Effects of elevated intraocular pressure on mouse retinal ganglion cells

We developed and characterized a mouse model of elevated intraocular pressure (IOP) to investigate the underlying cellular and genetic mechanisms of retinal ganglion cell (RGC) death. IOP was unilaterally increased in C57BL/6J mice by photocoagulation of the episcleral and limbal veins. IOP was measured using an indentation tonometer. RGC survival was measured by retrograde labeling using DiI applied to the superior colliculous. The mechanism of RGC death was investigated using TUNEL staining, immunostaining for cleaved caspase-3, and Western blot for Bcl-2 and Bax expression. RT-PCR was used to measure changes in Bcl-2, Bax, Bad, Bak, P53, ICE and Fas. Mean IOP was increased in the treated eyes from 13+/-1.8 to 20.0+/-2.8 mmHg at four weeks and 17+/-2.2 mmHg at eight weeks. RGC loss was 15.6+/-3.4% at two weeks and 27.3+/-4.5% at four weeks after laser photocoagulation. TUNEL staining and caspase-3 positive cells were increased in the ganglion cell layer (GCL) in the treated eyes and seldom found in the control eyes. Bcl-2 expression in control group was higher than in the experimental group, while Bax expression in the control group was less than in experimental group. This mouse model resulted in a consistent, sustained increase in IOP with a reduction in the number of RGCs in the treated eye. The RGCs in eyes with elevated IOP were TUNEL-positive, with increased caspase-3 and decreased Bcl-2, consistent with apoptosis as the mechanism of neuronal cell death.     

Neuroprotective effect of latanoprost on rat retinal ganglion cells

Background To investigate the neuroprotective effect of intravitreal administration of latanoprost on retinal ganglion cell (RGC) damage induced by N-methyl-D-aspartic acid (NMDA) or optic nerve axotomy.Methods Using Sprague-Dawley rats, retinal ganglion cell damage was induced by either intravitreal administration of NMDA or optic nerve axotomy. Latanoprost at doses of 0.03, 0.3, 3, 30 and 300 pmol was administered intravitreally before NMDA injection or optic nerve axotomy. Retinal damage was evaluated by counting the number of surviving RGCs retrogradely labeled with fluorogold under the microscope.Results Seven days after the NMDA injury, the number of surviving RGCs was significantly increased at doses of more than 30 pmol atanoprost (846±178 cells/mm² P=0.0166) compared with vehicle control (556±122 cells/mm²). Ten days after the optic nerve axotomy, the number of surviving RGC was significantly increased even at a dose of 0.3 pmol (815±239 cells/mm², P=0.0359) compared with control (462±75 cells/mm²).Conclusions Intravitreal administration of latanoprost has a neuroprotective effect on rat RGC damage induced by either NMDA or optic nerve axotomy, while its pharmacological features are different.     

O.03%贝美前列素滴眼液与0.005%拉坦前列素滴眼液的降眼压效果和安全性比较

目的比较0.03%贝美前列素滴眼液与0.005%拉坦前列素滴眼液降眼压治疗的有效性和安全性.方法随机、研究者设盲、平行对照临床试验.56例原发性开角型青光眼或高眼压症患者,随机分配接受0.03%贝美前列素和0.005%拉坦前列素治疗,观察治疗42天后降眼压效果及不良反应.结果 0.03%贝美前列素和0.005%拉坦前列素均能显著降低眼内压(P＜0.001).6周治疗后,贝美前列素和拉坦前列素降低眼压分别为5.92～9.18mmHg(26.3%～36.1%)和7.25～9.85mmHg(31.3%～38.9%),两者之间差异无统计学意义.贝美前列素和拉坦前列素均有较好的安全性,最常见的不良反应为结膜充血.结论 0.03%贝美前列素滴眼液和0.005%拉坦前列素滴眼液均能显著降低国人开角型青光眼和高眼压症患者的眼压,而且安全、有较好的耐受性.两者差异无统计学意义.     

