青光眼动物模型DBA／2J小鼠的眼部特征及组织学观察

目的评价不同月龄DBA／2J小鼠的眼压、眼部特征及组织学变化。方法清洁级DBA／2J小鼠36只,3、5、7、9、11、14月龄各6只,3、9、14月龄的C57BL／6J小鼠各6只为对照。分别对实验鼠行眼前节照相,前房微管法眼压测量。用尼氏染色法对鼠视网膜切片进行染色并在光学显微镜下行视网膜神经节细胞（RGCs）计数,光学显微镜下对视网膜冰冻切片行视盘的形态学观察。结果鼠眼前节检查表明,DBA／2J小鼠从5月龄始逐渐发生虹膜色素播散、虹膜萎缩,虹膜透照可见瞳孔变形。眼压从7月龄开始升高,9月龄眼压升至高峰,14月龄降至对照组水平。各月龄DBA／2J小鼠眼压间的差异有统计学意义（F=27．600,P〈0．05）,各月龄C57BL／6J小鼠眼压间的差异无统计学意义（F=0．249,P=0．781）。DBA／2J鼠RGCs数量从7月龄开始减少,9～11月龄减少明显,各月龄DBA／2J鼠RGCs计数间的差异有统计学意义（F=23．594,P=0．000）,各月龄C57BL／6J小鼠RGCs计数的差异无统计学意义（F=1．816,P=0．211）。DBA／2J小鼠视盘凹陷于9～14月龄开始逐渐加深,而各月龄C57BL／6J小鼠的视盘形态无明显变化。结论随月龄的增长,DBA／2J小鼠眼前节病变逐渐加重,表现出继发性青光眼的相关形态学改变。DBA／2J小鼠是研究青光眼发病机制和视神经保护较好的动物模型。     

DBA/2J高眼压模型小鼠和正常BL6小鼠眼犬尿氨酸转氨酶-Ⅱ的表达差异

目的探讨犬尿氨酸转氨酶-Ⅱ（KAT—Ⅱ）在不同年龄的正常BL6小鼠与DBA／2J高眼压模型小鼠眼中的表达差异。方法将3、6、11月龄的BL6和DBA／2J小鼠全眼组织冰冻切片，通过免疫组织化学和DAPI双荧光染色法检测KAT-Ⅱ的表达及差异，双激发波荧光显微镜观察拍照。结果两系小鼠眼组织中，KAT-Ⅱ表达于角膜上皮、内皮，腱状体上皮和腱状肌内血管内皮，视网膜节细胞层。3、6月龄的DBA／2J小鼠眼角膜上皮和视网膜神经节细胞（RGCs）表达比BL6明显增强。BL6小鼠腱状体组织中6个月时KAT-Ⅱ表达最强，因DBA／2J腱状突发育不良而无法进行比较。结论KAT-Ⅱ在眼前节中的表达和在DBA／2J小鼠眼中的表达增强，提示KAT—Ⅱ可能参与眼压增高和视网膜变性等病理过程。     

