Rhythmicity in rabbit retinal ganglion cell responses

An interesting pattern of rhythmic spike bursts was observed in the light responses of rabbit retinal ganglion cells when using a fast time scale. This rhythmicity was found in all ganglion cell types tested in all parts of the retina. The presence and extent of rhythmicity was related to the intensity, size and shape of the light stimulus. The best stimulus extended into the receptive field surround yet still evoked a strong response from the center. We suggest that rhythmicity results from time delays in the inhibitory interactions between central and surround pathways to the ganglion cells.     

Experimental detection of retinal ganglion cell damage in vivo

In vivo detection of retinal ganglion cell (RGC) damage should have experimental and clinical relevance. A number of experimental models have been recently described to visualize RGCs in vivo. With retrograde injection of fluorescent tracers into the superior colliculus, lateral geniculate body, or optic nerve, RGCs can be detected in vivo with confocal laser scanning microscopy, fluorescent microscopy, or confocal scanning laser ophthalmoscopy. Although the resolution of these imaging techniques is limited to detecting only the cell bodies, the addition of adaptive optics has allowed in vivo visualization of axonal and dendritic processes. An ideal experimental model for detection of RGC damage should be non-invasive and reproducible. The introduction of a strain of transgenic mice that express fluorescent proteins under the control of Thy-1 promoter sequence has offered a non-invasive approach to detect RGCs. Long- term serial monitoring of RGCs over a year has been shown possible with this technique. In vivo imaging of RGCs could provide crucial information to investigating the mechanisms of neurodegenerative diseases and evaluating the treatment response of neuroprotective agents.     

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.     

睫状神经营养因子对培养大鼠视网膜神经节细胞的影响

目的 观察不同浓度睫状神经营养因子(ciliary neurotrophic factor，CNTF)对培养大鼠视网膜神经节细胞（retinal ganglion cell，RGC）生长、存活的影响。 方法 取15只生后2～3d Wistar大鼠视网膜组织进行细胞培养，通过Thy-1单克隆抗体免疫细胞化学对培养的RGC进行鉴定。实验分对照组和10、20、40 ng/mlCNTF组（Ⅰ、Ⅱ、Ⅲ组），记录RGC存活时间，将培养第3、5、7天的RGC行四甲基偶氮唑盐（methylthio tetrazole,MTT）法测量吸光度(A)值［旧称光密度(OD)］。 结果 Thy-1单克隆抗体免疫组织化学检查显示培养3d的存活细胞90%以上为RGC。细胞存活期间实验组与对照组细胞均无明显突起,细胞体积无明显增大，实验组细胞存活时间比对照组长3~4d。培养第5、7d，Ⅰ组A值分别为0.075 8±0.0139、0.0693±0.0113，Ⅱ组A值分别为0.0902±0.0114、0.0825±0.0125，Ⅲ组A值分别为0.0792±0.0133、0.0653±0.0086，对照组A值分别为0.0620±0.0071、0.0513±0.0068。实验组与同时间对照组A值相比差异有显著性的意义（Ⅱ组与对照组相比P＜0.01，Ⅰ、Ⅲ组与对照组相比P＜0.05）。 结论 一定浓度的CNTF能促进培养大鼠RGC的存活，对RGC形态无影响。 (中华眼底病杂志, 2002, 18: 283-285)     

视网膜神经节细胞凋亡的信号通路研究进展

视网膜神经节细胞（RGCs）的进行性凋亡是许多视网膜病变和视神经疾病进展到最后的必经之路,是多种眼病致盲的根本原因.RGCs对外界因素的影响异常敏感,外伤、高眼压、炎症和神经毒素等均可造成其不可逆的损伤,而这些细胞外信号又通过不同的途径影响着细胞内部的信号转导,调节细胞内凋亡相关基因的表达,最终造成RGCs的凋亡.本文从细胞外部因素的诱导、细胞内部的信号传递和基因调控3个方面总结病理情况下RGCs凋亡信号转导通路研究的最新进展,旨在为视网膜神经保护药物的开发提供新的思路.     