雷公藤甲素在慢性青光眼大鼠模型中对视网膜神经节细胞的保护

背景青光眼是一种以视神经损害为病理特点的常见致盲性眼病。目前,通过延缓或阻止病程的进展而保护视神经是青光眼研究的热点。目的研究中药雷公藤的有效提取成分雷公藤甲素对慢性青光眼大鼠模型视网膜神经节细胞（RGCs）的保护作用。方法选用清洁级Wistar雌性大鼠80只,采用房水释放联合激光房角光凝法建立慢性青光眼大鼠模型。右眼为激光眼,左眼为对照眼。激光光凝前3d起每日雷公藤甲素组大鼠腹腔给予雷公藤甲素5μg／kg直至处死,生理盐水组以同样的方式给予等量生理盐水。于术前,术后1、3、5d,1周及此后每周用Tono—PenXL眼压计监测眼压。激光光凝术后1、2、4、8周制作大鼠眼球视网膜铺片并行Nissl染色,对RGCs进行定量检测。结果激光眼术后1d眼压较术前增高,术后1周达高峰,持续约3周,4周时眼压恢复正常;对照眼各时间点眼压值与术前相比差异均无统计学意义（P〉0．05）。术后各时间点雷公藤甲素组激光眼与生理盐水组激光眼间眼压的差异无统计学意义（P〉0．05）。生理盐水组激光眼术后1周RGCs数量开始减少,术后4～8周RGCs存活数量明显下降;与生理盐水组激光眼相比,各时间点雷公藤甲素组激光眼RGCs数量明显增多,差异均有统计学意义（P〈0．05）。雷公藤甲素组激光眼与其对照眼相比,各时间点RGCs数目的差异均无统计学意义（P〉0．05）。结论雷公藤甲素能防止慢性青光眼大鼠模型的RGCs损伤,对RGCs具有保护作用,该作用并不依赖于眼压的下降,这可能为青光眼的治疗提出新思路。     

Effect of epigallocatechin-gallate on inner retinal function in ocular hypertension and glaucoma: A short-term study by pattern electroretinogram

Background  Epigallocatechin-gallate (EGCG) is a powerful antioxidant with suggested neuroprotective action. The aim of this study was to evaluate the effect of short-term supplementation of EGCG on inner retinal function in ocular hypertension (OHT) and open-angle glaucoma (OAG). Methods  Eighteen OHT and 18 OAG patients (perimetric mean deviation: >−10 dB) were randomly assigned to assume oral placebo or EGCG over a 3-month period in a randomized, placebo-controlled, double-blind, cross-over design clinical trial (clinicaltrials.gov identifier: NCT00476138). Pattern-evoked electroretinograms (PERGs) to 1.6 cycles/degree square-wave gratings, counterphased at 16 reversals/second, and standard automated perimetry (Humphrey 30–2) were assessed at the study entry (baseline), and after 3 months of placebo or EGCG. Results  After EGCG, PERGs of OAG, but not OHT patients were increased in amplitude, compared either to baseline values (mean amplitude change: 0.06 log μV, p < 0.05) or to PERG amplitude values found in the same patients after placebo administration (mean change: −0.02 log μV, p not significant; difference between EGCG and placebo: 0.08 log μV, p < 0.05). In both OHT and OAG patients, standard automated perimetry did not show significant changes after either EGCG or placebo. In individual OAG patients, the magnitude of PERG amplitude increment after EGCG was inversely related (r = −0.8, p < 0.01) to corresponding baseline amplitudes. Conclusions  Although this study cannot provide evidence for long-term benefit of EGCG supplementation in OAG, and the observed effect is small, the results suggest that EGCG might favourably influence inner retinal function in eyes with early to moderately advanced glaucomatous damage. Drs Falsini and Marangoni contributed equally to this article     

Evaluation of retinal ganglion cell function after intraocular pressure reduction measured by pattern electroretinogram in patients with primary open-angle glaucoma

Background

To evaluate retinal ganglion cell (RGC) function after intraocular pressure (IOP) reduction measured by pattern electroretinogram (PERG) in patients with newly diagnosed, non-treated preperimetric and early stages of primary open-angle glaucoma (POAG).