神经球蛋白对慢性高眼压小鼠视网膜神经节细胞损伤的保护作用

背景 神经球蛋白(Ngb)是2000年发现的球蛋白,可以在缺氧或氧化应激的环境中保护细胞.Ngb在视网膜神经元中呈高表达,提示视网膜很可能是Ngb发挥其功能的重要场所. 目的 研究Ngb对小鼠高眼压所致视网膜神经节细胞(RGCs)损伤的保护作用及作用机制. 方法 本研究分为体外实验和体内实验两部分.将体外纯化培养的成年野生型(WT)小鼠和本实验室培育的Ngb转基因(Ngb-Tg)新生小鼠RGCs用不同浓度的谷氨酸作用3d后,以dead/live双染试剂盒染色计算RGCs的存活率,比较Ngb对不同浓度谷氨酸环境下培养的RGCs存活率的影响.将聚苯乙烯荧光微球注入WT和Ngb-Tg小鼠前房内以制备小鼠慢性高眼压模型,将小鼠分为WT小鼠对照组(n=18)、Ngb-Tg小鼠对照组(n=18)、WT小鼠微球单次注射组(n=38)、Ngb-Tg小鼠微球单次注射组(n=38)、WT小鼠微球2次注射组(n=6)及Ngb-Tg小鼠微球2次注射组(n=6).另设WT小鼠PBS注射组(n=6)、Ngb-Tg小鼠PBS注射组(n=6)观察PBS前房注射对眼压的影响.分别于前房注射微球后即刻(对照组),3d及1、4、8周处死小鼠,用实时荧光定量PCR、Western blot和免疫组织化学法定量分析Ngb mRNA及其蛋白在视网膜中的表达变化和RGCs的存活率,并对比两种小鼠视网膜中过氧化物和ATP表达水平. 结果 5.0、7.5、10.0 mmol/L谷氨酸处理后Ngb小鼠RGCs存活率均明显高于WT小鼠,差异均有统计学意义(t=2.810、3.020、3.110,P＜0.01).WT小鼠微球单次注射组及Ngb-Tg小鼠微球单次注射组小鼠眼压均明显高于WT小鼠对照组及WT小鼠PBS注射组,高眼压状态持续至4周,2次微球注射后眼压复升,高眼压可维持至8周.WT小鼠微球单次注射组第3天视网膜中Ngb含量明显上调,而Ngb-Tg小鼠视网膜中Ngb呈持续高表达.与Ngb-Tg小鼠相比,WT小鼠RGCs凋亡率在前房注射微球后第1、4、8周均逐渐升高,差异均有统计学意义(P＜0.05).1周时,Ngb-Tg小鼠微球单次注射组视网膜中DHE含量明显低于WT小鼠微球单次注射组(t=3.212,P=0.008),而ATP的含量则明显高于WT小鼠微球单次注射组(t=2.864,P＜0.01). 结论 Ngb可能是青光眼损伤的内源性神经保护因子,对高眼压所致RGCs损伤有保护作用,其机制可能是通过降低氧化应激和改善线粒体功能实现的.     

Tenomodulin抑制氧诱导视网膜病变小鼠模型新生血管形成的研究

目的探讨Tenoinodulin（TeM）蛋白对C57BL／6J小鼠早产儿视网膜病变模型（ROP）视网膜新生血管形成的抑制作用。方法将60只7d龄C57BL／6J幼鼠随机分为高氧组（ROP组）、正常对照组各15只和TeM组30只。将ROP组小鼠置于体积分数（75％±2％）的高氧环境中5d,随后回到正常氧环境中饲养5d;对照组小鼠饲养在正常氧环境中;TeM组是将鼠1只眼玻璃体腔内注射1μg TeM,对侧眼注射PBS作为对照,然后置于体积分数（75％±2％）的高氧环境中饲养5d,之后返回正常氧环境中。17d时处死全部小鼠,收集各组眼球。视网膜荧光素灌注铺片观察视网膜血管的改变、计算视网膜无灌注区的面积;计数突破内界膜的内皮细胞数反映视网膜血管增生情况,观察TeM蛋白对视网膜新生血管形成的抑制作用及对视网膜可能的毒性反应;Western blot检测TeM蛋白在视网膜内的表达。结果与高氧组（2．94±0．55）mm^2。及TeM组中对侧眼注射PBS（2．83±0．46）mm^2的视网膜铺片中央非灌注区面积（mm^2）相比,注射TeM的视网膜铺片（0．44±0．26）mm^2,其中央非灌注区面积差异有统计学意义（P〈0．01）;每个视网膜切面突破内界膜的内皮细胞核数（10．57±2．95）与前二者（44．93±6．78、41．07±7．31）比较差异均有统计学意义（P〈0．01）。注射TeM的视网膜冰冻切片未见炎症反应和细胞毒性破坏。Western blot检测结果显示注射TeM的视网膜呈阳性表达,注射PBS的视网膜未出现条带反应,TeM的相对分子质量约为16000。结论TeM可有效抑制视网膜新生血管的形成,预示着TeM在预防和治疗眼部新生血管方面具有潜在的作用。     