Functional transmitters at retinal ganglion cells in the cat

The effects of iontophoretically applied putative neurotransmitters and their antagonists on the responses of retinal ganglion cells were studied in the optically intact eye of anaesthetized cats. L-aspartate enhanced and a N-methyl-D-aspartate receptor blocker, 2-amino-5-phosphonovalerate, blocked visual excitations of "sustained" cells, whereas acetylcholine enhanced, and the nicotinic receptor blocker, dihydro-beta-erythroidine, blocked those of "transient" cells. GABA enhanced and bicuculline blocked inhibitions of on-centre cells, but glycine enhanced and strychnine blocked those of off-centre cells, whether the cells were "sustained" or "transient". The possibility that: (A) aspartate may be an excitatory transmitter at both "on-" and "off-sustained" cells and acetylcholine, at both "on-" and "off-transient" cells; (B) GABA may be an inhibitory transmitter for on-centre, and glycine, for off-centre cells, is discussed.     

小鼠视网膜神经节细胞的纯化培养

目的 建立小鼠视网膜神经节细胞的体外纯化培养方法。方法 实验研究。采用Thy-1.2单克隆抗体免疫吸附法,将8～ 12只生后4～6d的C57BL/6小鼠视网膜消化后,制成视网膜神经细胞混合悬液,应用胶质细胞特异性抗体CD11b室温孵育后,去除混悬液中的胶质细胞,应用特异性抗体Thy-1.2吸附混合悬液中的视网膜神经节细...     

N-甲基-D-天门冬氨酸对大鼠视网膜神经节细胞层神经元的损伤作用

目的 探讨N—甲基—D—天冬氨酸(NMDA)对大鼠视网膜神经节细胞层(RGCL)神经元的毒性作用。方法 通过大鼠玻璃体内注入不同浓度的NMDA，观察注射前后不同时间视网膜神经节细胞层的神经元计数。结果 大鼠RGCL神经元计数随NMDA浓度增加及时间延长而逐渐减少。其中以大神经元对NMDA兴奋毒性最敏感。结论 NMDA可导致RGCL神经元损伤，并显示以大神经元最先受损，即与青光跟性视神经损伤相似，此模型可应用于研究青光跟性视神经损伤机制。     

促红细胞生成素缓释微球玻璃体腔注射对视网膜神经节细胞的保护作用

目的 探讨乳酸/羟基乙酸共聚物（PLGA）装载的促红细胞生成素（EPO）缓释微球（EPO-PLGA微球）经玻璃体腔注射对大鼠视神经挫伤模型中受损视网膜神经节细胞（RGC）的保护作用.方法 选取成年SD大鼠,建立视神经挫伤模型.建模后分别经玻璃体腔内注射含10 IU EPO的PLGA微球（EPO-PLGA组）、10 IU EPO（EPO组）、5 μl空白PLGA（PLGA组）、5 μl PBS（PBS组）,另设未治疗组不予玻璃体腔注药.术后5 d和2周,做视网膜切片,对各组RGC凋亡情况行TUNEL检测;术后23 d,DiI上丘逆标RGC,并于术后4周处死大鼠,视网膜铺片观察各组RGC存活情况;每组各个时间点分别处死6只SD大鼠.采用方差分析对结果进行比较.结果 TUNEL检测显示,术后5 d和2周,各组均可见TUNEL阳性细胞,其中EPO-PLGA组和EPO组TUNEL阳性细胞显著减少,其细胞凋亡率明显少于PLGA组、PBS组及未治疗组.术后4周,视网膜铺片RGC计数显示,正常SD大鼠RGC密度为（2387.7±164.9）个/mm^2,未治疗组为（748.3±58.8）个/mm^2,EPO-PLGA组为（1296.7±157.6）个/mm^2,EPO组为（1418.5±154.9）个/mm^2,PLGA组为（821.7±52.1）个/mm^2,PBS组为（804.4±86.4）个/mm^2;可见EPO-PLGA组和EPO组较未治疗组细胞密度显著增高,具有明显的RGC保护作用（P均＜0.01）,而EPO-PLGA组和EPO组间差异无统计学意义（P=0.065）.结论 EPO-PLGA缓释微球与EPO具有等效的RGC保护作用,这为进一步观察EPO-PLGA缓释微球的长效神经保护作用奠定了基础.     