Methods

Twenty-four eyes from 24 patients with POAG: 11 eyes with preperimetric glaucoma and 13 eyes with early glaucoma received Ganfort ^® (bimatoprost + timolol) once a day for a period of 1 month. Before and after the treatment, following measurements were analyzed: IOP, mean ocular perfusion pressure (MOPP), peak time of P50 and amplitude of P50 and N95 waves in PERG (ISCEV standard 2012). Correlations between PERG P50 and N95 waves, IOP and MOPP were calculated.

Results

After therapy, IOP significantly decreased in all eyes, on average 31%. Significant increase in MOPP in all eyes on average 14% was detected. PERG amplitude of P50 and N95 waves increased in 75 and 79% eyes, respectively, on average P50 by 28% and N95 by 38%. There were no significant interactions between the change of PERG parameters in time and stage of glaucoma.

Conclusions

Significant IOP-lowering therapy can improve RGC function measured by PERG, in patients with preperimetric and early stages of POAG.

     

腺相关病毒介导的脑源性神经营养因子对DBA／2J小鼠视网膜神经节细胞的保护作用

背景神经营养因子的缺乏与青光眼的视神经损害密切相关。外源性神经营养因子的补充具有短暂的保护作用。腺相关病毒（AAV）介导的神经营养因子可在眼内长期表达,但是否对青光眼动物的视神经具有持久的保护作用有待研究。目的评估AAV介导的脑源性神经营养因子（BDNF）基因在DBA／2J小鼠眼内的表达及其对视网膜神经节细胞（RGCs）的保护作用。方法健康清洁级DBA／2J小鼠10只从4月龄起,每月使用Tonolab眼压计测量眼压。6月龄时左眼玻璃体腔内注射AAV介导的BDNF和绿色荧光蛋白（GFP）基因（AAV—BDNF—GFP）1μ1,右眼注射等量的生理盐水作为对照。注射后3个月心脏灌流后取出视网膜,荧光显微镜下观察GFP在视网膜中的表达,免疫组织化学法计算存活的RGCs数目并进行比较。结果DBA／2J小鼠4月龄时AAV—BDNF—GFP眼眼压平均为11．90mmHg,对照眼眼压为11．40mmHg。实验眼与对照眼眼压5月龄时均开始升高,8月龄时达到高峰。从4月龄到9月龄,实验组和对照组眼压比较差异无统计学意义（t=-1．78～0．61,P=0．11—0．90）。玻璃体腔注射AAV—BDNF—GFP3月龄后视网膜可以观察到GFP阳性细胞,转染率为46．33％±8．08％。AAV—BDNF—GFP组实验眼的平均RGCs的密度为（3168．13±1319．33）mm^2,对照眼为（2024．81±796．38）mm^2,差异有统计学意义（t=2．75,P=0．02）。结论AAV介导的BDNF对DBA／2J小鼠RGCs有保护作用。     

Adaptive changes of inner retina function in response to sustained pattern stimulation

We have characterized adaptive changes of inner retina function in response to sustained pattern stimulation in 32 normal subjects with an age range 23-77 years by measuring changes of the pattern electroretinogram (PERG) as a function of time. Contrast-reversal stimuli had square-wave profile in space and time, with peak spatial and temporal frequency and high contrast to maximize response amplitude. The PERG signal was sampled over 5 min with a resolution of 15 s. PERG signals were non-stationary, resulting in either progressive amplitude decline or even enhancement to a plateau, with a time course that could be well described by an exponential function with a time constant of 1-2 min. Higher initial amplitudes were generally associated with amplitude decline, and lower initial amplitudes with enhancement. The delta amplitude (plateau minus initial) was a linear function of the initial amplitude. The magnitude of delta decreased with decreasing initial amplitude and inverted its sign for initial amplitudes about 1/3 lower than the maximum initial amplitude measured, but still about 3-4 times larger than the noise. Amplitude decline was generally associated with phase lag, whereas amplitude enhancement was associated with phase advance. Altogether, PERG generators appear to slowly adjust their gain in order to keep their sustained activity at an intermediate level that is rather independent of the level of activity at stimulus onset. This behavior is reminiscent of a buffering mechanism, where glial cells may play a primary role. An energy-budget model of neural-vascular-glial interaction is provided together with an equivalent electrical circuit that accounts for the results.     