慢性高眼压大鼠模型视网膜中Brn-3a表达的动态变化

背景Brn-3a是最近发现的一种视网膜神经节细胞（RGCs）特异性标记物。高眼压的视功能损害主要与RGCs损伤有关,但高眼压大鼠视网膜损伤与Brn-3a表达的关系尚不清楚。目的观察慢性高眼压大鼠不同时期眼压、视网膜的形态学和Brn-3a表达的变化。方法将35只健康成年SD大鼠用随机数字表法随机分为正常对照组5只和模型组30只,术前测量眼压。模型组大鼠一侧眼用Shareef—Sharma手术方法建立慢性高眼压模型,对侧眼只切开结膜,不烙闭巩膜表层静脉作为伪手术眼。按照术后不同处理时间随机将模型组分为术后1、3、5、7、14、28d组共6个亚组,每组5只。分别于术前及术后30min,1、3、7、14、28d用Tono—Pen接触式眼压笔测量双眼眼压。各模型组于术后各相应时间点与正常对照组分别取5只大鼠过量麻醉处死,制作视网膜石蜡切片行常规组织病理学检查,评价视网膜形态变化,用甲苯胺蓝染色法计数RGCs,采用免疫组织化学法检测各时间点各组大鼠Brn-3a在RGCs中的表达。结果高眼压模型组大鼠术后各时间点眼压均明显高于术前,差异有统计学意义（F=95．631,P=0．001）,术后28d时眼压是正常对照组大鼠眼压的1．59倍。与伪手术眼相比,模型眼术后各时间点眼压均明显升高,差异均有统计学意义（q=18．418、15．261、10．987、6．931、4．975、2．962,P〈0．05）。正常对照组RGCs数量为（29．08±1．98）个／高倍视野,造模后3、5、7、14、28d组大鼠RGCs计数逐渐下降,差异均有统计学意义（t=5．943、8．034、15．023、17．004、19．371,P〈0．05）。免疫组织化学染色表明,随着造模时间的延长,各组Brn-3a阳性RGCs数量逐渐下降,差异有统计学意义（F=127．583,P=0．000）。结论采用Shareef—Sharma法可成功建立大鼠慢性高眼压动物模型,其眼压为中等程度升高;高眼压持续时间越长,RGCs的丢失越多。Brn-3a仅在RGCs层表达,随眼压持续时间的增加,Brn-3a的表达减少。     

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。     

GDNF家族成员artemin在大鼠视网膜神经节细胞中的表达及其功能

目的观察胶质细胞系源性神经营养因子（GDNF）家族成员artemin在正常大鼠视网膜神经节细胞（RGCs）中的分布、表达及其功能。方法体外培养出生1～3d SD乳鼠的视网膜神经上皮细胞,免疫荧光染色检测RGCs中artemin的定位及表达,实时定量聚合酶链反应（real—time PCR）对RGCs中artemin进行定量检测。并用40mmol／L葡萄糖处理细胞12h后,再进行上述检测,观察高糖对于RGCs中artemin表达的影响。结果免疫荧光的结果证实了培养的RGCs出现Thy1．1抗体阳性的红色荧光,且多重荧光标记显示RGCs同时存在显示绿色荧光的artelnin抗体和红色荧光的Thy1．1抗体,表明artemin在RGCs中有分布。正常对照组中Thy1．1抗体阳性的细胞为（442±9）个／高倍视野,而40mmol／L高糖培养组中为（263±7）个／高倍视野,差异有统计学意义（P〈0．05）。Real—time PCR对大鼠RGCs中artemin的mRNA水平进行定量分析,40mmol／L葡萄糖处理视网膜神经细胞12h后,artemin在视网膜神经细胞及RGCs的表达明显下降（P〈0．05）。结论研究发现在原代培养的大鼠视网膜神经细胞及RGCs巾均有artemin的表达,并且在高糖作用下表达下降,为进一步研究artemin对受损RGCs的保护作用提供了思路。     

T、B淋巴细胞联合免疫缺陷对急性高眼压小鼠视网膜神经细胞的影响

目的研究T、B淋巴细胞联合缺陷对急性高眼压小鼠视网膜神经细胞的影响。方法选取重度联合免疫缺陷（SCID）小鼠和野生型C57BL／6小鼠各16只。2种小鼠分别随机取6只不做任何处理作为正常对照组,剩余10只作为模型组。采用前房穿刺的方法建立缺血一再灌注模型,每只小鼠取右眼为实验眼,左眼为模型对照眼。通过荧光金逆行标记技术,观察并计数再灌注后21d存活的视网膜神经节细胞（RGCs）;同时进行视网膜切片苏木精一伊红染色,观察再灌注后21d视网膜形态并测量内核层厚度。结果正常对照组SCID小鼠和C57BL／6小鼠的RGCs形态和数量、视网膜结构及厚度均无明显差异。视网膜缺血一再灌注损伤后21d,SCID小鼠RGCs的存活率为91％±5％,C57BL／6小鼠RGCs的存活率为78％±5％,二者比较差异有统计学意义（P=0．003）;SCID小鼠实验眼内核层厚度为（33．52±2．13）μm,模型对照眼为（34．06±3．00）μm,二者比较差异无统计学意义（P〉0．05）;C57BL／6小鼠实验眼内核层厚度为（22．44±1．70）μm,模型对照眼为（31．06±3．75）μm,二者比较差异有统计学意义（P=0．004）。结论急性高眼压模型中,T、B淋巴细胞联合免疫缺陷小鼠RGCs的存活率较高,视网膜损伤明显轻于野生型C57BL／6小鼠。     

