急性高眼压模型兔眼不同眼压状态下视神经轴浆运输的改变

目的 观察急性高眼压模型兔眼不同眼压状态下视神经轴浆运输的改变。方法 成年新西兰大白兔24只,分为眼压20、30、40 mm Hg(1 mm Hg=0.133 kPa)组和眼压为10～15 mm Hg的对照组,每组均为6只兔。采用前房穿刺灌注法联合压力持续监测法建立急性高眼压模型。实验开始时,兔眼玻璃体腔中注射罗丹明异硫氰酸(RITC)标记轴浆运输。持续3h高眼压后,过量麻醉处死兔后取下视神经。荧光显微镜下观察视神经轴浆运输情况的改变。采用德国Leica公司Q500IW图像分析软件对RITC进行灰度定量分析,并对各眼压组平均灰度值和筛板前、筛板区、筛板后350 μm区域灰度值进行统计学分析处理。结果 RITC在视神经中心呈顺行标记染色。不同眼压组轴浆运输情况不同,随着眼压升高,轴浆运输能力减弱,差异有统计学意义(F=159.3,P＜0.05)。筛板前区,各眼压组间灰度值比较,差异无统计学意义(F=0.2545,P＞0.05)。40 mm Hg组灰度值与对照组灰度值比较,在筛板区（t=5.684）和筛板后350 μm区域（t=5.124）差异均有统计学意义(P＜0.05);20、30 mm Hg组灰度值与对照组灰度值比较,差异无统计学意义(t=1.747,P＞0.05)。结论 眼压40 mm Hg持续3h将导致视神经轴浆运输改变,轴浆运输障碍部位以筛板区及以后的区域为主。     

神经生长因子对兔急性高眼压视神经节细胞Bcl-2和Bax表达的影响

目的研究神经生长因子(nerve growth factor,NGF)对兔眼急性高眼压视网膜神经节细胞(retinal ganglion cells,RGCs)损伤的保护作用。方法健康成年新西兰大耳白兔30只,随机分为5组,每组6只,均一眼为高眼压模型眼,另一眼为自身对照眼,每组3只兔于术后每日肌肉注射NGF2000BU,5组兔分别于制造模型眼后第1天、第3天、第7天、第15天和第30天处死,用透射电镜观察线粒体的变化,免疫组织化学SABC法检测RGCs的Bcl-2、Bax蛋白表达,定量分析NGF的药物疗效。结果急性高眼压3d后,RGCs轴突中线粒体肿胀,空泡化,Bcl-2蛋白表达减少,Bax蛋白表达增多,Bcl-2/Bax比值下降,实验组与对照组相比差异有显著性(t=3.09,P<0.05);应用NGF7d后,治疗组线粒体肿胀程度减轻,Bcl-2表达增多,Bax表达减少,Bcl-2/Bax比值开始上升,治疗组与实验组相比差异有显著性(t=2.79,P<0.05),15d后,轴突中线粒体增多,30d后,线粒体形态、数量基本恢复正常,治疗组与实验组相比差异有极显著性(t=4.23,P<0.01)。结论NGF可改善急性高眼压RGCs的营养状况,保护线粒体,上调Bcl-2/Bax比值,促进RGCs功能的恢复,减轻急性高眼压后视网膜神经节细胞的损伤。     

视神经挫伤轴浆运输和超微结构变化的实验研究

目的 研究实验性视神经挫伤轴浆运输与超微结构的变化。方法采用自行设计的弹簧冲击器对家兔视神经进行定量损伤，术后1、3、7、14d应用辣根过氧化物酶(HRP)顺行标记和透射电镜观察视神经轴浆运输以及超微结构的变化。结果 不同时间实验组HRP反应产物较正常对照组明显降低，差异有显著性，HRP反应产物随观察时间延长逐渐增加，但至术后14d仍明显低于正常。电镜观察见损伤后1d大部分轴突颗粒状变性，线粒体肿胀，髓鞘松解，3d时损伤最重，14d部分轴突恢复正常。结论 视神经挫伤后局部轴浆运输发生障碍，同时轴突变性，14d部分轴突功能恢复。     

