玻璃体视网膜交界面超微结构及其年龄相关性改变

玻璃体视网膜交界面由玻璃体基底部、玻璃体后皮质与视网膜内界膜构成。玻璃体基底部借Ⅱ型胶原垂直插入内界膜形成紧密连接,玻璃体后皮质区则经“分子胶”模型、新糖蛋白模型及核纤层蛋白细胞模型形成相对松散的连接。随着年龄增长,玻璃体基底部后缘会逐渐向后延伸形成新的紧密连接,而玻璃体后皮质区则会由于内界膜增厚、基质降解酶浓度升高、自由基累积等致使玻璃体视网膜交界面粘连作用减弱,甚至形成玻璃体后脱离。玻璃体黄斑牵拉综合征、黄斑裂孔、孔源性视网膜脱离等玻璃体视网膜交界面疾病均被证实与玻璃体视网膜交界面状态密切相关。正确认识玻璃体视网膜交界面超微结构及年龄相关性改变是了解玻璃体视网膜交界面疾病的基础。     

视网膜表面膜的超微结构特征

目的 探讨视网膜收缩膜细胞与胶原作用的超微结构特征及细胞外间质的作用。方法 对１６例孔源多膜脱离伴增殖性玻璃体视网膜病变（ｐｒｏｌｉｆｅｒａｔｉｖｅ ｖｉｔｒｅｏｒｅｔｉｎｏｐａｔｈｙ,ＰＶＲ）患者行玻璃体切除术,并应用免疫胶体金标记技术对术中获得的视网膜表面膜进行细胞外间质（ｅｘｔｒａｃｅｌｌｕｌａｒ ｍａｔｒｉｘ,ＥＣＭ）－－Ⅰ和Ⅲ型胶原及纤维粘连蛋白（ｆｉｂｒｏｎｅｃｔｉｏｎ,ＦＮ）的免疫电     

高血压大鼠视网膜超微结构改变及开搏通终身治疗后的观察

应用眼底镜及光电镜观察高血压大鼠及开搏通终身治疗后大鼠的眼底变化及视网膜超微结构改革，并以正常大鼠做对照组，结果表明：高血压组眼底见动静脉管径比为１：２，动脉痉挛变细，反光增强，管径粗细不匀，相当于第Ｉ、ＩＩ级高血压眼底。光镜下见：视网膜毛细血管基膜增厚，管腔狭窄致视网膜缺血、缺氧。电镜下主要病变在视细胞外节及节细胞，视细胞外节基底部新生的膜盘模糊；多数节细胞水肿，胞浆淡染，线粒体空泡化，滑面内质     

人视网膜前体细胞超微结构特征

目的 观察体外培养的人视网膜前体细胞的超微结构特征。 方法 选取6例5个月人胚胎眼12只，每例取1只眼视网膜行视网膜前体细胞培养后进行透射电子显微镜观察，另一只眼直接行透射电子显微镜观察。 结果 在胚胎5个月的人视网膜神经上皮层细胞核内出现了大量的异染色质，细胞核呈不规则形。神经上皮层中有少量原始细胞散在分布，细胞核体积大，表面光滑，充满大量的常染色质，核仁明显。体外培养的视网膜前体细胞显示出原始细胞的超微结构特征:有巨大的细胞核，几乎占据整个细胞的体积，细胞浆极少，核仁明显，有大量的常染色质，几乎看不到异染色质。神经球样细胞团内，细胞间紧密贴附，外围细胞体积较大，可见到核分裂相。 结论 体外培养的人视网膜前体细胞具有原始细胞的超微结构特征。 (中华眼底病杂志, 2006, 22: 185-187)     

晚期青光眼视网膜超微结构的观察

目的 为研究青光眼视网膜的病理改变。方法 用透射电镜观察了６例（６只眼）晚期青光眼的视网膜超微结构的改变。结果 发现视网膜神经纤维层明显变薄，轴突严重破坏并丧失，神经节细胞几乎消失，可见大量细胞样体。视网膜内、外核层神经细胞数目减少、变性、排列紊乱，视杆、视锥细胞外节变性水肿。结论 提示青光眼的病理改变主要是神经节细胞及其轴突变性、萎缩。这些病理改变导致青光眼视功能永久性损害。     