神经营养因子与视网膜疾病的研究现状

近10年的研究显示神经营养因子能促进轴突切断和缺血后视网膜神经栉细胞（RGCs）的存活以及损伤后部分RGCs轴突的再生和保护变性疾病的光感受器。本文从神经营养因子的研究史、结构以及与视网膜疾病的研究现状出发，进一步阐述神经营养因子是一种可治疗视网疾病的有效方法。     

红景天苷对NMDA介导的小鼠视网膜神经节细胞损伤的保护作用

目的：探讨红景天苷（Sal）对视网膜神经节细胞（RGCs）凋亡的抑制作用。方法：实验研究。36 只C57BL6J小鼠随机分为空白组、模型对照组、不同浓度Sal实验组，每组6 只，均以右眼为实验眼。空白组仅注射0.9%PBS溶液，模型对照组和实验组玻璃体腔注射N-甲基-D-天（门）冬氨酸（NMDA）1.5 μl建立RGCs损伤模型；建模前48 h，模型对照组注射1.5 μl 0.9% PBS溶液，实验组玻璃体腔注射不同浓度Sal（0.1、0.4、2、8 mmol/L，1.5 μl）。建模5 d后制备视网膜标本，观察视网膜RGCs存活及凋亡情况，Western Blot法检测视网膜中Caspase-3、Caspase-8 蛋白的表达。数据采用单因素方差分析。结果：HE染色显示空白组视网膜RGCs无变化，模型对照组RGCs显著减少，不同浓度Sal实验组RGCs细胞核染色数目较模型对照组逐渐增加，并呈浓度依赖性；经视网膜平铺片测定RGCs 存活情况，发现空白组RGCs正常存活，模型对照组仅少量RGCs存活，不同浓度Sal组RGCs存活率较模型对照组提高，各组小鼠RGCs阳性细胞数比较差异有统计学意义（F=212.0，P < 0.001）。同时，8 mmol/L浓度的Sal实验组Caspase-3、Caspase-8 蛋白表达明显低于模型对照组，差异有统计学意义（F=168.3，P < 0.001）。结论：Sal可以抑制NMDA介导的RGCs凋亡，对RGCs损伤有保护作用。     

Time Course of Age-dependent Changes in Intraocular Pressure and Retinal Ganglion Cell Death in DBA/2J Mouse

Glaucoma is a major cause of irreversible blindness and is characterized by the death of retinal ganglion cells (RGCs) [1]. This death of RGCs is frequently associated with an elevation in intraocular pressure (IOP) [2].However, the understanding of how elevated IOP leads to cell death is hampered by the lack of an animal model that emulates the clinical time course for decades. Mouse studies have proven helpful for investigating human complex diseases. The DBA/2J mouse, which is inheri…     

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.     

Erythropoietin promotes survival of retinal ganglion cells in DBA/2J glaucoma mice