急性高眼压对兔视神经轴浆运输的影响——实验性青光眼

我院眼科学教研组实验性青光眼第二、二部分,对急性高眼压引起兔眼视网膜的病理变化,已分别利用光镜和电子显微镜做了观察。本实验用同样方法造成人工高眼压,以辣根过氧化酶(HRP)法,观察急性高眼压对视神经的轴浆运输的影响。为探讨青光眼视力改变的原因,做部分实验观察。     

藏红花提取液对兔慢性高眼压视神经轴突数目的影响

目的探讨慢性高眼压后兔眼视神经轴突数目的变化情况及藏红花提取液对视神经轴突损伤的保护作用。方法将新西兰白兔20只随机分为对照组、高眼压组、治疗I组和治疗Ⅱ组，每组均为5只兔10眼。高眼压组和治疗Ⅰ、Ⅱ组兔眼前房注入3g ·L^-1复方卡波姆溶液制作成慢性高眼压模型。治疗Ⅰ、Ⅱ组兔每日耳缘静脉推注藏红花提取液。4周后利用图像分析系统对视神经轴突数目及所占面积百分比进行定量测定。结果正常对照组与高眼压组、治疗Ⅰ组轴突数目比较有统计学意义（P〈0．05）；治疗Ⅱ组与正常对照组轴突数目比较无统计学意义（P〉0．05）。结论慢性高眼压可导致视神经轴突数量明显减少，藏红花提取液可通过各种途径显著增加视神经轴突的存活率，对视神经起到一定的保护作用。[眼科新进展2007；27（3）：173-175]     

青光安颗粒对兔急性高眼压视神经轴突的保护作用

目的:观察青光安颗粒对兔急性高眼压状态后视神经轴突及视网膜神经节细胞的保护作用。方法:家兔48只随机分成青光安治疗组、模型对照组,每组24只。用生理盐水灌注法1眼造成急性高眼压模型,另1眼则穿刺灌注不加压作为自身空白对照组,连续灌胃14d。分别于造模后7,14d处死,检测视网膜中NO及谷氨酸的含量,并观察视网膜的病理组织学改变。结果:7d后各组视网膜组织中NO、谷氨酸含量比较差异有显著性(P<0.01),治疗组和模型组中NO及谷氨酸含量均高于空白组,差异具有显著性(P<0.01,P<0.05),但治疗组明显低于模型组,差异亦具有显著性(P<0.01)。14d后治疗组中NO及谷氨酸含量均接近空白组,差异无显著性;但模型组仍明显高于空白组,差异具有显著性(P<0.05,P<0.01)。治疗组与模型组两组2wk之间比较差异均有显著性(P<0.05)。电镜结果表明,与模型组对比治疗组轴突肿胀较轻,轴浆内线粒体清晰数目较多,视网膜神经节细胞损伤较轻。结论:青光安能加速急性高眼压状态后视网膜组织中NO及谷氨酸的清除,对视神经轴突有保护性作用。     

纳络酮治疗兔放射性视神经损伤

目的探讨放射性视神经病变(radiation optic neurapathy,RON)的机制和防治办法。方法应用自行设计制作的兔固定架,固定新西兰大耳白兔头部,然后用60Co-γ射线以视交叉为中心包括视神经在内的范围进行照射,3Gy/d,共8d,总剂量为24Gy,对视神经进行定量损伤,治疗组应用纳洛酬(naloxone,NAL)治疗。照射后1、10、30、60d应用辣根过氧化物酶(horse radish peroxidase,HRP)顺行标记测定技术,观察视神经轴浆运输改变。结果照射组不同时期HRP积分吸光度与正常对照组差异均有显著性(P<0.05),照射组不同时期之间差异无显著性(P>0.05),治疗组60d与损伤对照组比较HRP积分吸光度差异有显著性(P<0.05)。结论放射线可导致视神经轴浆运输障碍,NAL在一定程度上对放射性视神经损伤有保护和治疗作用,为临床药物治疗该病提供了新的依据。     

兔慢性长期性高眼压模型建立

目的 建立家兔长期稳定性慢性高眼压模型.方法 将14只兔随机分为A、B两组,每组7只兔(14只眼).A组把长3 mm、宽2 mm的一次性输液管片从角巩膜缘植入前房;B组向前房内注入玻璃酸钠0.2 ml,术后不同时段对两组高眼压模型进行观察.结果 A组兔眼眼压术后7 d开始升高,持续升高至实验结束(观察2个月),平均眼压(32±4.37)mm Hg,最高峰值(35±3.58)mm Hg,模型建立成功率92%;B组100%兔眼眼压升高,但只能持续1～2 d,出现周边角膜膨出、角膜变形等并发症;3 d时无1眼眼压升高.结论 兔角巩膜缘植入一次性输液管材料能建立慢性长期性高眼压模型.     

