蛋白激酶C活性调节剂对豚鼠近视眼视网膜Mtiller细胞的作用及意义

目的研究蛋白激酶C（PKC）激活剂PMA和抑制剂GF109203X对豚鼠近视眼视网膜Mailer细胞生长状态及PKC蛋白表达的影响。方法眼罩遮盖诱导近视模型,酶消化法培养其视网膜Mailer细胞,并鉴定。PMA、GF109203X分别干预近视眼Mailer细胞。MTT测细胞活力,TUNEL染色检测凋亡细胞,Westren blotting测PKC蛋白表达。结果95％以上的培养细胞阳性表达胶质纤维酸性蛋白（GFAP）和波形蛋白（Vimentin）。近视组PKC蛋白表达较正常组上调（P〈0．05）。PMA、GF109203X均能引起近视眼Mailer细胞的抑制率升高和诱导其凋亡（P〈0．05）。PMA诱导近视眼Mailer细胞PKC蛋白表达进一步上调,100nmol／L组和1000nmol／L组表达量高于10nmol／L组（P〈0．05）。1μmol／L和10μmol／L GF109203X均能引起近视眼Mailer细胞PKC蛋白表达下调,10μmol／L的抑制作用大于1μmol／L（P〈0．05）。结论PKC蛋白在豚鼠近视眼视网膜Mailer细胞表达升高,且其表达受PMA和GF109203X调控。     

蛋白激酶C活性调节剂对豚鼠近视眼视网膜Mller细胞的作用及意义

目的研究蛋白激酶C（PKC）激活剂PMA和抑制剂GF109203X对豚鼠近视眼视网膜Mailer细胞生长状态及PKC蛋白表达的影响。方法眼罩遮盖诱导近视模型,酶消化法培养其视网膜Mailer细胞,并鉴定。PMA、GF109203X分别干预近视眼Mailer细胞。MTT测细胞活力,TUNEL染色检测凋亡细胞,Westren blotting测PKC蛋白表达。结果95％以上的培养细胞阳性表达胶质纤维酸性蛋白（GFAP）和波形蛋白（Vimentin）。近视组PKC蛋白表达较正常组上调（P〈0．05）。PMA、GF109203X均能引起近视眼Mailer细胞的抑制率升高和诱导其凋亡（P〈0．05）。PMA诱导近视眼Mailer细胞PKC蛋白表达进一步上调,100nmol／L组和1000nmol／L组表达量高于10nmol／L组（P〈0．05）。1μmol／L和10μmol／L GF109203X均能引起近视眼Mailer细胞PKC蛋白表达下调,10μmol／L的抑制作用大于1μmol／L（P〈0．05）。结论PKC蛋白在豚鼠近视眼视网膜Mailer细胞表达升高,且其表达受PMA和GF109203X调控。     

内皮素刺激下人视网膜色素上皮细胞的自分泌

以往实验发现，在人视网膜脱离玻璃体液中和检测出内皮素（ET-1）的含量增生膜中的表达，说明ET-1参与了增生性玻璃体视网膜病变（PVR）的形成。ET-1可以刺激自身的分泌，是一种正反馈调节，可以激活丝裂素活化蛋白激酶级联反应途径转录ET-1 mRNA。我们对培养的人视网膜色素上皮（RPE）细胞经ET-1的刺激，观察其自身的分泌和调节，现报告如下。     