The neuropeptide NAP provides neuroprotection against retinal ganglion cell damage after retinal ischemia and optic nerve crush

Background  NAP, an 8-amino acid peptide (NAPVSIPQ=Asn-Ala-Pro-Val-Ser-Ile-Pro-Gln) derived from activity-dependent neuroprotective protein (ADNP), plays an important role in neuronal differentiation and the survival of neurons in different pathological situations. We already discovered that NAP increases the survival of retinal ganglion cells (RGC) in vitro, and supports neurite outgrowth in retinal explants at femtomolar concentrations. The aim of this study was to investigate the effects of NAP on RGC survival after transient retinal ischemia and optic nerve crush. Methods  RGC of male Wistar rats were labelled retrogradely with 6 l FluoroGold injected stereotactically into both superior colliculi. Seven days later, retinal ischemia was induced by elevating the intraocular pressure to 120 mm Hg for 60 minutes or by crushing one optic nerve for 10 s after a partial orbitotomy. NAP was either injected intraperitoneally in the concentration of 100 mg/kg 1 day before, directly after, and on the first and the second days after damage, or intravitreally (0.05 or 0.5 μg/eye) directly after the optic nerve crush. Controls received the same concentrations of a control peptide. Densities of surviving RGC and activated microglial cells (AMC) were quantified in a masked fashion 10 days after damage by counting FluoroGold-labelled cells. Results  After retinal ischemia, intraperitoneal injections of NAP increased the number of surviving RGC by 40% (p < 0.005) compared to the control group. After optic nerve crush, NAP raised the number of surviving RGC by 31% (p = 0.07) when injected intraperitoneally and by 54% (p < 0.05) when administered intravitreally. Conclusions  NAP acts neuroprotectively in vivo after retinal ischemia and optic nerve crush, and may have potential in treating optic nerve diseases. Supported by the Ernst und Berta Grimmke Stiftung, Germany. IG is the incumbent of the Lily and Avraham Gildor Chair for the Investigation of Growth Factors and the Director of the Adams Super Center for Brain Research at Tel Aviv University and is the Chief Scientific Officer of Allon Therapeutics Inc., Vancouver, Canada. An erratum to this article can be found at     

