Notch-1调控视网膜前体细胞向视网膜神经节细胞分化

目的研究Notch-1对视网膜前体细胞(RPC)向视网膜神经节细胞(RGC)分化的调控作用。方法分离培养胚胎14 d龄Sprague-Dawley大鼠的RPC，实验组和对照组分别用含有Notch-1反义寡核苷酸链和无关序列寡核苷酸链的培养液进行诱导分化14 d，倒置相差显微镜每天观察细胞的生长和分化情况，Thy1.1标记RGC并进行计数。结果实验组和对照组的RPC都能分化为多种视网膜细胞类型，包括Thy1.1阳性的RGC，但两组RPC向RGC分化的百分比不同。实验组和对照组RGC的百分比分别为(16.57±4.31)%和(31.19±6.90)%，两组比较差异有统计学意义（t=9.84,P＜0.001）。结论Notch-1对RPC的分化具有负向调控作用，阻断Notch-1能促进RPC向RGC分化。(中华眼底病杂志, 2007, 23: 101-103)     

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.     

移植含嗅鞘细胞和体外溃变的周围神经对成年大鼠视网膜神经节细胞轴突再生作用的比较

目的比较含嗅鞘细胞（OEC）或（和）体外溃变的周围神经移植对成年大鼠视网膜神经节细胞（RGC）轴突再生的影响。方法将24只成年雄性Sprague-Dawley大鼠随机分为4组，每组各6只大鼠：A组（周围神经对照组）：将取出的一段自体坐骨神经与眶内切断的左侧视神经近侧断端吻合；B组（OEC注入周围神经组）：自取出的坐骨神经两端注入10 μl OEC悬液后移植于视神经断端。C组（周围神经体外溃变组）：将取出的坐骨神经在体外单独培养5 d后植于视神经断端；D组（OEC-周围神经共培养组）：将取出的坐骨神经与OEC共培养5d后植于视神经断端。移植术后4周处死动物，计数各组以5%荧光金逆行标记的再生RGC数量。结果B、C、D三组RGC均数1481±268、1235±266和1464±285显著高于A组799±109（P值分别为0.0002、0.0010和0.0003）；B、C、D三组间差异无统计学意义（P值分别为0.3644、0.9167和0.4344）。结论OEC具有促进RGC轴突在新鲜周围神经移植物中再生的作用，但这种作用与体外溃变的周围神经相比无明显差异，二者亦无协同作用。（中华眼底病杂志，2007，23：130-132）     

共培养系统中巨噬细胞对大鼠视网膜神经节细胞存活和轴突再生的影响

目的 观察体外巨噬细胞对视网膜神经节细胞（RGC）存活和生长的影响.方法 采用Transwell小室建立大鼠腹膜腔巨噬细胞和RGC的共培养模型,以不用巨噬细胞共培养的RCC作为对照组,用台盼蓝染色计数及相差显微镜观察RGC存活的时间,并测量培养1 d、3 d和5 d时RGC突起的平均长度,进行组间比较.结果 培养1 d、3 d、5 d和7 d,共培养组平均活细胞数分别为（35.50±2.92）个、（28.20±3.36）个、（18.70±3.95）个和（8.80±1.55）个,对照组为（36.20±2.35）个、（27.10±2.96）个、（15.80±3.04）个和（8.40±2.01）个,两组之间差异均无统计学意义（t=0.369、0.497、0.487、2.854,P均〉0.05）.培养1 d、3 d和5 d,共培养组RGC突起的平均长度分别为（19.79±3.98）μm、（68.30±4.07）μm和（95.51±6.51）μm,明显长于对照组[（15.28±1.28）μm、（58.18±4.22）μm和（82.61±3.75）μm],两组差异均有统计学意义（t=-4.562、-6.554、-7.027,P均〈0.05）.结论 巨噬细胞可明显促进共培养     

