫组织化学法检测坎地沙坦对大鼠视网膜组织VEGF和MCP-1表达的影响。结果:正常对照组视网膜血管网结构清晰,走行规则;DM模型组血管迂曲阻塞,走行不规则;治疗组见血管网迂曲情况较模型组明显改善,走行较规则。在对照组和模型4wk组中大鼠视网膜组织无VEGF和MCP-1阳性表达或只呈弱阳性表达;模型8wk和12wk组两者阳性表达明显增强,且随着病程延长呈递增趋势。治疗组两者的表达则均较同时期模型组明显减弱,差异有统计学意义(P<0.05)。结论:研究血管紧张素Ⅱ受体拮抗剂坎地沙坦可降低DM大鼠视网膜VEGF和MCP-1的表达。     

胰岛素控制血糖对糖尿病大鼠早期视网膜血管的影响

目的:探讨胰岛素控制血糖对糖尿病早期大鼠视网膜血管形态改变和血管内皮细胞生长因子(Vascular endothelial growth factor,VEGF)表达的影响。方法:实验动物Wistar大鼠分正常对照组、糖尿病组、糖尿病血糖严格控制组和糖尿病血糖非严格控制组。链尿佐菌素(Streptozotocin,STZ)诱导糖尿病动物模型,动物成模3周后糖尿病血糖严格控制组及血糖非严格控制组大鼠予胰岛素治疗,20d后处死,行Fluorescein isothiocyanate-dextran(FITC-Dextran)灌注视网膜血管铺片观察大鼠视网膜血管形态变化,并行VEGF免疫荧光染色观察大鼠视网膜VEGF的表达改变。结果:FITC-Dextran灌注示糖尿病血糖非严格控制组大鼠视网膜浅层血管多处荧光素聚集,不均匀分布,深层毛细血管局部扩张、迂曲;血糖严格控制组视网膜血管管径较均匀一致,无局部扩张或狭窄。糖尿病血糖非严格控制组VEGF高表达,血糖严格控制组较糖尿病组、血糖非严格控制组视网膜VEGF表达下降,统计学比较具有显著性差异(P<0.05)。结论:胰岛素治疗严格控制血糖至正常水平可以降低糖尿病早期大鼠视网膜VEGF的表达、减轻视网膜血管损害;血糖波动会加重糖尿病视网膜病变的发展。眼科学报2007;23:205-211.     

糖尿病早期大鼠视网膜神经细胞凋亡与caspase-3表达的关系

目的:观察糖尿病早期大鼠,视网膜神经细胞凋亡与caspase-3表达变化的关系。方法:健康雄性8周龄SD大鼠36只,建立糖尿病大鼠模型18只,正常对照18只。再各自分为4,8,12wk3组,每组6只大鼠。TdT介导DNA缺口末端的dUTP标记(TUNEL)法检测视网膜神经细胞的凋亡程度;免疫组织化学方法检测半胱氨酸天冬氨酸蛋白酶3(caspase-3)蛋白表达水平,实时荧光定量聚合酶链反应(PCR)法检测caspase-3mRNA表达情况。结果:正常对照组4,8,12wk大鼠均未见视网膜神经细胞凋亡。糖尿病组大鼠于建模后4wk即出现视网膜神经细胞凋亡,8wk和12wk大鼠视网膜神经凋亡程度较同期正常对照组大鼠均明显增强。神经细胞凋亡主要位于视网膜神经节细胞层及内核层。正常对照组4,8,12wk大鼠视网膜均未见caspase-3蛋白阳性表达,糖尿病组大鼠4wk即可见caspase-3蛋白阳性表达,8和12wk时表达增强。正常对照组4,8,12wk大鼠caspase-3mRNA表达RQ值分别为1.6±0.6,1.5±0.5,1.6±0.3;糖尿病组4,8,12wk大鼠caspase-3mRNA表达RQ值分别为5.7±1.2,12.6±2.3,14.3±2.1;较同期对照组均明显升高,差异有统计学意义(P<0.05)。结论:糖尿病早期视网膜神经细胞凋亡可能与capase-3表达增强有关。     

早期糖尿病NOD小鼠视网膜HIF-1的表达

目的:探讨糖尿病NOD小鼠视网膜HIF-1α的表达。方法:NOD小鼠随机分为正常对照组和糖尿病组,分别于糖尿病2、4、6、8和12周处死正常对照组和糖尿病组小鼠,摘除眼球后分离视网膜。Westernblot方法检测视网膜HIF-1α的表达,免疫组化方法检测视网膜上HIF-1α的表达。结果:与正常对照组相比,糖尿病组小鼠血糖明显增高,体重明显下降(P<0.01);Westernblot显示糖尿病6周时视网膜HIF-1α低水平表达,12周时HIF-1α表达增高;免疫组化显示糖尿病组12周时视网膜内层HIF-1α表达增加,而未见视网膜外层HIF-1α表达。结论:糖尿病早期视网膜HIF-1α表达增高,说明在糖尿病早期视网膜发生缺血缺氧;HIF-1α可能参与了糖尿病早期视网膜缺血缺氧的继发损害过程。     