次声暴露对大鼠血视网膜屏障超微结构的损害

目的 观察次声暴露对大鼠血视网膜屏障超微结构和通透性的作用。方法 将15只Sprague-Dawley(SD）大鼠分为：实验组12只，给予8Hz,130dB基础噪音的次声暴露，2h/d，分别于暴露后1，7，14及21d，用20g/L戊巴比妥钠腹腔麻醉动物，10min后取其眼球，均以硝酸镧（La)作为示踪剂，采用镧苯滴注固定法制备电镜样品。对照组3只，亦置于次声舱中2h/d，但不接受次声暴露，结果 在次声作用下，暴露1d时La的渗漏无明显变化，7d时沉积在内节间，到达光感受器细胞核层，14d时在神经细胞间隙出现La颗粒，21d时到达神经及玻璃体，而形态学改变并不明显，主要是代谢方面的变化，如线粒体肿胀，内质网扩张，糖原颗粒的沉积，核周周隙增宽等。提示随时间的延长，血视网膜屏障的损害加重。结论 次声可影响一定程度的血视网膜屏障通透性，而致视觉功能损伤。     

兔孔源性视网膜脱离的多焦视网膜电图及超微结构改变

目的研究视网膜脱离后多焦视网膜电图和视网膜超微结构改变。方法对9只18眼健康有色素家兔,制造孔源性视网膜脱离模型,造模前及造模后检测多焦视网膜电图,并于透射电镜下观察视网膜超微结构改变。结果视网膜脱离后10 d,与造模前比较有色素家兔多焦视网膜电图的P1波振幅密度降低(P=0.013),P1波振幅降低(P=0.01),N1波幅值降低(P=0.053)。光镜下神经上皮层的颗粒层变薄,神经纤维层和内颗粒层可见空泡。透射电镜可见:视网膜色素上皮细胞表面纤毛完全消失,视网膜色素上皮细胞内颗粒减少,粗面内质网、线粒体嵴断裂,外颗粒层细胞排列紊乱,视细胞外段盘膜粗大,盘膜间隙增宽,内外丛状层空泡形成,神经节细胞、细胞器大部分消失,神经节细胞层可见细胞质有嵴性肿胀。结论孔源性视网膜脱离后10 d,视网膜全层即发生病理改变,多焦视网膜电图的P1波振幅密度降低,P1波振幅和N1波振幅降低。     

复杂视网膜脱离视网膜下膜超微结构研究

目的研究复杂视网膜脱离病例中视网膜下膜的超微结构特征,探讨视网膜下膜的细胞成分。方法对21例复杂孔源性视网膜脱离伴视网膜下膜者行玻璃体切割术加视网膜下膜切除术,将所获得的视网膜下膜经处理后于光镜下选择细胞较密集处做超薄切片,染色后行透射电镜观察并摄影。结果复杂视网膜脱离视网膜下膜中,色素上皮细胞多呈散在分布,未见明显基底膜供细胞附着,在条索或片状膜当中的色素上皮细胞形态存在变化。神经胶质细胞胞浆内有较丰富的细胞器和直径约10nm的中间型微丝形成。视网膜下膜的细胞间质含有大量胶原纤维。成纤维细胞形状不规则,活跃,胞浆中见大量直径4～6nm微丝。结论视网膜下膜主要由视网膜色素上皮细胞、神经胶质细胞、成纤维细胞和胶原纤维组成。视网膜下膜中色素上皮细胞、神经胶质细胞和成纤维细胞有转化与增殖能力。     