血管内皮生长因子B对小鼠视神经保护作用的研究

目的 探讨血管内皮生长因子B(VEGF-B)在视网膜组织的表达及其对视网膜神经节细胞的保护作用.方法 对照实验研究.35只成年雌性健康C57BL/6小鼠,分为正常对照组,视神经损伤后6 h、1 d、1周、2周组.其中10只鼠用于原位杂交,每组2只鼠;25只鼠用于实时定量逆转录聚合酶链反应(real time RT-PCR),每组5只鼠.采用原位杂交法观察实验鼠视网膜组织VEGF-B的mRNA表达;用real time RT-PCR法观察视网膜组织损伤后不同时间VEGF-B的mRNA定量表达;从双侧上丘行荧光金逆行标记和视网膜神经节细胞计数,评估玻璃体腔内注射重组人VEGF-B(450 mg/L)对视网膜神经节细胞的保护作用.应用SAS统计学软件进行数据分析.对组间real timeRT-PCR检测结果比较采用方差分析,对组间视网膜神经节细胞计数的计量资料比较采用秩和检验.以P<0.05作为差异有统计学意义.结果 小鼠视神经损伤后的视网膜组织VEGF-B表达显著增强,损伤后1周达高峰.玻璃体腔内注射重组人VEGF-B蛋白,可显著增加视网膜神经节细胞的存活数量,分别是单纯视神经损伤组和损伤加玻璃体腔内注射的阴性对照组的1.7倍(t=0.1301,P<0.01)和1.9倍(t=0.001,P<0.01).结论 VEGF-B参与小鼠视神经损伤后的修复,并对视网膜神经节细胞有保护作用.(中华眼科杂志,2009,45:38-42)     

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.     

灯盏细辛对大鼠视神经压榨伤后视网膜神经节细胞的保护作用

目的　探讨中草药灯盏细辛对大鼠标定性视神经压榨伤所致的视网膜神经节细胞(RGC)损伤的防护和修复作用。方法　 4 2只健康SD大鼠随机均分为A组和B组。两组均用特制微型视神经夹直接夹持视神经 ,制作成单眼视神经部分压榨伤模型后 ,A组不予任何治疗 ,B组予以灯盏细辛治疗 ,直至处死动物。以上两组按致伤日至处死日动物的存活时间又分为 :A1组和B1组 (损伤后 4d) ,A2 组和B2 组 (损伤后 14d) ,A3 组和B3 组 (损伤后 2 1d) ,每组各 7只大鼠。于处死前 3d双上丘直接注射 3%快蓝标记双眼RGC。处死日行眼球摘除术后 ,将双眼全视网膜组织铺片置于荧光显微镜下 ,在距视乳头 1mm处的颞上、颞下、鼻下及鼻上 4处作荧光摄影 ,并输入计算机经图像分析仪计数RGC。计算RGC标识率 ,即 (损伤眼RGC数 /未损伤眼RGC数 )× 10 0 % ,并进行统计学分析。结果　A组大鼠中 ,A1、A2 及A3 组的RGC标识率分别为 (77 79± 7 11) %、(6 3 76± 3 79) %、(5 4 6 6±4 75 ) % ;B组大鼠中 ,B1、B2 及B3 组的RGC标识率分别为 (80 13± 12 0 3) %、(78 17± 9 19) %及(83 5 9± 12 6 1) %。A2 和A3 组分别与B2 和B3 组比较 ,差异均有非常显著意义 (t=14 10 8,36 2 0 3;P<0 0 1)。结论　大鼠标定性视神经压榨伤后用灯盏细辛治疗 ,     

表没食子儿茶素没食子酸酯对大鼠视神经钳夹伤后视网膜神经节细胞的保护作用

　　目的　观察绿茶提取物表没食子儿茶素没食子酸酯(EGCG)对大鼠视神经钳夹伤视网膜神经节细胞（RGC）是否具有保护作用。方法　72只Wistar大鼠随机分为正常对照组（A组）、假手术+EGCG组（B组）、视神经钳夹+生理盐水组（C组）、视神经钳夹+EGCG组（D组）等4组,每组各18只。B、D组在视神经钳夹或假手术前2 d起给予腹腔注射EGCG  25 mg/（kg·d）,直至手术后2 d,共5 d;随后改为口服2 mg/（kg·d）。C组以生理盐水替代EGCG。每次每组取6只大鼠,采用3%荧光金经上丘逆行标记RGC方法,比较各组视神经钳夹伤后7、14、28 d RGC的存活数量;采用免疫组织化学染色及蛋白免疫印迹方法检测各组视神经组织神经丝蛋白（NF-L）的表达。结果　视神经钳夹伤后7 d,C、D组RGC存活数量分别为（943.61±85.06）、（1 134.45±117.85） 个/mm2;14 d时分别为（812.76±172.07）、（1 021.67±94.02） 个/mm2;28 d时分别为（766.94±171.45）、（1 009.72±126.40）个/mm2。各时间点D组RGC存活数量均显著高于C组（t=3.216,2.609,2.792;P=0.009,0.026,0.019）。各时间点A、B组间RGC存活数量差异无统计学意义（t=0.749,0.403,0.254;P值均＞0.05）;视神经钳夹后7、14、28 d,D组视神经组织NFL表达均高于C组（t=9.847,5.731,2.868;P=0.001,0.005,0.045）。结论　EGCG对大鼠视神经钳夹伤后RGC具有一定的保护作用。      

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.     