重组人促红细胞生成素对急性高眼压兔眼视神经和视网膜超微结构的保护作用

目的:探讨重组人促红细胞生成素(recombinant human erythropoietin,rhEPO)对急性高眼压视网膜缺血所致的视神经和视网膜超微结构损害的保护作用。方法:将12只健康新西兰白兔平均分为模型组和EPO组。两组兔均任选1眼作为实验眼,用生理盐水前房灌注法造成急性高眼压模型。造模前第3d及造模结束时,EPO组兔皮下注射rhEPO100U/kg共两次。第7d进行视神经和视网膜的超微结构观察。结果:急性高眼压使视神经和视网膜的超微结构受到明显损害,全身使用rhEPO后这种损害显著减轻。结论:rhEPO能够减轻急性高眼压引起的视神经和视网膜超微结构损害。rhEPO可能成为新的视神经保护药物。     

碱性成纤维细胞生长因子对兔急性高眼压视神经纤维损害的保护作用

目的 观察急性高眼压对视神经的损害和碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)对视神经的保护作用。 方法 计算机图像分析技术定量分析视神经纤维数量。经前房灌注平衡液的方法,制造兔急性高眼压模型。应用bFGF玻璃体内注射后,观察视神经纤维数量变化。 结果 视网膜缺血组视神经纤维数量较正常明显减少(P=0.00003),bFGF治疗组视神经纤维数量较高眼压组明显增多(P=0.0078). 结论 急性高眼压视网膜缺血能造成视神经纤维数量明显减少。玻璃体内注射bFGF能减轻急性高眼压对视神经纤维所造成的损害。 (中华眼底病杂志,2000,16:94-96)     

Orthograde axonal transport of optic nerve and injury--morphological study

To investigate the effects of injury to the orthograde axonal transport in the optic nerve, horseradish peroxidase (HRP) was injected into the vitreous of the cat eye after various types of optic nerve injury, and the retina and optic nerve were examined with light and electron microscopes 8 hours after the injection. The optic nerve was sectioned in one eye at about 6 mm behind the eyeball and the optic nerve of the contralateral eye was used as the control. HRP reaction products were frequently observed within the retinal ganglion cells and their axons of the nerve fiber layer as well as in the retrolaminar optic nerve on the experimental side, and the findings were similar to those on the control side. The optic nerve was injured by cryocoagulation for 10 seconds or 30 seconds, and ischemic changes of various degrees were induced. Intracellular and intra-axonal HRP reaction products were markedly reduced at the retrolaminar portion, and the degree of reduction depended on the duration of cryocoagulation. The section of the optic nerve had, at least in the early stage, only minimal effects on the orthograde axonal transport, but the optic nerve injury accompanied by ischemic changes markedly blocked the axonal transport in both the inner part of the retina and the optic nerve.     

川芎嗪对兔高眼压视神经轴突损伤保护作用的研究

目的 探讨川芎嗪对兔持续性高眼压视神经轴突损伤的保护作用。方法 对３６只新西兰白兔眼前房注人α－糜蛋白酶,制作成持续性刘眼压模型后,随机等分为高眼压对照组和川芎嗪治疗组,治疗组于高眼压持续７ｄ始肌注川芎嗪,观察不同时间两组动物球结膜微循环变化及视神经轴突光、电镜结构改变。结果 与高眼压对照组相比,川芎嗪组结膜微循环障碍明显减轻（ｐ〈０．０１）,视神经轴突数目多、直径小,占视神经面积百分比高（Ｐ〈０     