实验性视网膜脱离复位后的视网膜细胞超微结构观察

目的 研究视网膜脱离复位后视网膜超微结构改变,以探讨视功能恢复障碍的机制。方法 12只灰兔通过在视网膜下注射透明酸钠的方法建立视网膜脱离模型。用透射电镜观察术后1,2,3,4周的视网膜。结果 视网膜复位早期光感受器外节段缺失、断裂。内节、视细胞核、双极细胞、神经节细胞均可见胞浆水肿,线粒体肿胀和嵴断裂。复位3周后,视网膜细胞结构基本正常,但仍有部分外节变短,神经纤维空洞存在。结论 视网膜复位后不仅光感受器,而且视网膜其他细胞和神经纤维均有不可逆的改变,这些改变导致视功能恢复不良。     

体外培养兔视网膜细胞损伤后的形态变化

目的：观察体外培养的兔视网膜细胞在受到机械损伤后的形态变化。方法：建立乳兔视网膜细胞及与Ｓｃｈｗａｎｎ Ｃｅｌｌ（ＳＣ）共培养模型,采用机械刮损方法对视网膜细胞造成损伤,相差显微镜下连续２４小时观察细胞对损伤的反应。结果：刮损后３０分钟胶质细胞逐渐移向损伤区,分裂增殖并填补裸区。神经元突起在损伤后６小时开始再生,其生长方向受到周围环境影响,具有“可塑性”。与ＳＣ共培养时,损伤后３小时即可发现再生突     

Investigations on Retinal Pigment Epithelial Damage at Laser Irradiation in the Lower Microsecond Time Regime

PurposeNew lasers with a continuous wave power exceeding 15 W are currently investigated for retinal therapies, promising highly localized effects at and close to the Retinal Pigment Epithelium (RPE). The goal of this work is to evaluate mechanisms and thresholds for RPE cell damage by means of pulse durations up to 50 µs.MethodsA diode laser with a wavelength of 514 nm, a power of 15 W, and adjustable pulse durations between 2 µs and 50 µs was used. Porcine RPE-choroidal explants (ex vivo) and chinchilla bastard rabbits (in vivo) were irradiated to determine threshold radiant exposures for RPE damage H¯Cell by calcein vitality staining and fluorescence angiography, respectively. Thresholds for microbubble formation (MBF) H¯MBF were evaluated by time-resolved optoacoustics. Exemplary histologies support the findings.Results H¯MBF is significantly higher than H¯Cell at pulse durations ≥ 5 µs (P < 0.05) ex vivo, while at 2 µs, no statistically significant difference was found. The ratios between H¯MBF and H¯Cell increase with pulse duration from 1.07 to 1.48 ex vivo and 1.1 to 1.6 in vivo, for 5.2 and 50 µs.ConclusionsCellular damage with and without MBF related disintegration are both present and very likely to play a role for pulse durations ≥ 5 µs. With the lower µs pulses, selective RPE disruption might be possible, while higher values allow achieving spatially limited thermal effects without MBF. However, both modi require a very accurate real-time dosing control in order to avoid extended retinal disintegration in this power range.     

Experiment Study of Retinal Ultrastructure after Intravitreal FK506

Purpose : To investigate the retinal toxicity of FK506 by intravitreal administration.Methods:Twenty-two eyes of 14 New Zealand rabbits were investigated. FK506 at concentrations of 5,25 and 50μg/eye was injected into the vitreous cavities respectively.The control eyes were received mixed solution of balanced salt and ethanol. All eyes were examined by tonometry, slit lamp and indirect ophthalmoscopy preoperatively and postoperatively at the 1^st, 3^rd, 7^th, and 14^th day respectively. In the final examination, all eyes were enucleated and processed for light and electron microscopy.Results: No evidence of toxic reaction was seen in the eyes received 25μg FK506 or less of FK506. Several eyes received 50μg FK506 and control eyes developed conjunctival congestion and slightly bloody exudates in anterior chamber which may be related to irritation of ethanol. Two of five eyes received 50μg developed transient vitreous opacities.Electron microscopically, the mitochondria of the photoreceptor cells were swelled in the eyes treated with 50μg FK506.Conclusion : It is safety with intravitreal FK506. There are no irritation and toxicity to the rabbits eyes with the intravitreal doses of 251.zg FK506 or less. The doses of 50μg FK506 are proved to be toxic to the retina.     