双靶点干预对糖尿病大鼠视网膜中血管内皮生长因子和结缔组织生长因子基因表达的影响

目的 观察糖尿病大鼠视网膜中以及双靶点干预后血管内皮生长因子（VEGF）和结缔组织生长因子（CTGF）mRNA表达变化。方法 Sprague-Dawley大鼠48只,随机分为正常对照组（CON1组）和糖尿病（DM）组。经鼠尾静脉注射链脲佐菌素制作糖尿病大鼠模型。建模后8、10、12周取大鼠视网膜标本行逆转录实时定量聚合酶链反应（RT-PCR）检测VEGF、CTGF mRNA表达变化。根据上述结果,选取相同条件的大鼠60只,随机选择50只大鼠依照上述方法建立糖尿病大鼠模型;10只大鼠为正常对照组（CON2组）。建模后第10周,将糖尿病大鼠随机分为双靶点干预组、ranibizumab单靶点干预组、CTGF小发夹RNA（shRNA)单靶点干预组、DM未干预组。干预1周后取各组大鼠视网膜标本,行实时定量RT-PCR检测VEGF、CTGF mRNA表达变化。结果 建模后第8周,DM组大鼠视网膜CTGF mRNA水平显著增高且一直持续到第12周,与CON1组比较,差异均有统计学意义（t=-2.49、-2.67、-2.42,P＜0.05）;第8周时DM组大鼠视网膜VEGF mRNA水平与CON1组比较,差异无统计学意义（t=-0.443,P=0.669）;第10周时显著上调且一直维持到第12周,与CON1组比较,差异有统计学意义（t=-2.35、-2.57,,P＜0.05）。 Ranibizumab单靶点干预组大鼠视网膜VEGF mRNA表达水平较DM未干预组显著降低,差异有统计学意义（t=-3.44,P＜0.05）,与CON2组比较,差异无统计学意义(t=-1.37,P＞0.05);CTGF mRNA表达显著高于DM未干预组,差异有统计学意义（t=2.48,P＜0.05）。CTGF shRNA单靶点干预组大鼠视网膜CTGF、VEGF mRNA表达均较DM未干预组显著降低,差异有统计学意义（t=0.23、-2.92,,P＜0.05）。双靶点干预组大鼠视网膜VEGF、CTGF mRNA表达均下调,与DM未干预组比较,差异均有统计学意义（t=-6.09、-5.11,,P＜0.001）;与CON2组比较,差异无统计学差异（t=-1.16、1.139,,P＞0.05）。结论 早期DM大鼠视网膜内VEGF、CTGF基因表达即升高,且CTGF升高较VEGF早。Ranibizumab结合CTGF shRNA双靶点干预能同时降低VEGF、CTGF基因在DM大鼠视网膜中的表达。     

基质金属蛋白酶抑制剂GM6001对糖尿病大鼠血-视网膜屏障的影响

背景 研究表明,多种基质金属蛋白酶（MMPs）家族成员在糖尿病视网膜病发（DR）的发病过程中发挥作用,但是否MMPs抑制剂能改善MMPs对血-视网膜屏障（BRB）的破坏作用尚不十分清楚.目的 探讨人工合成MMPs抑制剂GM6001对糖尿病大鼠BRB的影响.方法 24只成年清洁级SD大鼠按随机数字表法随机分为对照组、糖尿病组和糖尿病＋GM6001组.采用链脲佐菌素诱导腹腔内注射法诱导大鼠糖尿病模型,对照组以相同的方法注射等体积枸橼酸盐缓冲液.造模成功后3d和14d,糖尿病＋GM6001组大鼠玻璃体腔内注射10μl（100tμmol/L）GM6001各1次,对照组和糖尿病组大鼠以相同的方法注射等体积生理盐水.注射后1个月摘取大鼠一侧眼球,采用逆转录PCR（RT-PCR）法检测大鼠视网膜中MMP-2 mRNA和MMP-9 mRNA的相对表达量;用伊文思蓝（EB）灌注大鼠右侧颈静脉,120 min后以约120 mmHg（1 mmHg=0.133 kPa）的灌注压于大鼠左心室灌注枸橼酸钠缓冲液配制的质量分数1％多聚甲醛溶液,2 min后摘取大鼠另一侧眼球,观察大鼠视网膜EB的渗漏量.结果 RT-PCR检测显示MMP-2、MMP-9和GAPDH的反应条带分别位于436、536和484 bp.3个组大鼠视网膜中MMP-2 mRNA和MMP-9 mRNA相对表达量总体差异均有统计学意义（F=20.336,P=0.000;F=8.742,P=0.002）;其中糖尿病组和糖尿病＋GM6001组大鼠视网膜中MMP-2 mRNA和MMP-9 mRNA的相对表达量明显高于对照组大鼠,差异均有统计学意义（P＜0.01）,而糖尿病＋GM6001组大鼠视网膜中MMP-2 mRNA和MMP-9 mRNA的相对表达量明显低于糖尿病组大鼠,差异均有统计学意义（P=0.01、0.02）.对照组、糖尿病组和糖尿病＋GM6001组大鼠视网膜中标准化EB质量分数分别为（12.60±3.50）、（26.52±7.14）和（17.55±2.65） ng/mg,总体差异有统计学意义（F=17.032,P＜0.01）,其中糖尿病组大鼠视网膜中标准化EB质量分数值明显高于对照组,而糖尿病＋GM6001组较糖?     