图形视网膜电图检测原发性开角型青光眼视网膜功能的意义

目的 观察原发性开角型青光眼图形视网膜电图的改变及其特点,了解ＰＥＲＧ在检测ＰＯＡＧＰＹ视网膜功能方面的意义。方法 对３６例（５９只眼）ＰＯＡＧ及３２例（５９只眼）年龄相匹配的正常人进行ＰＥＢＧ检测。结果 ＰＯＡＧ患者ＰＥＲＧ的ＡＰ１、ＡＮ２、ＡＮ１、ＡＮ２／ＡＰ１下降;运用ＡＮ２＋ＡＰ１〈２．７及ＡＮ２／ＡＰ１下降;运用ＡＮ２＋ＡＰ１〈２．７及ＡＮ２／ＡＰ１〈０．７的方法,对已确认的ＰＯＡＧ进行     

视网膜脱离术毕眼压测定的临床观察

目的 通过对视网膜脱离术毕及术后眼压测量。探讨视网膜脱离术后眼压的变化及对预后的影响。方法 41例视网膜脱离患者术毕时在手术台及术后1-5天用Perkins压平眼压计测量眼压,每次测量眼压时连续测量两次,取平均值。结果 41只眼术毕与术后第1天及第2天眼压与健眼比较,术眼明显高于健眼。从第3-5天眼压与健眼比较,两眼眼压无显著性差异。术眼术后第1天因眼压高引起的并发症有12只眼（29.2%)。结论 视网膜脱离术毕眼压控制在2.8kPa,有利于视网膜复位。术后第1-2天有可能产生一时性的眼压增高,由此而产生的并发症很快会消失,不影响预后。     

3D-OCT对早期原发性青光眼黄斑区视网膜神经节细胞复合体及神经纤维层结构变化的评估

背景 视网膜神经纤维层(RNFL)变薄被认为是能够检测到的青光眼最早期的改变,3D-OCT对黄斑区神经节细胞复合体(mGCC)厚度的检测使得检测黄斑区节细胞的改变成为可能,为更早发现和诊断青光眼提供思路. 目的 利用3D-OCT检查系统检测早期原发性青光眼mGCC厚度及视盘周围RNFL厚度的变化,评估早期原发性青光眼视神经损害的解剖基础. 方法 对2010年12月至2012年12月在中日友好医院眼科就诊的一眼为中晚期而对侧眼为早期的原发性青光眼的10例患者采集的3D-OCT扫描图像进行回顾性分析.所有患者均符合1987年中国青光眼学组推荐的诊断标准,临床检查资料完整.患者均接受常规眼科检查和眼底3D-OCT检查,分别采用3D-macular模式、3D-macular Wide模式和3D-disc模式对原发性青光眼黄斑区、后极部和视盘进行扫描,利用检查系统自带软件对黄斑6 mm×6 mm区域的扫描结果进行分析,由黄斑中心凹向外各方向等距离分成100个小格区,每个格区面积为0.6 mm×0.6 mm,按照mGCC的变薄程度由重到轻依次以红色、黄色和灰色标记,以每个小格中的数字与其正常值比较得到与颜色匹配的、mGCC变薄程度发生的概率值(依次为P＜1％、P＜5％、P≥5％)表示.然后分析视盘旁RNFL厚度和不同部位的厚度曲线改变,并评估视盘生理凹陷的改变. 结果 10例患者患早期青光眼的眼和对侧眼视细胞层和双极细胞层厚度均未发生改变,而患中晚期青光眼的一侧眼视盘周围RNFL厚度概率图呈红色,即视盘周围RNFL层厚度明显变薄,mGCC厚度概率和黄斑区RNFL厚度概率图呈红色,即mGCC和黄斑区RNFL层厚度明显变薄;而患早期青光眼的一侧眼视野均正常,mGCC厚度概率图和黄斑区RNFL区呈黄色,即mGCC和黄斑区RNFL厚度轻微变薄;视盘周围RNFL厚度概率图呈绿色或黄色,即视盘周围RNFL厚度正常或轻微变薄.结论 原发性青光眼mGCC层厚度变薄早于视盘周围RNFL的变薄,提示青光眼视神经结构的损害始于RGCs的细胞体并早于轴突的损伤或丢失.     