Liposome-bound cyclosporine: Retinal toxicity after intravitreal injection

The retinal toxicity of intraocular liposome-bound cyclosporine was studied in albino rabbits by means of electrophysiology and histopathology. During a followup period of one month, no histopathological or electroretinographic changes were noted using concentrations of 100, 200 and 500 micrograms injected intravitreally.     

玻璃体出血对视网膜损伤的电生理研究

通过对家兔玻璃体出血模型的视网膜电镜观察，结果表明，出血后７天，ａ，ｂ波幅显著下降，２８天时仍有明显改变，与病理改变相一致，且ａ波幅下降的幅度大于ｂ波，对其意义进行了讨论。     

Retinal displacement after surgery for idiopathic macular hole

AIM: To review and summarize the mechanism hypothesis, influencing factors and possible consequences of macular retinal displacement after idiopathic macular hole (IMH) surgery. METHODS: PubMed and Web of Science database was searched for studies published before April 2023 on “Retinal displacement”, “Idiopathic macular holes”, and “Macular displacement”. RESULTS: Recently, more academics have begun to focus on retinal displacement following idiopathic macular holes. They found that internal limiting membrane (ILM) peeling was the main cause of inducing postoperative position shift in the macular region. Moreover, several studies have revealed that the macular hole itself, as well as ILM peeling method, will have an impact on the result. In addition, this phenomenon is related to postoperative changes in macular retinal thickness, cone outer segment tips line recovery, the occurrence of dissociated optic nerve fiber layer (DONFL) and the degree of metamorphopsia. CONCLUSION: As a subclinical phenomenon, the clinical significance of postoperative macular displacement cannot be underestimated as it may affect the recovery of anatomy and function.     

漂浮物感与视网膜玻璃体退行性病变

对有漂浮物感者234例(312眼)散瞳经裂隙灯Goldmann三面镜或联合1060型巩膜压陷器检查,结果发现视网膜与玻璃体有不同程度退行性病变者分别为52.2%和77.2%,其中格子样变性为30.1%,萎缩性裂孔为9.3%,牵引性裂孔为4.5%,玻璃体后脱离为20.8%。近视眼或漂浮物感同时有闪光感者,视网膜及玻璃体退行性病变的患病率均高(P<0.01)。弥散性细尘状漂浮物感者牵引性裂孔的患病率高(P<0.01)。     

多点与单点模式激光术后视网膜组织变化的实验观察

目的　比较５３２ｎｍ激光多点模式与单点模式术后视网膜组织形态学变化。方法　健康成年无眼疾青紫蓝兔３２只随机分为多点模式组与单点模式组,两组按光凝后观察时间１ｄ、７ｄ、１４ｄ及２８ｄ再分为４个亚组,每亚组４只。左眼为空白对照组,右眼为实验组,分别于建立模型后相应时间点获取兔眼标本,在光镜和电镜下观察光凝区视网膜组织病理学变化。结果　单点模式组和多点模式组光凝后１ｄ、７ｄ光斑区略隆起,视锥、视杆细胞和外核层细胞可见凝固坏死,视网膜色素上皮层轻度隆起,线性结构破坏,视网膜神经感觉层（ｒｅｔｉｎａｌｎｅｕｒｏｅｐｉｔｈｅｌｉａｌｌａｙｅｒ,ＲＮＬ）水肿增厚,与空白对照组比较差异均有统计学意义（均为Ｐ＜０．０５）。光凝后１４ｄ、２８ｄ两组ＲＮＬ水肿均基本恢复,光斑中央区ＲＮＬ变薄、凹陷。单点模式组光凝后１４ｄ、２８ｄ和多点模式组光凝后２８ｄＲＮＬ厚度与空白对照组比较差异均有统计学意义（均为Ｐ＜０．０５）,而多点模式组光凝后１４ｄＲＮＬ厚度与空白对照组比较差异无统计学意义（Ｐ＞０．０５）。单点模式组和多点模式组光凝后１ｄ、７ｄ、１４ｄ、２８ｄＲＮＬ厚度比较差异均有统计学意义（均为Ｐ＜０．０５）。单点模式组光凝后２８ｄ视网膜色素上皮细胞和纤维组织增生,有些光斑处甚至可见有新生血管长入。结论　多点模式对视网膜的损伤较单点模式小,可以达到和单点模式相同的治疗效果,并且激光副作用较小。     