重组腺相关病毒载体介导的色素上皮衍生因子对糖尿病大鼠视网膜的影响

目的以重组腺相关病毒载体（rAAV）介导色素上皮衍生因子（PEDF）转染糖尿病大鼠视网膜，观察其表达及其对血管内皮生长因子（VEGF）和视网膜微血管的影响。方法 雄性 Wister大鼠链脲佐菌素腹腔注射诱导糖尿病模型。随机分为1（DM1）、3（DM3）、6（DM6）个月组。右眼玻璃体注射rAAV2-CMV-hPEDF作为治疗组，左眼注射rAAV2-CMV-GFP作为自身对照眼。正常大鼠右眼假注射，左眼不注射。应用半定量逆转录聚合酶链反应和Western blot测定VEGF和PEDF的mRNA和蛋白的表达情况，应用视网膜血管铺片观察视网膜微血管的变化。结果注射后大鼠治疗眼视网膜hPEDF mRNA表达不断增强，持续到6个月，达到顶峰。PEDF蛋白表达亦不断增加，与同时间点对照眼相比差异有统计学意义（t=4.292，10.721，16.692；P＜0.01）。治疗组各时间点视网膜VEGF mRNA及蛋白表达量相互间无统计学意义（t=1.621，0.698，0.758；P＞0.05），均显著高于正常对照组（t=5.171，6.857，7.542；P＜0.05），但与同时间点自身对照眼相比表达显著降低（t=2.343，3.263，4.455；P＜0.01）。糖尿病大鼠治疗眼与自身对照眼视网膜微血管形态在1个月时与正常对照组视网膜相比无显著差异，但3个月与6个月时治疗眼与自身对照眼相比视网膜毛细血管损伤改变明显减轻。结论 rAAV2-CMV-hPEDF玻璃注射可增加糖尿病大鼠视网膜PEDFmRNA和蛋白水平表达，改善其早期视网膜微血管的损害，并抑制VEGF的表达，其调节在mRNA水平。 （中华眼底病杂志，2008，24：259-264）     

糖尿病大鼠视网膜血管内皮细胞p53、bcl-2及生长因子的表达与细胞周期阻滞

目的 观察p53、bcl-2、bax基因、血管内皮细胞生长因子（vascular endothelial cell growth factor, VEGF）、碱性成纤维细胞生长因子（basic fibro blast gro wth factor, bFGF）、胰岛素样生长因子-I（insulin-like growth factor-I, IGF-I ）及其受体在1～20周糖尿病大鼠视网膜血管内皮细胞(vascular endothelial cell, VECs) 的表达以及与细胞周期阻滞的关系。 方法 四氧嘧啶(alloxan)诱导制作糖尿病大鼠模型；免疫组织化学染色，光、电镜观察；斑点印迹（dot blotting）测定p53、bcl-2 mRNA；Western 印迹（Western blotting）测定p53、bcl-2蛋白。 结果 免疫组织化 学染色后光学显微镜观察显示8～20周糖尿病大鼠视网膜节细胞层、内核层的各类血管都呈p53、bcl-2免疫阳性反应。电镜观察显示阳性反应物沉淀在VECs。VECs同时为VEGF、bFGF、IGF-I蛋白及其受体阳性反应。视网膜内其它细胞及同窝对照大鼠和1～6周病程糖尿病大鼠视网膜所有细胞均未见上述蛋白阳性反应。Dot blotting测定结果显示，20周糖尿病大鼠视网膜组织有p53和bcl-2 mRNA表达。Western blotting测定证实20周糖尿病大鼠视网膜表达p53和bcl-2 蛋白。对照组及1 ~ 20周糖尿病大鼠视网膜内未见bax阳性反应物。 结论 p53、bcl-2可能参与介导糖尿病大鼠视网膜VECs周期阻滞。高糖刺激生长因子VEGF、bFGF、IGF-I及其受体的表达，生长因子可能通过自分泌途径维持VECs存活。 （中华眼底病杂志，2003，19：29-33）     