黄芪多糖对急性高眼压诱导大鼠视网膜神经节细胞的保护作用

背景青光眼患者视神经保护的问题日益引起关注。黄芪多糖（APS）是黄芪的主要活性成分,可增加再生神经蛋白的表达并促进损伤的周围神经修复,但其对视网膜神经节细胞（RGCs）再生作用的研究少见报道。目的探讨APS对急性高眼压状态下RGCs的保护作用。方法采用抽签法将40只SPF级sD大鼠随机分为正常对照组、模型对照组、低剂量APS组和高剂量APS组,每组各10只。低剂量APS组和高剂量APS组大鼠自实验开始每日分别给予APS500mg／kg、2000mg／kg（均溶于2．5ml生理盐水）灌胃,模型对照组仅给予2．5ml生理盐水灌胃,正常对照组不做任何处理。用药2周后,除正常对照组外,其余3个组均抽取0．2ml房水继而单眼前房注射等体积甲基纤维素使眼压升高至22mmHg（1mmHg=0．133kPa）以上制作急性高眼压模型。造模后5d,过量麻醉法处死动物,摘除该眼球制作视网膜石蜡切片,常规组织病理学观察视网膜的形态结构变化,采用免疫组织化学法检测caspase-3蛋白在大鼠视网膜中的表达,采用TUNEL染色法观察和计算各组大鼠RGCs的凋亡率。ImageProPlus5．1软件测量各组大鼠视网膜厚度和神经纤维层厚度。结果大鼠成模后5d,模型对照组、低剂量APS组和高剂量APS组大鼠的眼压均明显高于正常对照组,差异均有统计学意义（t=-8．900、-10．700、-11．300,P〈0．01）。正常对照组大鼠视网膜形态正常;模型对照组大鼠视网膜水肿,细胞排列紊乱;低剂量APS组视网膜可见空泡样变性,但视网膜细胞排列较模型对照组整齐,视网膜水肿减轻;高剂量APS组视网膜水肿较明显。低剂量APS组视网膜厚度、外颗粒层及视神经纤维层厚度值均明显低于模型对照组,差异均有统计学意义（t=-23．700、-14．770、-11．640,P〈0．01）,但高剂量APS组外颗粒层及视神经纤维层厚度与模型对照组比较差异均无统计学意义（t=-0．780、-0．460,P〉0．05）。低剂量APS组大鼠caspase-3蛋白阳性RGCs百分比及RGCs凋亡百分率均明显低于模型对照组（caspase-3蛋白：F=87．710,P=0．001;RGCs凋亡：F=272．840,P〈0．01）,差异均有统计学意义（t=-11．700、-8．600,P〈0．01）,高剂量APS组与模型对照组比较caspase-3蛋白阳性RGCs百分比及RGCs凋亡百分率的差异均有统计学意义（t=-7．900、-6．400,P〈0．05）。结论500mg／kgAPS可有效抑制急性高眼压模型大鼠的视网膜水肿及RGCs的凋亡率,对急性高眼压大鼠的RGCs有保护作用。     

Cortisol promotes survival and regeneration of axotomised retinal ganglion cells and enhances effects of aurintricarboxylic acid

Background Neuroprotection is essential for repair processes after a traumatic insult in the central nervous system. We have demonstrated previously significant neuroprotective properties of the anti-apoptotic drug aurintricarboxylic acid in the model of axotomised retinal ganglion cells. Glucocorticoids are widely used to treat injuries of the nervous system. Due to the anti-inflammatory and microglia-inhibiting properties of glucocorticoids, we studied the neuroprotective effects of intravitreally administered cortisol after an optic nerve cut. Methods Ninety-eight adult Sprague–Dawley rats were used in this study. The optic nerve was cut intra-orbitally. Either vehicle or compound solution was injected intravitreally. Fluorescent dye was put onto the optic nerve stump to label retinal ganglion cells retrogradely. Retinal whole mounts were prepared 2 weeks after axotomy, and surviving retinal ganglion cells were counted. Results Two weeks after axotomy, up to 50±7% of all retinal ganglion cells survived if cortisol was injected into the eye compared with 17±5% survival if only vehicle solution was injected. The neuroprotective effects of aurintricarboxylic acid (43±5% survival) could be further enhanced if combined with cortisol (up to 61±5% survival). Regeneration of cut retinal ganglion cell axons into a peripheral nerve graft could also be enhanced by an intravitreal injection of cortisol (169±42 regenerating retinal ganglion cells per mm² vs. 73±12 cells per mm² after vehicle injection). The increase was not as high as with aurintricarboxylic acid (192±40 cells per mm²), although more retinal ganglion cells survived with cortisol. This indicates that neuronal survival alone is not sufficient for subsequent axonal regeneration. Nevertheless, regeneration could be markedly increased if aurintricarboxylic acid and cortisol were combined (308±72 cells per mm²). Conclusions Whereas aurintricarboxylic acid seems to act directly on lesioned retinal ganglion cells, cortisol seems to act on the glial environment, as indicated by microglial cell morphology and enhanced glial fibrillary acidic protein expression. The results show that both neuroprotection and regeneration can be enhanced by the combination of two simple compounds acting on different sites.     

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.     