Circadian changes of intraocular pressure and ocular perfusion pressure after timolol or latanoprost in Caucasians with normal-tension glaucoma

Purpose To evaluate the circadian effects on intraocular pressure (IOP) and ocular perfusion pressure (OPP) of 0.5% timolol or 0.005% latanoprost in Caucasian patients affected by normal-tension glaucoma (NTG). Patients and methods In this crossover trial, 30 consecutive NTG subjects underwent three 24-hour assessments of IOP, blood pressure (BP), heart rate (HR), and OPP [calculated according to the formula OPP = (1/3 systolic BP + 2/3 diastolic BP) x 2/3 – IOP]: at baseline, and after 1-month treatment with timolol or latanoprost. These parameters were recorded at 4 a.m., 8 a.m., noon, 4 p.m., 8 p.m., and midnight. Results Both timolol and latanoprost reduced IOP (p < 0.001), with a difference in favour of latanoprost of 1.3 mmHg (95% CI 0.9, 1.6; p < 0.001). After timolol, BP and HR decreased with respect to baseline (p < 0.001). Latanoprost increased mean OPP (3.6 mmHg, 95% CI 2.9, 4.3; p < 0.001), whereas timolol did not improve it. Conclusions Latanoprost induces an IOP reduction greater than timolol, also achieving a better circadian flattening of the IOP curve. Only latanoprost significantly increased mean 24-hour OPP. The management of Caucasian NTG patients should be critically realized, considering the 24-hour influence of each IOP-lowering drug on the ocular blood perfusion.     

Neuroprotective effects of prostaglandin analogues on retinal ganglion cell death independent of intraocular pressure reduction

Prostaglandin (PG) analogues may have an additional effect to protect neurons independent of IOP reduction. Only a few reports indicated that some PG analogues had neuroprotective effects or increased blood flow in in vivo and in vitro models. However, there is no comparative study using all clinically available PG analogues and also using primary culture of retinal ganglion cell (RGC). Our purpose of study is to investigate the direct neuroprotective effect of PG analogues on glutamate- and hypoxia-induced RGC death using rat purified primary RGC culture with latanoprost acid, travoprost acid, bimatoprost acid, bimatoprost, tafluprost acid, unoprostone, and PGF2α. Purified RGCs cultures were obtained from retinas of 6 days old Wistar rats, following a two-step immuno-panning procedure. After 72 h of cultivation, the neuroprotective effect of PG analogues (1 nM, 10 nM and 100 nM) was investigated by culturing the RGCs in 25 μM glutamate for a further 72 h or 5% O2 hypoxic condition for 24 h. The RGC viability under each condition normalized to that under normal condition without stress was evaluated as live cell percentage based on a total of 15 repeated experiments. As a result, 100 nM of latanoprost acid, tafluprost acid, bimatoprost acid, and bimatoprost significantly increased RGC survival rate by suppressing apoptosis. PG analogues indicated IOP independent neuroprotective effect on glutamate- or hypoxia-induced RGC death using rat primary RGC culture at clinically available intracameral concentration. Since those profiles were different from clinical efficacy in IOP reduction, the mechanism of neuroprotection may be not related to FP receptor stimulation.     