PKC对豚鼠近视眼视网膜Mller细胞近视因子基因的调控作用

目的研究蛋白激酶C（PKC）对豚鼠近视眼视网膜Mtiller细胞中酪氨酸羟化酶（TH）、诱导型NO合成酶（iNOS）、神经型NO合成酶（nNOS）、碱性成纤维细胞生长因子（bFGF）、转化生长因子B（TGFl3）基因表达的调控作用。方法眼罩遮盖法建立豚鼠近视眼模型,酶消化法原代培养其视网膜Müller细胞,GFAP免疫组织化学染色进行细胞鉴定。根据干预因素不同,把Müler细胞分为正常对照组、近视组、近视＋GF109203X组、近视＋PMA组和近视＋DMSO组。RT—PCR检测TH、iNOS、nNOS、bFGF和TGFβmRNA的表达情况。结果与正常对照组比较,近视眼视网膜Mtiller细胞iNOS、nNOS、bFGF和TGFβmRNA表达上调,THmRNA表达下调（P〈0．05）。PKC激活剂（PMA）激活PKC后,近视眼视网膜Müller细胞表达nNOS、iNOS、TH和bFGFmRNA上调（P〈0．05）;GF109203X抑制PKC活性后,这些因子的mRNA表达下调（P〈n05）。结论豚鼠近视眼视网膜Müller细胞nNOS、iNOS、bFGF和TH基因的表达受PKC调控,Müller细胞可能为近视信号因子的一个重要来源。     

巴曲酶对糖尿病大鼠血视网膜屏障和视网膜血管内皮生长因子表达的影响

目的 研究巴曲酶对糖尿病大鼠血视网膜屏障以及视网膜血管内皮生长因子（VEGF）表达的影响。 方法 将60只大鼠用链尿佐菌素腹腔注射制成糖尿病大鼠模型，分成糖尿病组（n＝20）、40mg/kg巴曲酶注射组（n＝20）和20 mg/kg巴曲酶注射组（n＝20）。另25只正常大鼠为正常对照组。7d 后处死全部大鼠，通过伊凡思蓝法观察各组大鼠血视网膜屏障情况，酶连免疫吸附法分析视网膜总蛋白中的VEGF含量，比较各组结果。 结果 正常对照组大鼠视网膜内渗漏的伊凡思蓝含量明显低于另外3个糖尿病大鼠组（P<0.01）,不同剂量巴曲酶治疗组之间伊凡思蓝含量无明显差异（P>0.05），巴曲酶治疗的2组大鼠伊凡思蓝含量均比糖尿病组大鼠低（P<0.05）。正常对照组大鼠、不同剂量巴曲酶注射的2组大鼠视网膜内VEGF含量明显低于糖尿病大鼠（P<0.01）；正常对照组视网膜内VEGF含量与20 mg/kg巴曲酶注射组比较无明显差异（P＝0.06）；40mg/kg 巴曲酶注射组视网膜内VEGF含量比正常对照组低(P＝0.01)；不同剂量的巴曲酶治疗组之间VEGF含量无明显差异（P＝0.78）。 结论 巴曲酶治疗减轻了糖尿病大鼠血视网膜屏障功能的损伤，降低了VEGF的表达，提示巴曲酶对糖尿病大鼠血视网膜屏障功能有一定的保护作用。 (中华眼底病杂志, 2006, 22: 16-19)     