视神经鞘切开减压术对大鼠视神经挤压伤后RGC凋亡的影响

目地观察早期视神经鞘切开减压术对大鼠视神经挤压伤后RGC凋亡的相关机制。方法大鼠91只分为对照组、损伤组、手术组各7、42、42只通过视网膜切片技术,HE染色,免疫组化SP法于伤后3、7、15各时问点视网膜神经节细胞计数及检测BCL-2和BAX阳性细胞数。结果手术组各时间点RGC计数均高于损伤组,差异有显著性（P〈0．05）。手术组各时间点BCL-2阳性细胞数均高于损伤组,BAX阳性细胞数均低于损伤组,差异有显著性（P〈0．05）。结论早期视神经鞘切开减压术可对大鼠视神经挤压伤后能上调BCL-2基因的表达和下调BAX基因的表达而抑制RGC的凋亡。     

一种稳定标记小鼠视网膜内两种不同类型神经节细胞的方法

目的 报道一种简单高效显示小鼠视网膜中两种不同类型神经节细胞的方法.方法 利用特殊标记物Brn3a和Melanopsin,通过视网膜铺片免疫荧光双标染色结合激光共聚焦显微镜,分别标记小鼠视网膜中普通视网膜神经节细胞和内在光敏视网膜神经节细胞.结果 免疫荧光染色结果表明,内在光敏视网膜神经节细胞与普通视网膜神经节细胞均位于视网膜节细胞层,相间互补分布.内在光敏视网膜神经节细胞数量较少,为普通视网膜神经节细胞的1％ ～2％,其轴突朝向视神经盘方向汇集,树突野较大,伸向内网层.结论 免疫荧光双标染色是小鼠视网膜内两种不同类型视网膜神经节细胞简单易行、稳定高效的标记方法.     

Imaging retinal ganglion cells: Enabling experimental technology for clinical application

Recent advances in clinical ophthalmic imaging have enhanced patient care. However, the ability to differentiate retinal neurons, such as retinal ganglion cells (RGCs), would advance many areas within ophthalmology, including the screening and monitoring of glaucoma and other optic neuropathies. Imaging at the single cell level would take diagnostics to the next level. Experimental methods have provided techniques and insight into imaging RGCs, however no method has yet to be translated to clinical application. This review provides an overview of the importance of non-invasive imaging of RGCs and the clinically relevant capabilities. In addition, we report on experimental data from wild-type mice that received an in vivo intravitreal injection of a neuronal tracer that labelled RGCs, which in turn were monitored for up to 100 days post-injection with confocal scanning laser ophthalmoscopy. We were able to demonstrate efficient and consistent RGC labelling with this delivery method and discuss the issue of cell specificity. This type of experimental work is important in progressing towards clinically applicable methods for monitoring loss of RGCs in glaucoma and other optic neuropathies. We discuss the challenges to translating these findings to clinical application and how this method of tracking RGCs in vivo could provide valuable structural and functional information to clinicians.     

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.     

睫状神经营养因子对大鼠急性高眼压眼视网膜神经节细胞的保护作用

背景 青光眼可以引起视网膜神经节细胞(RGCs)凋亡,据报道睫状神经营养因子(CNTF)对外伤性视神经损伤有修复作用,其是否对青光眼视神经病变有保护作用尚少见报道. 目的 观察CNTF对大鼠急性高眼压眼RGCs的保护作用.方法 24只Wistar大鼠双眼采用眼前房平衡盐液加压灌注法建立大鼠急性高眼压模型,造模前2d左眼玻璃体内注入0.5μg CNTF 5μl,右眼以同样的方法注射磷酸钠溶液5μl,另取3只正常大鼠作为正常对照.造模后1、3、7、14 d过量麻醉法处死动物并摘除眼球,制备视网膜组织学切片后采用苏木精-伊红染色法进行形态学观察,光学显微镜下计数RGCs数目;采用免疫组织化学染色法观察RGCs层谷氨酸的表达情况.结果 正常对照组大鼠视网膜各层排列整齐,细胞边界清晰;模型对照组大鼠RGCs细胞膜、细胞核均发现异常改变,有细胞空泡样变;CNTF治疗组大鼠造模后变性的RGCs数量少.与模型对照组比较,造模后3、7、14 d CNTF治疗组RGCs数目明显增加,差异均有统计学意义(均P=0.000).免疫组织化学染色表明,造模后3～7d,CNTF治疗组RGCs层谷氨酸阳性细胞数分别为(5.50±1.04)个／3个高倍视野和(6.00±1.41) 个/3个高倍视野,明显低于模型对照组的(9.00±2.91)个／3个高倍视野和(10.83±1.94)个／3个高倍视野,差异均有统计学意义(均P=0.000),而造模后1d和14 d两组间谷氨酸阳性细胞数的差异均无统计学意义(P=0.578、0.180).结论 CNTF能够下调急性高眼压眼谷氨酸在RGCs中的表达,从而对RGCs提供保护作用.     