大鼠急性视网膜缺血节细胞死亡时脑红蛋白的表达

目的 研究大鼠视网膜急性缺血中视网膜节细胞(RGCs)死亡时脑红蛋白(Nsb)的表达.方法 实验研究.采用特异性结扎大鼠视网膜动脉的方法造成视网膜急性缺血模型,按照结扎时间不同(0、15、30、60 min)分为A、B、C、D组,每组10只大鼠,均以左眼为实验眼.每组随机选取3只大鼠视网膜用于免疫印迹法检测,4只大鼠视网膜做HE染色节细胞计数及免疫组化染色荧光强度分析,3只大鼠做免疫电子显微镜观察.采用单因素方差分析对不同结扎时间Ngb蛋白定量及RGCs数目进行统计学分析,采用KSD-t检验进行两两比较.结果 视网膜完全结扎后,A、B、c、D组Ngb蛋白表达量分别为1.439±0.014、2.023±0.134、1.416±0.030及1.073±0.064;RGCs计数结果分别为4368±124、4296 ±96、4132±104、3973±115,组间比较差异有统计学意义(F=79.548,10.191,P<0.05).B组表达最高,之后逐渐降低,C组接近正常,此时与A组比较RGCs数量开始减少,D组Ngb的表达已明显低于A组,与A组比较RGCs数量进一步减少.在视网膜各层中,Ngb的表达以RGCs层为最高,其次为内丛状层与外丛状层.RGCs中Ngb主要分布在胞质,C组线粒体外室和线粒体嵴也发现有Ngb表达,而内核层及外核层细胞的胞质内始终未见Ngb的表达.结论 Ngb在大鼠RGCs急性缺血死亡时表达快速升高,主要表达于RGCs的胞质内,与RGCs的生存状态关系密切.     

压力对大鼠纯化视网膜神经节细胞存活及轴突生长的影响

目的 研究压力对视网膜神经节细胞(RGC)存活和轴突生长的影响及其与神经微丝蛋白(NF)-H表达变化的关系,探讨压力引起RGC损伤的机制.方法 对照实验研究.纯化培养20只SD乳鼠的RCC.采用开放式压力控制培养系统,建立压力损伤模型,分别检测20、40、60及80 mm Hg(1 mm Hg=0.133 kPa)压力作用48 h对RGC存活数及轴突生长的影响,测定存活且有轴突的RGC数及其最长轴突的长度.采用免疫组织化学染色加图像分析系统,检测压力对RGC表达NF-H的影响,以吸光度(A)值表示.采用SPSS 13.0统计学软件对数据进行分析.组间RGC存活数和细胞轴突长度与对照组比较采用单因素方差分析(One-way ANOVA),组间进一步两两比较采用SNK法(g检验).以P<0.05作为差异有统计学意义.结果 纯化培养的SD大鼠RGC纯度可达96.24%.压力40、60及80 mm Hg作用48 h,RGC存活数和细胞轴突长度与对照组比较明显降低,差异有统计学意义(存活细胞数:P=0.001,0.000,0.000;细胞轴突长度:P=0.000,0.000,0.000),且降低程度随压力增高而增大;NF-H表达差异也有统计学意义(P=0.000,0.000,0.000),且NF-H阳性细胞分布不规则.结论 压力可影响纯化培养的RGC存活数和轴突生长,可能与其下调RGC中NF-H的表达有关,推测压力是引起青光眼视神经损害的机制之一.(中华眼科杂志,2009,45:164-167)     

Differential effects of charybdotoxin on the activity of retinal ganglion cells in the dark- and light-adapted mouse retina

Patch-clamp recordings were made from retinal ganglion cells in the mouse retina. Under dark adaptation, blockage of BK_Ca channels increases the spontaneous excitatory postsynaptic currents (EPSCs) and light-evoked On-EPSCs, while it decreases the light-evoked Off inhibitory postsynaptic currents (IPSCs). However, under light adaptation it decreases the light-evoked On-EPSCs, the spontaneous IPSCs and the light-evoked On- and Off-IPSCs. Blockage of BK_Ca channels significantly altered the outputs of RGCs by changing their light-evoked responses into a bursting pattern and increasing the light-evoked depolarization of the membrane potentials, while it did not significantly change the peak firing rates of light-evoked responses.     