Delta样配体4单克隆抗体对视网膜新生血管形成和血管内皮生长因子表达的影响

背景 Delta样配体4(Dll4)参与视网膜内细胞的发育和血管的发生过程,并与血管内皮生长因子(VEGF)共同参与诱导和挑选尖端细胞的过程.Dll4在视网膜新生血管形成中的作用及其与VEGF表达的关系值得关注. 目的 研究Dll4单克隆抗体玻璃体腔内注射后对视网膜中Dll4、VEGF及其受体表达和视网膜新生血管形成的影响.方法 将5日龄的新生SPF级SD大鼠与母鼠一起在含体积分数为(80±2)％氧气的密闭玻璃箱内饲养至12日龄,然后返回自然环境下饲养至17日龄以建立大鼠氧诱导视网膜病变(OIR)模型.于模型大鼠12日龄时右眼玻璃体腔内注射Dll4单克隆抗体2.5 μl(0.5 μg)为Dll4单克隆抗体注射组,左眼以同样的方式注射等体积PBS作为PBS对照组.于大鼠17日龄时处死大鼠并分离视网膜.应用逆转录PCR(RT-PCR)法检测两组大鼠视网膜中Dll4、VEGF、VEGF受体-1(VEGFR-1)、VEGFR-2、神经纤维网蛋白-1(neuropilin-1)mRNA的表达情况,采用视网膜铺片ADP酶染色法观察大鼠视网膜新生血管形态,采用视网膜切片苏木精-伊红染色法计数突破内界膜的血管内皮细胞核数目,评估新生血管的严重程度.两组间各检测指标的差异比较采用配对t检验. 结果 Dll4单克隆抗体注射组大鼠视网膜内Dll4 mRNA表达灰度值(Dll4 mRNA/β-actin mRNA)为0.22±0.06,明显低于PBS对照组的0.98±0.13,差异有统计学意义(t=21.839,P=0.000),而2个组间VEGF mRNA及其受体VEGFR-1 mRNA、VEGFR-2 mRNA表达灰度值的差异均无统计学意义(t=0.463,P=0.649;t=1.687,P=0.109;t=-1.674,P=0.111);与PBS对照组比较,Dll4单克隆抗体注射组小鼠视网膜中neuropilin-1 mRNA的表达量明显升高,差异有统计学意义(0.73±0.08 vs.0.64±0.07)(t=-2.677,P=0.015).Dll4单克隆抗体注射组大鼠视网膜新生血管密度明显高于PBS对照组.Dll4单克隆抗体注射组大鼠视网膜突破内界膜的血管内皮细胞数为(63.6±11.6)个/张,PBS对照组为(35.1±5.2)个/张,差异有统计学意义(t=-7.879,P=0.000). 结论 Dll4在视网膜新生血管形成的过程中发挥重要作用,并可能通过对VEGFR的反馈抑制发挥抑制病理性新生血管过度形成的作用.     

Role of protein kinase C on the alteration of retinal endothelin-1 in streptozotocin-induced diabetic rats

Activation of protein kinase C (PKC) has been implicated in the pathogenesis of diabetic retinopathy. The purpose of this study was to investigate the role of PKC on the alteration of retinal endothelin-1 in 2-week streptozotocin (STZ)-induced diabetic rats. The measurement of retinal PKC activities from membranous and cytosolic fractions was conducted by ELISA. Retinal tissues were analysed for the expression of endothelin-1 (ET-1), endothelin-3 (ET-3), endothelin-A (ET-A), and endothelin-B (ET-B) mRNA by means of semi-quantitative RT-PCR. Retinal vasculature isolated by trypsin digest technique was immunostained for ET-1. We followed the alteration of retinal ET-1 after intravitreal injection of a general PKC inhibitor, GF109203X, in 2-week diabetic rats. Retinal PKC specific activities were significantly increased by 37% (P=0.027) in the membranous fraction in diabetic rats compared with normal rats, whereas PKC specific activities in the cytosolic fraction were unchanged. The retina from the diabetic rats showed increased ET-1 mRNA expression after 2 weeks, while no changes were found for ET-3, ET-A and ET-B. ET-1 immunoreactivity was also increased in the retinal vasculature of diabetic rats. Retinal ET-1 expression was decreased after intravitreal injection of GF109203X (10(-5), 10(-6), 10(-7) M) in a dose-dependent manner. The results from this study showed that the enhanced ET-1 expression associated with the activation of PKC has occurred in early diabetes, and PKC inhibitor could reverse the up regulation of ET-1.     