An Analysis of Metabolic Changes in the Retina and Retinal Pigment Epithelium of Aging Mice

PurposeThe purpose of this study was to present our hypothesis that aging alters metabolic function in ocular tissues. We tested the hypothesis by measuring metabolism in aged murine tissues alongside retinal responses to light.MethodsScotopic and photopic electroretinogram (ERG) responses in young (3–6 months) and aged (23–26 months) C57Bl/6J mice were recorded. Metabolic flux in retina and eyecup explants was quantified using U-¹³C-glucose or U-¹³C-glutamine with gas chromatography-mass spectrometry (GC-MS), O₂ consumption rate (OCR) in a perifusion apparatus, and quantifying adenosine triphosphatase (ATP) with a bioluminescence assay.ResultsScotopic and photopic ERG responses were reduced in aged mice. Glucose metabolism, glutamine metabolism, OCR, and ATP pools in retinal explants were mostly unaffected in aged mice. In eyecups, glutamine usage in the Krebs Cycle decreased while glucose metabolism, OCR, and ATP pools remained stable.ConclusionsOur examination of metabolism showed negligible impact of age on retina and an impairment of glutamine anaplerosis in eyecups. The metabolic stability of these tissues ex vivo suggests age-related metabolic alterations may not be intrinsic. Future experiments should focus on determining whether external factors including nutrient supply, oxygen availability, or structural changes influence ocular metabolism in vivo.     

Choroidal and Retinal Changes After Systemic Adrenaline and Photodynamic Therapy in Non-Human Primates

PurposeTo determine the tomographic, angiographic, and histologic changes in the choroid and retina of cynomolgus monkeys after systemic adrenaline and verteporfin photodynamic therapy (vPDT).MethodsSix cynomolgus monkeys (12 eyes) were treated with vPDT only (n = 2), adrenaline only for eight weeks (n = 2), adrenaline for eight weeks with vPDT at week 4 (n = 4), and adrenaline for 12 weeks and vPDT at week 8 (n = 4). Spectral-domain optical coherence tomography, angiography, and autofluorescence were performed at baseline and every 14 days thereafter until 28 days after adrenaline therapy or vPDT. Choroid parameters included choroidal thickness (CT) changes and structural changes using semiautomated image binarization. Histology with light and electron microscopy was performed.ResultsAdrenaline resulted in subfoveal CT increase at week 4 compared with baseline (3.4%, P = 0.010), with further increase at week 8 (3.9%, P = 0.007). This correlated with choroidal luminal area increase (16.0% at week 8 compared with baseline, P = 0.030). Outer retinal changes included subretinal fluid, ellipsoid zone (EZ) disruption, photoreceptor elongation, and sub/intraretinal bright dots. Hypocyanescent spots surrounded by leakage was observed. Histology showed dilated choroidal vessels, intracytoplasmic vacuoles, and retinal pigment epithelium (RPE) enlarged basal infoldings. The vPDT decreased subfoveal CT at four weeks after vPDT (−7.5%, P = 0.007). This correlated with choroidal stromal area decrease (−18.0%, P < 0.010). Within the treatment spot, there was outer retinal atrophy, EZ disruption, irregular RPE thickening, intense hypoautofluorescence, hyperfluorescence, and hypocyanescence. On histology, there were outer retina, RPE, and choroid changes.ConclusionsAdrenaline induces choroidal vessel dilation and CT increase. The vPDT decreases CT because of a reduction in choroidal stromal component.