雄激素预处理对实验性变态反应性脑脊髓炎大鼠视神经和视网膜神经节细胞的影响

目的:观察雄激素预处理对实验性变态反应性脑脊髓炎（EAE）大 鼠视神经形态功 能和视网膜神经节细胞(RGC)凋亡的影响。 方法:将雌性Wistar大鼠41只 随机分为正常组10只、未 用药对照组15只和雄激素组16只。正常组和未用药对照组每天以1％乙醇灌胃，雄激素组每 天以0.25 mg/kg甲睾酮灌胃。用药20 d后，未用药对照组和雄激素组注射0.4 ml完全弗 佐剂-豚鼠脊髓匀浆，并辅以注射百日咳疫苗诱导EAE模型。诱导前7 d，大鼠上丘和外侧膝状体 注射荧光金以逆行标记RGC。继续用药至诱导后14～30 d，取正常鼠 和出现症状48～72 h内的未用药对照组和雄激素组大鼠，应用光学显微镜和闪光视觉诱发电 位 （FVEP）观察其视神经形态和功能的变化；荧光显微镜下观察视网膜铺片并计数RGC；原位缺口末端标记法（TUNEL）观察RGC的调亡情况。 结果：诱导10d开始，E AE大鼠相继出现尾及后肢无力，麻痹等症状。与未用药对照组相比，雄激素组的发病潜伏期 延长（P=0.035），症状评分降低（P=0.042）。未用药对照组大鼠视神经纤维走 行纡曲呈波浪状，弥漫脱髓鞘 改变；雄激素组视神经纤维走行较规则，脱髓鞘改变不明显。FVEP显示与未用药对照组相比 ，雄激素组的N₁、P和N₂波潜伏期明显缩短（P＜0.05），N_1^-P和P-N₂振幅提高（P＜0.05）。正常组、未用药对照组和雄激素组RGC数分别为（2284±132）、 （934±78）、（1725±95）个/mm²，雄激素组RGC数较未用药对照组增多（P＝0.028）。正常组、未用药对照组和雄激素组TUNEL阳性细胞数分别为（4.02±0.16）、（24.44±2.22）、（9.84±2.36）个/高倍视野，雄激素组TU NEL阳性细胞数较未用药对照组明显减少（P＝0.025）。 结论:雄激素可降低EAE发病率和症状评分，抑制EAE鼠RGC的凋亡，减轻视神经脱髓鞘改变，改善视神经传导功能。     

超声微泡造影剂联合美金胺增强视神经损伤大鼠视网膜神经节细胞保护作用

目的 探讨超声微泡造影剂联合美金胺对视神经损伤大鼠视网膜神经节细胞( RGC)的保护作用.方法 将Sprague-Dawley(SD)雄性成年大鼠40只随机分为正常对照组(A组),假手术组(B组),空白对照组(C组),玻璃体腔单独注射美金胺组(D组),玻璃体腔注射美金胺加超声微泡组(E组)5个组,每组8只大鼠,再将各组随机分为视神经损伤后1、2周2个亚组,各亚组4只大鼠.A组不做任何处理;B组只暴露视神经,不进行钳夹,玻璃体腔注射生理盐水,立即用超声波辐照大鼠眼球;C～E组建立视神经钳夹伤模型后,处理方式分别为C组玻璃体腔注射生理盐水,D组玻璃体腔注射美金胺,E组玻璃体腔注射超声微泡造影剂及美金胺,立即用超声波辐照大鼠眼球.视神经损伤1、2周时,各组行逆行荧光金标记RGC并计数;闪光视觉诱发电位(F-VEP)检测,记录P100波潜伏期及振幅;荧光电子显微镜下观察视网膜细胞形态学改变.结果 逆行荧光金标记RGC结果显示,各处理组视网膜定向铺片上均可见金黄色着染的RGC.A、B组RGC数间差异无统计学意义(q=0.018,0.011;P=0.986,0.873);C～E组RGC数均较A组减少,差异具有统计学意义(F=85.944,P=0.012);D组RGC数多于C组,差异具有统计学意义(q=1.721,1.924;P=0.043,0.037);E组RGC数明显高于C、D组,差异具有统计学意义(q=1.128,1.482,P=0.027,0.008;q=1.453,1.855,P=0.031,0.010).F-VEP检测发现,A、B组P100波潜伏期及振幅间差异无统计学意义(q=0.008,0.019,P=0.981,0.946;q=0.072,0.052,P=0.737,0.851) ;C～E组P100波潜伏期较A组延长,振幅较A组降低,差异具有统计学意义(F=134.312,106.312;P=0.017,0.009).荧光电子显微镜下观察发现,A、B组大鼠视网膜各层结构完整,排列整齐,RGC排列紧密整齐,细胞核均匀深染,胞核大小一致.C～E组大鼠的视网膜不同程度水肿变厚,RGC有不同程度的排列紊乱,空泡化及细胞数目减少.结论 超声微泡造影剂联合美金胺能抑制视神经损伤后大鼠RGC的丢失,促进其视功能的恢复,对视神经损伤大鼠的RGC具有保护作用.     