双丹明目胶囊对DR大鼠视网膜血管形态学及VEGF表达的影响

目的:观察糖尿病视网膜病变大鼠模型视网膜血管的病理变化及VEGF表达变化,初步评价双丹明目胶囊抑制视网膜血管新生效应。方法:将双丹明目胶囊作用于糖尿病视网膜病变大鼠,通过与正常组、模型对照组、阳性对照组的比较,电镜下观察双丹明目胶囊对糖尿病视网膜病变大鼠视网膜组织的影响,HE染色后光镜下观察视网膜结构,并采用免疫组织化学法检测大鼠视网膜中VEGF的表达。结果:经双丹明目胶囊治疗2mo后,双丹明目组大鼠视网膜组织轻度水肿,毛细血管周细胞水肿,线粒体轻度肿胀,结构稍欠清晰,部分内皮细胞轻度增生。除正常组外各组视网膜VEGF表达增加,以模型对照组最为明显,且双丹明目组和阳性对照组与模型对照组VEGF的表达有明显差异(P<0.01)。结论:双丹明目胶囊能有效地改善糖尿病大鼠视网膜微血管改变,减轻视网膜各层结构水肿、坏死情况,改善超微结构改变,可以抑制DR大鼠视网膜VEGF表达。     

Homeostasis of the retinal micro-environment: I. Magnesium,potassium and calcium distributions in the avian eye

The concentrations of Mg²⁺, K⁺ and Ca²⁺ in the intraocular fluids (IOFs) and blood plasma of chickens and pigeons were determined by atomic absorption spectrophotometry. The Mg²⁺ concentration in the IOFs of both species was greatest in the liquid vitreous adjacent to the retina followed by aqueous > blood plasma > plasma dialysate. In contrast the concentration of K⁺ in the IOFs of both chickens and pigeons was greater in the aqueous than in the liquid vitreous. The concentrations of Ca²⁺ in all IOF compartments of chicken eyes were virtually identical and were lower than that of blood plasma. The concentrations of Mg²⁺ in the IOFs of the chicken, especially in the liquid vitreous, was remarkably stable; experimentally lowering or raising the plasma Mg²⁺ concentration over a relatively wide range had little or no effect on the Mg²⁺ concentration in the IOFs of these animals. We can conclude that a high Mg²⁺ and low K⁺ concentration in the extracellular fluids of the retina is maintained in the avian eye, as in the mammalian eye, by active transport processes across the blood-retinal barrier systems. Because the avian retina is completely avascular, the site of these homeostatic transport processes must be the epithelium of the retinal choroid and/or the pecten. These findings support the concept that the contribution of the vitreous to the homeostasis of the retinal micro-environment is inversely related in vertebrates to the degree of retinal vascularization.     

Vergleich der Durchmesserreaktion retinaler Arterien und Venen auf Flickerlicht

ZusammenfassungZiel In dieser Studie soll die durch Flickerlicht verursachte Durchmesserreaktion retinaler Arterien und Venen hinsichtlich Ausmaß und zeitlichem Ablauf verglichen werden.Methoden In die klinische Studie wurden 26 gesunde Probanden einbezogen. Der Durchmesser der retinalen Gefäße jeweils eines Auges wurde kontinuierlich mittels eines Retinal vessel analyzer gemessen. Jede Untersuchung bestand aus 100 s Baseline sowie 5 Perioden von 20 s Flickerlichtstimulation, gefolgt von 80 s Beobachtung.Ergebnisse Unmittelbar nach Flickerlicht dilatierten die Arterien um 6,9±2,8% (MW±STD) und die Venen um 6,5±2,8% (Unterschied nicht signifikant). Der Quotient aus arterieller und venöser Dilatation (AVDQ) betrug 1,25±0,69 (Spannweite 0,2 bis 2,8). Es konnte keine signifikante Altersabhängigkeit der arteriellen bzw. venösen Dilatation oder des AVDQ nachgewiesen werden. Die arterielle Dilatation ging nach 25,9±10,8 s in eine leichte Konstriktion von –2,7±1,4% über. Im Gegensatz dazu waren die Venen zum Zeitpunkt des individuellen Konstriktionsmaximums noch um 0,5±1,3% dilatiert (p<0,001).Schlussfolgerungen Die flickerlichtinduzierte Durchmesserreaktion retinaler Arterien und Venen unterscheidet sich bei Gesunden nicht in ihrem mittleren dilatativen Maximum, aber in Form und zeitlichem Verlauf des Abklingens der Dilatation.Unterstützung durch: BMBF 13N7999.Vortrag gehalten auf der 101. Jahrestagung der DOG, Berlin, September 2003.     

Acute Multifocal Placoid Pigment Epitheliopathy Associated with Cavernous Sinus Thrombosis

Acute multifocal placoid pigment epitheliopathy (AMPPE) has been associated with disease of the central nervous system. In this case report, we discuss a patient presenting with AMPPE in the setting of a new central nervous system association: cavernous sinus thrombosis.     

Dual nonlinearities regulate contrast sensitivity in pattern discrimination tasks

Many current psychophysical models propose that visual processing in cortex is hierarchical, with nonlinearities sandwiched between linear stages of processing. In earlier publications, we proposed a model of this type to account for masking effects found with spatial frequency and orientation discriminations. Our model includes two nonlinear mechanisms that regulate contrast sensitivity in early cortical mechanisms. The first is a local within-pathway nonlinearity that accelerates at low contrasts but is compressive at high. The second is a pooled nonlinear gain control process that operates over a broad range of neurons with different tuning characteristics. Here, we test predictions of the model for spatial frequency discriminations. The model predicts that at low contrasts, adding a grating mask oriented parallel to test gratings will improve discrimination performance via operation of the within-pathway nonlinearity, analogous to the "dipper effect" found with contrast discriminations. Adding an orthogonally oriented mask is predicted to have no effect at low contrasts, where pooled gain control processes contribute little to performance. At high contrasts, the model predicts that performance will asymptote and become independent of contrast with either parallel or orthogonal masks. The results confirm model predictions.