Age and intraocular pressure in murine experimental glaucoma

Age and intraocular pressure (IOP) are the two most important risk factors for the development and progression of open-angle glaucoma. While IOP is commonly considered in models of experimental glaucoma (EG), most studies use juvenile or adult animals and seldom older animals which are representative of the human disease. This paper provides a concise review of how retinal ganglion cell (RGC) loss, the hallmark of glaucoma, can be evaluated in EG with a special emphasis on serial in vivo imaging, a parallel approach used in clinical practice. It appraises the suitability of EG models for the purpose of in vivo imaging and argues for the use of models that provide a sustained elevation of IOP, without compromise of the ocular media. In a study with parallel cohorts of adult (3-month-old, equivalent to 20 human years) and old (2-year-old, equivalent to 70 human years) mice, we compare the effects of elevated IOP on serial ganglion cell complex thickness and individual RGC dendritic morphology changes obtained in vivo. We also evaluate how age modulates the impact of elevated IOP on RGC somal and axonal density in histological analysis as well the density of melanopsin RGCs. We discuss the challenges of using old animals and emphasize the potential of single RGC imaging for understanding the pathobiology of RGC loss and evaluating new therapeutic avenues.     

法舒地尔对大鼠急性高眼压视网膜神经节细胞的保护作用及其机制

目的 观察法舒地尔对大鼠急性高眼压视网膜神经节细胞(RGCs)的保护作用并探讨其机制.方法 实验研究.24只SD大鼠被随机分入正常组(N组)、模型组(M组)、模型+磷酸缓冲液组(MP组)、模型+法舒地尔组(F组),正常组不做任何处理,后三组制作急性高眼压模型(生理盐水灌注法).其中MP组和F组于造模前1周、当天及其后每天分别腹腔注射磷酸缓冲液(PBS) 25 mg/kg和法舒地尔25 mg/kg,各组于造模后7 d取眼球和心脏血,采用TUNEL法测定RGCs凋亡指数(AI)反映RGCs凋亡情况,免疫组化法观察各组视网膜中Rho激酶-2(ROCK-2)和内皮素(ET-1)的分布,并用吸光度值(OD)反映各自表达量;采用Western blotting法测定各组视网膜中磷酸化的肌球蛋白磷酸酶靶单位(p-MYPT-1)的表达,放射免疫法测定血浆中ET-1含量,血液流变仪测量不同剪变率下的全血黏度、红细胞聚集指数(BCAI)和红细胞压积(HCT).各指标组间比较采用单因素方差分析,两两比较采用LSD-t检验.结果 各组RGCs AI差异具有统计学意义(F=402.041,P=0.000),其中F组RGCs AI为33.3%±2.0%,少于M组(64.3%±2.2%)或MP组(62.5%±2.2%)(P<0.05).N组视网膜的节细胞层(GCL)中仅散在几个ROCK-2和ET-1阳性细胞,M、MP和F组ROCK-2阳性细胞分布于GCL、内丛状层(IPL)、内核层(INL)、外丛状层(OPL)和外核层(ONL)中,而ET-1阳性细胞分布于前4层,ONL中无表达,且两者在M和MP组中的OD值高于N组(N、M及MP组ROCK-2:0.21±0.03、0.52±0.06、0.54±0.03;ET-1:0.22±0.05、0.51±0.03、0.51±0.04)(P均<0.01),F组OD值(ROCK-2:0.37±0.04;ET-1:0.35±0.06)低于M或MP组(P均<0.05),但仍高于N组(P均<0.05).ROCK-2和ET-1在各组表达差异具有统计学意义(F=82.862、56.491,P=0.000).Western blotting检测发现各组视网膜中P-MYPT-1表达差异具有统计学意义(F=606.236,P=0.000),M和MP组表达量分别为0.522±0.013和0.520±0.013,高于N组(0.263±0.014)(P<0.01),F组表达量(0.302±0.015)低于M或MP组(P<0.05),但仍高于N组(P<0.05).放射免疫法检测发现各组血浆ET-1含量差异有统计学意义(F=8.750,P=0.000),M和MP组含量均为(96±10)pg/ml,高于N组[(72±10)pg/ml](P<0.05),F组含量为(78+10)pg/ml,低于M或MP组(P<0.05),但仍高于N组(P<0.05).血液流变仪检测发现各组低切、中切、高切状态下全血黏度,BCAI和HCT差异有统计学意义(F=7.086、4.279、14.780、37.351、143.264,P均<0.05),且各指标中M或MP组较N组高(P<0.05),F组较M或MP组低(P<0.05),但仍高于N组(P<0.05).结论 法舒地尔可以抑制大鼠急性高眼压模型中RGCs的凋亡,对RGCs有保护作用,推测其机制可能与抑制ROCK-2、减少p-MYPT-1、减少肌动蛋白-肌球蛋白交联、抑制平滑肌收缩、减少缩血管因子ET-1表达、降低血黏度有关.     