超声微泡造影剂介导脑源性神经营养因子联合转染视网膜和视皮质对视神经损伤后视网膜神经节细胞的保护作用

　　目的　观察超声微泡造影剂介导脑源性神经营养因子（BDNF）联合转染大鼠视网膜和视皮质区细胞对视神经损伤后视网膜神经节细胞（RGC）的保护作用。方法　雄性Sprague-Dawley（SD）大鼠88只随机分为正常组（A组）、假手术组（B组）、空白对照组（C组）、单纯眼转染组（D组）、单纯脑转染组（E组）、联合转染组（F组）;A组8只大鼠,B～F组每组16只大鼠。建立钳夹视神经损伤模型,将B～F组大鼠随机分为视神经损伤1、2周亚组,各亚组8只大鼠。B、C组玻璃体腔和视皮质区分别注射磷酸盐缓冲液（PBS）,D、E组玻璃体腔和视皮质区分别注射BDNF质粒（pBDNF）微泡造影剂悬液,F组玻璃体腔和视皮质区同时注射pBDNF微泡造影剂悬液。D～F组注射pBDNF微泡微泡造影剂悬液后,立即用超声辐照相应转染部位。视神经损伤后1、2周,各组行逆行荧光金标记RGC计数;半胱氨酸蛋白酶-3(caspase-3）蛋白免疫组织化学染色,观察其阳性表达情况;图形视网膜电流图（PERG）检测,记录N95振幅。结果　荧光金标记RGC结果显示,各组均可见金黄色荧光散布于视网膜定向铺片上。A~F组间RGC计数差异有统计学意义（F=256.30,P＜0.01）;B~F组视神经损伤1、2周亚组间RGC计数差异也有统计学意义（F=6518,P＜0.01）。光学显微镜观察发现,A、B组大鼠视网膜均未见caspase-3蛋白阳性表达;C~F组均可见主要位于神经节细胞层的caspase-3蛋白阳性表达。PERG检测发现,A~F组间N₉₅振幅差异有统计学意义（F=121.56,P＜0.01）;B~F组视神经损伤1、2周亚组间N95振幅差异也有统计学意义（F=8238,P＜0.01）。结论　超声微泡造影剂介导BDNF联合转染视网膜和视皮质区细胞能抑制视神经损伤后RGC凋亡,提高RGC存活数,保护其视功能。      