乳兔雪旺细胞对成兔视神经挫伤修复的作用

目的 研究乳兔雪旺细胞(Schwann cell,SC)对成兔视神经挫伤修复的作用。 方法 建立成兔视神经挫伤模型,伤后24 h分别向伤眼玻璃体腔内注入SC悬液(A组)、生理盐水(B组)各0.1 ml。伤后不同时间点进行视网膜节细胞(retinal ganglion cell,RGC)、轴突染色记数及闪光视觉诱发电位(flash visual evoked potentials,FVEP)检测。 结果 伤后4周A、B组RGC平均记数分别为(19.89±3.79) /mm和(12.67±4.12) /mm,轴突密度分别为(94.569±793) /mm ²和(36.085±285) /mm²,A组明显高于B组(P<0.01)。伤后3 d A组伤眼与健眼FVEP幅值比由48%上升至88%,8周时仍为78%,各时间点均明显高于B组(P＜0.01)。 结论 乳兔SC能够提高成兔视神经挫伤后RGC存活率,减轻轴突变性,显著促进视神经功能恢复,对视神经挫伤修复具有明显的促进作用。(中华眼底病杂志,2000,16:91-93)      

Neuroprotective effects of brimonidine treatment in a rodent model of ischemic optic neuropathy

Ischemic optic neuropathy (ION) is a common disorder caused by disruption of the arterial blood supply to the optic nerve. It can result in significant loss of visual acuity and/or visual field. An ischemic optic nerve injury was produced in rats by intravenous injection of Rose Bengal dye followed by argon green laser application to the retinal arteries overlying the optic nerve, causing a coagulopathy within the blood vessels and disruption of optic nerve and retinal perfusion. The effect of brimonidine tartrate eye drops on survival of retinal ganglion cell axons in this experimental paradigm was studied. One eye was treated and the contralateral eye served as a control. Four groups of animals were used for this study. Group 1 received 7 days of treatment with 0.15% brimonidine tartrate eye drops twice a day prior to the ischemic injury. Group 2 animals received 0.15% brimonidine tartrate eye drops twice a day for 14 days after photocoagulation injury. Animal groups 3 and 4 received eye drops of 0.9% NaCl twice a day either daily for 7 days before injury or daily for 14 days, respectively. All rats were sacrificed 5 months after the injury to ascertain long-term optic axon survival. Coagulopathy-induced optic nerve ischemia resulted in a 71% loss of optic axons. Treatment with brimonidine daily for the 7 days prior to the injury resulted in a greater survival of optic axons, with only a 56.1% loss compared to control. Brimonidine treatment every day for 14 days after the ischemic injury did not result in a significant rescue of optic axons compared to injury alone. In summary, the application of brimonidine eye drops for one week prior to an ischemic injury resulted in a statistically significant increase in survival of optic axons within the injured optic nerves. Brimonidine treatment of the eye after the ischemic injury did not result in axon rescue, and axon loss was similar to the injured optic nerves treated with saline only. These results suggest that brimonidine may have potential use for prevention of ION in at-risk patients.     

Penetration of horseradish peroxidase into the optic nerve after vitreal or vascular injections in the developing chick

In order to determine whether a possible barrier exists to diffusion of tracer into the optic nerve during development and to provide a basis for later studies of retrograde axonal transport in embryonic nerves, we studied the diffusion of horseradish peroxidase (HRP) into the nerve after vitreal injections in chicks ranging in age from embryonic day 6 to 3 days after hatching. We found that HRP may reach the periaxonal spaces of the retrobulbar optic nerve after vitreal injection, vitreal injection into the opposite eye, or vascular injection. These and other observations suggest that vitreally injected HRP may reach the periaxonal spaces of the optic nerve by at least two routes: (1) by the obvious diffusion of marker from the vitreal surface into the optic nerve head and (2) by vascular leakage from fenestrated capillaries of the choriocapillaris into the pericapillary spaces of these and other capillaries that feed into the optic nerve parenchyma. There is a breakdown in the blood-brain barrier to HRP in the optic nerve head of the chick at embryonic day 13. The development of the breakdown depends at least in part on the maturation of vasculature in the nerve and the establishment of anastomotic branches between these vessels and those of the choriocapillaris. Our results further suggest that the limited diffusion of HRP into the retrobulbar nerve of fetal and newly hatched chicks is a function of uptake of tracer by glial cells within the nerve. Investigators of axonal transport who use this visual pathway as a model should be reminded of the potential artifact involved in this access of vascularly circulating label into the region of the lamina cribrosa.