神经生长因子对脱髓鞘性视神经炎小鼠视网膜神经组织保护作用的实验研究

目的 研究神经生长因子（NGF）对脱髓鞘性视神经炎小鼠视网膜神经组织的保护作用.方法 实验研究.50只C57BL/6小鼠按随机数字表法分为对照组（10只）、BSS组（20只）和NGF组（20只）,取右眼为实验眼.后两组应用MOG35-55多肽加完全弗氏佐剂皮下注射建立实验性视神经炎小鼠模型,每天对各组小鼠进行称重及神经功能评分.NGF组和BSS组分别于免疫后的第4天和第10天,对右眼进行玻璃体腔注射3μg/μl NGF或2 μl BSS.分别于免疫当天、免疫后的第7天和免疫后的第14天,对每组小鼠进行闪光视觉诱发电位（f-VEP）和闪光视网膜电图（f-ERG）检查;采用HE染色、LFB染色、Bielschowsky银染分别评估视神经炎性细胞浸润、髓鞘脱失、轴突病理改变;使用TUNEL法检测视网膜神经节细胞凋亡并计算凋亡指数.对两组实验数据采用t检验进行统计学分析.结果 NGF组与BSS组小鼠发病时间和临床评分比较,差异均无统计学意义（t=-1.844,P=0.079;t=-2.012,P=0.059）.在不同时间点,NGF组和BSS组的f-VEP差异均无统计学意义（P＞0.05）.在免疫后的第14天,NGF组f-ERG b波潜伏期较BSS组缩短,振幅较BSS组增大,两组差异有统计学意义（t=5.909,P=0.000;t=3.602,P=0.043）.LFB染色示,NGF组和BSS组视神经的脱髓鞘面积占横截面比例分别为（31.50±8.72）%、（29.91±10.00）%,差异无统计学意义（t=0.298,P=0.709）.TUNEL检测结果示,NGF组小鼠视网膜神经节细胞凋亡指数[（15.18±3.36）%]低于BSS组[（34.14±3.83）%],差异有统计学意义（t=11.790,P=0.000）.结论 NGF可以促进脱髓鞘性视神经炎小鼠视网膜神经节细胞的存活,对其视网膜神经组织可能具有一定的保护作用.     

Retinal ganglion cell numbers and delayed retinal ganglion cell death in the P23H rat retina

The P23H-1 rat strain carries a rhodopsin mutation frequently found in retinitis pigmentosa patients. We investigated the progressive degeneration of the inner retina in this strain, focussing on retinal ganglion cells (RGCs) fate. Our data show that photoreceptor death commences in the ventral retina, spreading to the whole retina as the rat ages. Quantification of the total number of RGCs identified by Fluorogold tracing and Brn3a expression, disclosed that the population of RGCs in young P23H rats is significantly smaller than in its homologous SD strain. In the mutant strain, there is also RGC loss with age: RGCs show their first symptoms of degeneration at P180, as revealed by an abnormal expression of cytoskeletal proteins which, at P365, translates into a significant loss of RGCs, that may ultimately be caused by displaced inner retinal vessels that drag and strangulate their axons. RGC axonal compression begins also in the ventral retina and spreads from there causing RGC loss through the whole retinal surface. These decaying processes are common to several models of photoreceptor loss, but show some differences between inherited and light-induced photoreceptor degeneration and should therefore be studied to a better understanding of photoreceptor degeneration and when developing therapies for these diseases.