OCT测量的黄斑区GCC和视盘RNFL厚度对前部缺血性视神经病变诊断效能的评估

背景 前部缺血性视神经病变(AION)是常见的眼部病变,预后较差,其早期诊断对视力预后至关重要.频域光相干断层扫描(FD-OCT)能在活体实时显示视网膜组织的细微结构,可定量测量黄斑区神经节细胞复合体(GCC)及视盘神经纤维层厚度(RNFL)厚度.以往的研究多用视盘RNFL厚度来评估AION患者视网膜神经节细胞(RGCs)的丢失情况,近期研究显示GCC厚度可检测出AION患者视网膜结构变化,但鲜见视盘RNFL厚度和GCC厚度对AION诊断效能的比较研究. 目的 评估OCT测量的GCC和RNFL对AION的诊断效能.方法 采用诊断试验研究方法,于2013年12月至2014年7月纳入在天津医科大学眼科医院就诊的AION患者15例15眼,同期纳入天津医科大学眼科医院职工及门诊就诊的年龄和性别匹配的正常对照者14人14眼,采用频域OCT测量黄斑区GCC厚度及视盘RNFL厚度,黄斑区GCC厚度测量指标包括黄斑区周围6mm×6mm范围上方、下方GCC厚度和平均GCC厚度,计算局部丢失体积(FLV)和整体丢失体积(GLV);视盘RNFL厚度测量指标包括视盘上方、下方及平均RNFL厚度,比较AION组与正常对照组间检测结果的差异.采用受试者工作特征(ROC)曲线下面积(AUC)评估FD-OCT测量的黄斑区GCC厚度及视盘RNFL厚度对AION的诊断效能.结果 与正常对照组比较,AION组受检眼黄斑区上方、下方及平均GCC厚度均明显薄于正常对照组,差异均有统计学意义(t=-3.402,P=0.002;t 2.690,P=0.012;t=2.913,P=0.007);AION组受检眼FLV值和GLV值分别为(8.39±4.54) μm3和(19.57±10.66) μm3,明显低于正常对照组的(0.64±0.48) μm3和(1.14±0.91) μm3,差异均有统计学意义(t=5.036、6.723,均P＜0.01).AION组受检眼视盘上方、下方及平均RNFL厚度较正常对照组均明显变薄,差异均有统计学意义(t=2.815,P=0.009;t=2.392,P=0.024;t=2.863,P=0.008).AION眼测量的FLV和GLV的AUC值均为1.000,黄斑区上方、平均GCC厚度及下方GCC厚度AUC依次为0.871、0.819和0.795,视盘平均RNFL厚度及视盘上方、下方RNFL厚度AUC依次为0.814、0.809和0.762. 结论 OCT测量的GCC厚度和RNFL厚度在AION诊断能力中具有可比性,FLV和GLV在AION患者的神经节细胞层检测方面能力较强,黄斑区GCC厚度与RNFL厚度测量在AION的诊断中可互为补充.     

PTEN/SOCS3缺失对视神经损伤大鼠视网膜神经节细胞存活和轴突再生的影响

目的　探讨磷酸酶-张力蛋白同源物(PTEN)和细胞因子信号转导抑制蛋白3(SOCS3)缺失对视神经损伤大鼠视网膜神经节细胞（RGCs）存活和轴突再生的影响。方法　将Thy1-YFP/PTEN^F/FSOCS3^F/F大鼠作为对照组,玻璃体内注射腺相关病毒（AAV）介导PTEN基因缺失的Thy1-YFP/PTEN^F/F大鼠为PTEN^-/-组;玻璃体内注射AAV介导SOCS3基因缺失的Thy1-YFP/SOCS3^F/F大鼠为SOCS3^-/-组;玻璃体内注射AAV介导PTEN基因和SOCS3基因均缺失的Thy1-YFP/PTEN^F/F SOCS3^F/F大鼠为PTEN^-/-SOCS3^-/-组,每组各20只。HE染色观察各组大鼠视网膜组织病理学形态,免疫荧光染色鉴定各组大鼠RGCs存活情况,流式细胞仪检测各组大鼠RGCs凋亡情况,并对比轴突再生数量;利用Western blot检测各组大鼠RGCs中GFAP和GAP-43的蛋白相对表达水平。结果　对照组大鼠视网膜细胞炎症反应明显,细胞间层次结构混乱、连接差,分散性强;PTEN^-/-组和SOCS3^-/-组大鼠视网膜整体结构较规则,层次较清晰,炎症反应有所减轻;PTEN^-/-SOCS3^-/-组大鼠视网膜结构清晰,较规则,细胞之间连接紧密,炎症反应明显减轻。PTEN^-/-组和SOCS^-/-组大鼠RGCs存活率均显著高于对照组（均为P<0.001）。PTEN^-/-SOCS3^-/-组大鼠RGCs存活率均明显高于PTEN^-/-组和SOCS3^-/-组（均为P<0.001）。PTEN^-/-组和SOCS3^-/-组大鼠RGCs凋亡率显著低于对照组（均为P<0.001）,PTEN^-/- SOCS3^-/-组大鼠RGCs凋亡率均明显低于PTEN^-/-组和SOCS3^-/-组（均为P<0.001）。PTEN^-/-组和SOCS3^-/-组大鼠视神经轴突数目均显著多于对照组（均为P<0.001）,PTEN^-/-SOCS3^-/-组大鼠视神经轴突数目均明显多于PTEN^-/-组和SOCS3^-/-组（均为P<0.001）。PTEN^-/-组和SOCS3^-/-组大鼠RGCs中GFAP和GAP-43蛋白表达均显著低于对照组（均为P<0.001）,PTEN^-/-SOCS3^-/-组大鼠RGCs中GFAP和GAP-43蛋白表达均明显低于PTEN^-/-组和SOCS3^-/-组（均为P<0.001）。结论　PTEN和SOCS3基因缺失与视神经损伤大鼠RGCs存活和轴突再生具有一定的关系,不仅能够促进RGCs的增殖,抑制其凋亡,还能够促进视神经轴突再生,同时敲减PTEN和SOCS3基因最为显著。     