PURPOSE: Retinal ganglion cell (RGC) loss occurs in response to increased intraocular pressure (IOP) and/or retinal ischemia in glaucoma and leads to impairment of vision. This study was undertaken to test the efficacy of erythropoietin (EPO) in providing neuroprotection to RGCs in vivo. METHODS: The neuroprotective effects of EPO were studied in the DBA/2J mouse model of glaucoma. Mice were intraperitoneally injected with control substances or various doses of EPO, starting at the age of 6 months and continuing for an additional 2, 4, or 6 months. RGCs were labeled retrogradely by a gold tracer. IOP was measured with a microelectric-mechanical system, and EPO receptor (EPOR) expression was detected by immunohistochemistry. Axonal death in the optic nerve was quantified by para-phenylenediamine staining, and a complete blood count system was used to measure the number of erythrocytes. RESULTS: In DBA/2J mice, the average number of viable RGCs significantly decreased from 4 months to 10 months, with an inverse correlation between the number of dead optic nerve axons and viable RGCs. Treatment with EPO at doses of 3000, 6000, and 12,000 U/kg body weight per week all prevented significant RGC loss, compared with untreated DBA/2J control animals. EPO effects were similar to those of memantine, a known neuroprotective agent. IOP, in contrast, was unchanged by both EPO and memantine. Finally, EPOR was expressed in the RGC layer in both DBA/2J and C57BL/6J mice. CONCLUSIONS: EPO promoted RGC survival in DBA/2J glaucomatous mice without affecting IOP. These results suggest that EPO may be a potential therapeutic neuroprotectant in glaucoma.     

Investigating the effect of ciliary body photodynamic therapy in a glaucoma mouse model

PURPOSE: To investigate the morphologic and functional effects of verteporfin ciliary body photodynamic therapy (PDT) in a murine glaucoma model and normal mouse eyes. METHODS: A glaucomatous mouse strain, DBA/2J and a normal control mouse strain (C57BL/6) were used in the study. Verteporfin was injected intravenously at doses of 1.0 (DBA/2J) or 2.0 or 4.0 (C57BL/6) mg/kg. Transscleral irradiation of the ciliary body was performed with light at a wavelength of 689 nm delivered through an optical fiber, with irradiance of 1800 mW/cm2 and fluence of 100 J/cm2. Laser irradiation was applied for 360 degrees of the corneoscleral limbus in C57BL/6 normal mice and for 180 degrees in DBA/2J mice. Retreatment was performed in C57BL/6 normal mice that had been treated with 2.0 mg/kg of verteporfin at post-PDT day 7. One eye of each animal was treated, and the fellow eye served as the control. The morphologic effect of PDT on the ocular structures was assessed by light and electron microscopy. The IOP was measured using an applanation tonometer with a fiber-optic pressure sensor. Surviving retinal ganglion cells (RGCs) in DBA/2J mice eyes were retrogradely labeled with a neurotracer dye at 12 weeks after PDT. RESULTS: In all groups, almost all ciliary body blood vessels in the treated area were thrombosed 1 day after PDT. In DBA/2J mice, ciliary epithelium and stroma were severely damaged 1 day after PDT. The mean IOP in treated eyes was significantly reduced compared with that in the control eyes in all groups. The reduction of mean IOP in DBA/2J mouse eyes persisted for 7 weeks, although the mean IOP in normal mouse eyes treated with 2 or 4.0 mg/kg verteporfin returned to the level of the fellow control eyes by 7 and 17 days after treatment, respectively. The mean number of RGCs in the DBA/2J treated eyes was significantly higher than in control eyes. CONCLUSIONS: Ciliary body PDT resulted in morphologic changes in the ciliary body, significant reduction of IOP, and prevention of ganglion cell loss in a mouse glaucoma model. These results suggest that ciliary body PDT is a more selective cyclodestructive technique with potential clinical application in the treatment of glaucoma.     

The combined effect of brain-derived neurotrophic factor and a free radical scavenger in experimental glaucoma

PURPOSE. Brain-derived neurotrophic factor (BDNF) had a limited effect on the survival of retinal ganglion cells (RGCs) in rats' eyes with elevated intraocular pressure (IOP). The combined treatment of BDNF and a nonspecific free radical scavenger N-tert-butyl-(2-sulfophenyal)-nitrone (S-PBN) was investigated on the RGCs in hypertensive eyes of rats. METHODS: Adult Wistar rats were separated into five groups: BDNF (0.5 microg) + S-PBN; BDNF (1. 0 microg) + S-PBN; BDNF (1.0 microg); S-PBN; and phosphate-buffered saline. Right eyes served as normal controls (n = 10). RGCs were labeled with 5% Fluoro Gold; injected into the superior colliculus. Three days after intratectal injection, the episcleral veins of the left eyes were cauterized. Intravitreal injection of BDNF was performed on days 5, 13, 21, and 29 after IOP elevation. S-PBN was injected intraperitoneally (100 mg/kg body wt) every 12 hours starting 30 minutes after cauterization. RESULTS: The survival of RGCs using BDNF treatment alone in moderately hypertensive eyes and systemic administration of S-PBN alone did not significantly rescue the RGCs. However, the combination of BDNF and S-PBN increased the survival of RGCs to 90.1%. CONCLUSIONS: Trophic factors and antioxidants have synergistic effects on rescuing RGCs from death in eyes with elevated IOP. Further studies of different combined treatment therapies may provide avenues to save RGCs from death in eyes with elevated IOP.     