Endothelin-1 and endothelin receptors in light-induced retinal degeneration

We have studied the distribution of endothelinergic molecules: prepro-endothelin-1 (PPET-1), endothelin-1 (ET-1), and receptors A and B (ET-A) and (ET-B) in the retina of mice. The localization of these molecules in normal mice was compared to their localization in retinas from animals submitted to continuous illumination during 1, 6, 9 or 18 days. We also evaluated the distribution of smooth muscle actin (SMA) and glial markers, glial fibrillary acidic protein (GFAP) and glutamine synthase (GS). PPET-1 immunoreactivity mainly appeared in retinal pigment epithelium (RPE) and cells of the ganglion cell layer (GCL), whereas ET-1 immunoreactivity was present in the RPE, outer plexiform layer (OPL) and astrocytes. Astrocytes exhibited the strongest immunostaining in the retina. ET-A immunoreactivity was observed in endothelium, RPE, OPL and cells of the GCL. By contrast, ET-B immunoreactivity could be detected in endothelial cells, horizontal cells and astrocytes. Astrocytes of the optic nerve also exhibited ET-1, ET-A, and ET-B immunoreactivities. After light-induced degeneration, there was an increase of RPE immunostaining. Degeneration of photoreceptors was accompanied by disappearance of immunoreactivity in the OPL. However, ET-A immunoreactivity appeared in the amacrine sublayer of the INL. There was an enormous increase in astrocytes and its cell processes. The increase of astrocytic immunoreactivities for ET-1 and ET-B was confirmed by quantitative image analysis. Growth of astrocytic cell processes was most marked around retinal blood vessels. Our findings indicate that there are at least three endothelinergic pathways in the normal retina: (1) between the RPE and choriocapillaris, (2) at the OPL, and (3) between blood vessels, astrocytes and cells of the GCL. After light-induced degeneration of photoreceptors, endothelinergic molecules were overexpressed at the RPE and astrocytes, but mostly disappeared from the OPL.     

Endothelin-3 regulation of retinal hemodynamics in nondiabetic and diabetic rats

PURPOSE: To investigate the mechanisms of action of endothelin (ET)-3 on the regulation of retinal hemodynamics in diabetic and nondiabetic rats. METHODS: Retinal blood flow changes were measured using video fluorescein angiography. Measurements were made before and after intravitreal injections of different ET-3 concentrations in nondiabetic rats and rats with streptozotocin (STZ)-induced diabetes. The effect of ET-3 on retinal blood flow was also investigated in nondiabetic rats after pretreatment with N:(G)-monomethyl-L-arginine (L-NMMA), a nitric oxide synthase (NOS) inhibitor; BQ-788, an ET receptor B (ETB) antagonist; and BQ-123, an ET receptor A (ETA) antagonist. Control animals were injected intravitreally with vehicle alone. RESULTS: In nondiabetic rats, ET-3 induced a dose-dependent rapid increase in retinal blood flow 2 minutes after intravitreal injection (maximal at 10(-)(8) M, P < 0. 01) followed 15 and 30 minutes after ET-3 injection by dose-dependent decreases in retinal blood flow (maximal effect at 10(-)(6) M, P < 0.05). The ET-3-stimulated retinal blood flow increase was inhibited by 10(-)(4) M BQ-788 (P < 0.01) and 10(-)(3) M L-NMMA (P < 0.05). The ET-3-stimulated decrease in retinal blood flow at later times (15 minutes) was inhibited (P < 0.03) by 10(-4) M BQ-123. In diabetic rats, baseline retinal blood flows were decreased compared with nondiabetic rats (P < 0.01), showed dose-dependent increases 2 minutes after ET-3 injection (P < 0.03), and at later times remained significantly increased (P < 0.05) in contrast to flows in nondiabetic rats. CONCLUSIONS: The ET-3-induced initial rapid retinal blood flow increase in nondiabetic rats is mediated by the ET-3/ETB and NOS action. The subsequent retinal blood flow decrease is mediated by ET-3/ETA action. Diabetic rats showed comparable ET-3-induced retinal blood flow increases indicating normal ET-3/ETB action. However, at later times, retinal blood flow remained increased, suggesting an abnormal ET-3/ETA action.     