七氟烷吸入麻醉对大鼠青光眼造模眼眼压的影响

目的研究吸入麻醉药七氟烷对磁性微球前房注射诱导实验性大鼠青光眼造模眼和正常眼眼压(IOP)的影响。方法雄性8～10周挪威褐鼠6只,进行2周清醒状态下IOP测量训练后,采用磁性微球前房注射方法诱导实验性青光眼,右眼为青光眼造模眼,左眼为自身对照眼,研究吸入麻醉药七氟烷麻醉对造模眼和对照眼IOP的影响。结果七氟烷可明显降低造模眼和对照眼的IOP,麻醉平稳后造模眼IOP最大降低幅度为52.6%(t=20.61),对照眼最大降低幅度为37.5%(t=4.98),造模眼降低的程度明显大于对照眼。造模眼IOP在大鼠苏醒后仍低于基础值,差异有统计学意义,而对照眼IOP在苏醒后即恢复至接近基础值。结论七氟烷吸入麻醉可以显著降低大鼠IOP,其中青光眼造模眼的下降幅度更为显著,持续时间更长。该结果提示在对先天性青光眼患儿使用七氟烷全身麻醉下检查时,应充分考虑到该药物降低IOP的作用。     

大鼠高眼压模型中热休克蛋白27抗体及视网膜神经节细胞凋亡的研究

背景 青光眼是一组以视网膜神经节细胞( RGCs)慢性丢失为特征的常见致盲性眼病.目前青光眼的发病机制尚不完全清楚,热休克蛋白27 (HSP27)抗体可能与青光眼视神经病变有关系. 目的 通过建立大鼠高眼压模型,检测血清中HSP27抗体的表达及RGCs的凋亡,了解HSP27抗体与眼压及RGCs凋亡的关系.方法 将51只Wistar大鼠按随机数字表法随机分为高眼压组34只和伪手术对照组17只,均取右眼为实验眼,左眼为对照眼.采用双极水下电凝器电凝高眼压组大鼠右眼巩膜表面3组静脉,建立高眼压动物模型.伪手术对照组大鼠右眼只剪开上方球结膜,不做电凝.分别于术后1、2、4、6、8周处死高眼压组大鼠6、6、6、8、8只,伪手术对照组大鼠3、3、3、4、4只.处死前测大鼠双眼眼压,并收集血清1 ml测定大鼠血清HSP27抗体.10只大鼠(2个组各时间点各1只)实验眼剥离视网膜,经匀浆后提取视网膜蛋白质用于Western blot分析.摘除剩余41只大鼠双侧眼球,制作石蜡切片.TUNEL法检测视网膜组织切片中RGCs的凋亡情况.结果 大鼠造模后3d,1、2、4、6、8周实验眼眼压较术前均明显增高,各时间点的总体比较差异有统计学意义( F=318.502,P＜0.01),但伪手术对照组手术前后眼压变化差异无统计学意义(F=2.076,P＞0.05).高眼压组大鼠实验眼视网膜HSP27蛋白水平与伪手术对照组大鼠实验眼比较均有升高.高眼压组大鼠术后1、2、4、6、8周血清中HSP27抗体各时间点总体比较差异有统计学意义(F=154.221,P＜0.01),随着造模时间的延长,血清HSP27抗体呈逐渐升高的趋势,而伪手术对照组手术前后HSP27抗体的变化差异无统计学意义( F=0.422,P＞0.05).高眼压组造模后实验眼不同时间点RGCs凋亡阳性细胞率比较差异有统计学意义(x2=856.12,P＜0.05).高眼压组不同时间点RGCs凋亡阳性细胞率均较伪手术对照组高(P＜0.05).结论 随着眼压的升高以及高眼压持续时间的延长,大鼠血清中的HSP27抗体水平逐渐升高,视网膜在高眼压状态下HSP27表达上调.逐渐升高的HSP27抗体水平与RGCs凋亡增加的趋势一致.     