Retrograde axonal transport of BDNF in retinal ganglion cells is blocked by acute IOP elevation in rats

PURPOSE: To determine whether acute experimental glaucoma in rats obstructs retrograde transport of brain-derived neurotrophic factor (BDNF) to retinal ganglion cells (RGCs). METHODS: Forty rats had unilateral injection of either (125)I-BDNF (20 animals) or a mixture of (125)I-BDNF and 100-fold excess nonradiolabeled BDNF (20 animals). In each group of 20 animals, eyes contralateral to injection had either normal intraocular pressure (IOP; 10 animals) or IOP elevated to 25 mm Hg below the systolic blood pressure of the eye (10 animals). In each group of 20 rats, ipsilateral eyes had IOP set at systolic blood pressure (4 eyes), had optic nerve transection (10 eyes), or had normal IOP (6 eyes). Six hours after injection, animals were killed and tissues were fixed, embedded, and sectioned for autoradiography. Grain counts were performed over retina and optic nerve using automated image analysis. RESULTS: IOP elevation to 25 mm Hg below systolic blood pressure (perfusion pressure [PP] 25) decreased median retinal nerve fiber layer (NFL) grains by 38% compared with controls (P: < 0.001). Competition by cold BDNF reduced NFL grains by 28% (P: = 0.013). Considering only the radioactivity representing specific retrograde transport of BDNF, IOP elevation to PP25 reduced transport by 74%, whereas elevation to PP0 (equaling systolic blood pressure) reduced specific transport by 83%. CONCLUSIONS: BDNF is transported retrogradely from the superior colliculus in adult rats, and this transport is substantially inhibited by acute IOP elevation. Deprivation of BDNF among RGCs may contribute to neuron loss in glaucoma.     

Longitudinal evaluation of retinal ganglion cell function and IOP in the DBA/2J mouse model of glaucoma

PURPOSE: To characterize progressive changes of retinal ganglion cell (RGC) function and intraocular pressure (IOP) in the DBA/2J mouse model of spontaneous glaucoma. METHODS: Serial pattern electroretinograms (PERGs) and IOPs measures were obtained from both eyes of 32 anesthetized DBA/2J mice over an age range of 2 to 12 months at 1-month intervals. Cone-driven flash-ERGs (FERGs) were also recorded. The endpoint was defined as the age at which the PERG amplitude reached the noise level in at least one eye. At that point, both eyes were histologically processed to evaluate the thickness of the retinal fiber layer (RNFL). RESULTS: IOP increased moderately between 2 and 6 months ( approximately 14-17 mm Hg) and then more steeply, until it leveled off at approximately 28 mm Hg by 9 to 11 months. The mean PERG amplitude decreased progressively after 3 months of age to reach the noise level (85% reduction of normal amplitude) at approximately 9 to 12 months in different animals. When the PERG was at noise level, the RNFL showed a relatively smaller reduction (40%) in normal thickness. The FERG displayed minor changes throughout the observation period. IOP and PERG changes were highly correlated (r(2) = 0.51, P < 0.001). CONCLUSIONS: Results indicate that inner retina function in DBA/2J mice progressively decreases after 3 months of age, and it is nearly abolished by 10 to 11 months, whereas outer retina function shows little change and the RNFL thickness is relatively spared. This result suggests that surviving RGCs may not be functional. Progression of inner retinal dysfunction is strongly associated with increased IOP.     

DBA/2J小鼠房水引流通道中色素颗粒分布及其与眼压关系的实验研究

目的 探讨色素性青光眼动物模型DBA/2J小鼠房水引流通道中色素颗粒形态、大小、数量与眼压之间的关系.设计实验研究.研究对象9周龄雄性DBA/2J小鼠20只(40眼).方法 定期监测眼压和眼前节变化,12、20、28、36周龄随机各取3只(6眼),按眼压正常与否分成正常眼压和高眼压组.光镜观察不同眼压组房水引流通道结构...