Intravitreal injection of corticosteroid attenuates leukostasis and vascular leakage in experimental diabetic retina

PURPOSE: Recently, intravitreal injection of corticosteroids has been in wide use as a treatment for diabetic macular edema, and the outcomes have been favorable. However, the exact mechanism remains unclear. The hypothesis for the current study was that intravitreal corticosteroids may improve diabetic retinal edema by amelioration of blood-retinal barrier (BRB) breakdown, by inhibiting leukocyte stasis (leukostasis). METHODS: Diabetes was induced in 6-week-old male Long-Evans rats by intraperitoneal injection of streptozotocin (75 mg/kg). Three weeks after induction of diabetes, intravitreal injection of dexamethasone (40 microg/10 microL) was performed. At 2 days after intravitreal injection, accumulated leukocytes were counted in vivo by acridine orange leukocyte fluorography, and BRB breakdown was evaluated by measurement of retinal vascular permeability. The mRNA expression and protein levels of intercellular adhesion molecule (ICAM)-1 in the retina were also studied. RESULTS: The number of leukocytes accumulated in the retina, once increased in the diabetic group, was decreased by 31.6% (P = 0.0001) after dexamethasone injection. The level of BRB breakdown, also elevated in the diabetic group, was suppressed by 61.1% (P = 0.0046) after dexamethasone injection. The level of ICAM-1 mRNA expression and its protein, upregulated in the diabetic group, were downregulated by dexamethasone treatment by 70.0% (P < 0.0001) and 56.4% (P = 0.0003). CONCLUSIONS: Intravitreal injection of corticosteroids improves diabetic retinal edema through inhibiting leukocyte recruitment in the diabetic retina.     

米诺环素对糖基化终末产物所致大鼠视网膜微血管渗漏的作用及其机制研究

目的研究基质金属蛋白酶-9（MMP-9）在糖基化终末产物（AGEs）所致血-视网膜屏障损害中的作用,评估米诺环素对AGEs所致血-视网膜屏障损害的治疗作用。方法 36只SD大鼠用随机数字表法分为牛血清白蛋白（BSA）组、AGEs-BSA组和AGEs-BSA＋米诺环素组。BSA组和AGEs-BSA组分别自尾静脉注入BSA和AGEs-BSA,每日1次,每次40mg/kg,AGEs-BSA＋米诺环素组在每日注射AGEs-BSA的同时隔日腹腔注射米诺环素45mg/kg。14d后,每组取6只大鼠用伊文思蓝（EB）法观察并比较各组视网膜血管的通透性,其余大鼠处死后,采用RT-PCR及Westernblot法观察视网膜MMP-9的表达。结果 AGEs-BSA组MMP-9mRNA和蛋白水平均较BSA组升高,差异有统计学意义（P〈0.01）,同时,视网膜微血管渗透性也显著升高（P〈0.01）。而在AGEs-BSA＋米诺环素组大鼠视网膜基因和蛋白水平的MMP-9均被抑制（P〈0.01）,同时视网膜微血管渗漏被部分逆转（P〈0.01）。视网膜微血管的渗透性与MMP-9蛋白的表达呈正相关（r=0.891,P=0.000）。结论 AGEs所致的视网膜微血管渗漏与MMP-9的高表达有密切关系,AGEs的作用至少部分是通过MMP-9实现的。米诺环素能部分逆转AGEs-MMP-9途径所致的血管渗漏。