Development of inner retinal function, evidenced by the pattern electroretinogram, in the rat

Though the rat is increasingly used as an animal model in ophthalmic research, including the study of glaucoma, little is known about age-related changes in its inner retinal function. The aim of this study was to evaluate these changes in the rat during the first 18 weeks of life. The pattern electroretinogram (PERG) was used to monitor inner retinal activity in 16 developing rats. In each animal, recordings were conducted at ages 3, 5, 7, 11, 14 and 18 weeks to assess age-related changes in function. Signals were evoked by five stimuli of progressively increasing check width (subtending 82-1312 arc minutes of visual angle) that were projected directly onto the fundus through a specially modified ophthalmoscope which allowed visual and manual control of stimulus quality. Poor signal:noise ratio prevented signal analysis at age 3 weeks. Subsequently, PERG amplitude increased significantly, up to 242% (depending on stimulus check width), during weeks 5-11. After peaking at 11 weeks, signal amplitude declined moderately. Signal latency mirrored that of amplitude, decreasing during the first 11 weeks, and then increasing steadily. Latency was not affected by stimulus check width. Age was highly correlated with P1 latency (R(2)=0.80) and moderately correlated with N2 latency (R(2)=0.52). Therefore, we propose that studies of inner retinal diseases (such as glaucoma) in the rat model should use age-matched controls, as electrophysiological results may be confounded by age-related changes. The rat PERG undergoes many of the age-related changes that have been reported in humans, and thus may serve as an animal model to study development of inner retinal function.     

Characterization of intraocular pressure pattern and changes of retinal ganglion cells in DBA2J glaucoma mice

AIM: To characterize the pattern of intraocular pressure (IOP) change and the deficit of retinal ganglion cells (RGCs) in DBA2J, which is most wellcharacterized chronic glaucoma mouse model and wild type (WT) C57bl/6 mice, and to study the relationship between IOP change and RGCs deficit. METHODS: IOP was monitored with a rebound tonometer in WT C57bl/6 and DBA2J mice from 3 to 15-monthold. Retinal function was evaluated by dark-adapted electroretinogram (ERG) in DBA2J and WT mice of 15monthold. A dye (Neurobiotin) was applied to optic nerve stump to retrograde label RGCs. TO-PRO-3 visualized all nuclei of cells in the RGC layer. RESULTS: The IOP in WT mice was 9.03±0.6 mm Hg on average and did not increase significantly as aging. The IOP in DBA2J mice, arranging from 7.2 to 28 mm Hg, was increasing significantly as aging, and it was normal at 3monthold compared with WT mice, slightly increased from 7-monthold and increased in 50% animals at 11monthold and in 38% animals at 15-monthold. The RGCs density in DBA2J mice started reducing by 7month-old, continuously decreased until reached about 20% of RGC in WT retina by 15monthold. RGC density was not linearly correlated with IOP in 15-monthold DBA2J mice. The amplitude of positive scotopic threshold response, and negative scotopic threshold response of ERG were significantly reduced in DBA2J mice of 15-monthold than that in agepaired WT mice. CONCLUSION: The present study found that DBA2J mice display pathological and functional deficits of the retina that was not linearly correlated with IOP.     

醋甲唑胺降低兔眼内压的研究

目的 探讨醋甲唑胺对青光眼的治疗价值。方法 对３０只成年家兔随机分为５组,实验组口服不同剂量的醋甲唑胺,观察其对急性高眼压模型的影响及对低眼压恢复模型的影响。结果 １０ｍｇ／ｋｇ体重以上剂量的醋甲唑胺对兔急性高眼压均具有显著的降眼压作用,且能显著延缓低眼压的恢复。同时可见随给药剂量的增加,降眼压作用及延缓低眼压恢复的作用增强,呈量效关系。结论 醋甲唑胺可作为一种新的抗青光眼药应用于临床。