Periocular injection of in situ hydrogels containing Leu-Ile, an inducer for neurotrophic factors, promotes retinal ganglion cell survival after optic nerve injury

Intraocular administration of neurotrophic factors has been shown to delay irreversible degeneration of retinal ganglion cells (RGCs). It would be beneficial for the treatment of optic nerve (ON) injury if such neurotrophic factors could be delivered in a less-invasive manner. The dipeptide leucine–isoleucine (Leu–Ile) appears to induce the production of neurotrophic factors, including brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), in the brain. We therefore administered Leu–Ile via periocular depot injection in rats and investigated the dipeptide’s ability to induce BDNF and GDNF in the retina and to delay RGC loss in an ON injury model. Poloxamer–alginate hydrogels containing Leu–Ile were injected into the subconjunctival space of intact or ON-injured rats. BDNF and GDNF levels in the retina were determined by an enzyme immunoassay. Survival of RGCs was assessed in retinal flatmounts. Activation of extracellular signal-regulated kinases (ERK) and cAMP response element binding protein (CREB) in the retina was examined by Western blotting. At 2 h after injection of fluorescein isothiocyanate-conjugated Leu–Ile, the fluorescence intensities in the retina were 4.3-fold higher than those in the saline control. Treatment with Leu–Ile significantly increased the retinal levels of BDNF at 6 h and GDNF at 6–72 h after injection. Treatment with Leu–Ile significantly increased RGC survival to 14 days after ON injury and enhanced the activation of ERK at 72 h and CREB at 48 h after injection in the ON-injured retina. These results suggest that periocular delivery of Leu–Ile induces BDNF and GDNF production in the retina, which may eventually enhance RGC survival after ON injury.     

Neuroprotective effects of tempol on retinal ganglion cells in a partial optic nerve crush rat model with and without iron load

Iron overload can contribute to oxidative stress in many tissues. We studied the effects of pretreatment with iron dextran on RGC loss in a calibrated partial optic nerve crush (PONC) model in rats, along with the protection offered by tempol (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl, a membrane-permeable superoxide dismutase mimetic and free-radical scavenger), in the same experimental paradigm. A total of 40 rats in 6 groups of 5-8 animals each underwent PONC in one eye and sham crush in the other. Animals were pretreated with a single iron dextran load 24 h prior to PONC, and treated with tempol 6 h before and then once daily after PONC. Control animals were treated with PBS. RGC were retrogradely labeled with a fluorescent marker; all data are expressed in percent of the RGC count in the respective sham-treated eye. Immunohistochemistry was performed to visualize 3-nitrotyrosine, a marker of nitroxidative stress. PONC without iron pretreatment resulted in the survival of only 31.4% of labeled RGC after 7 days. Even fewer RGC (12.7%) survived after PONC with iron pretreatment. However, tempol in doses of 20 mg/kg of body weight (BW) significantly attenuated this effect when given as described above; in the group without iron pretreatment the number of surviving RGC doubled from 31.4% to 62.1%. In the group with iron pretreatment the survival rate of RGC increased even more pronouncedly, from 12.7% without tempol to 46.2% with tempol. Tempol in doses of 1 mg/kg BW and 5 mg/kg BW showed no significant rescue of RGC. Immunostaining showed nitrotyrosine-positive RGCs in PONC but not in sham-treated eyes and an increase in positive cells after iron load. Tempol treatment reduced nitrotyrosine staining in both the iron and non-iron groups. Our results demonstrate that PONC results in significantly greater RGC damage when iron pretreatment is performed, and that the compound tempol may provide additional protection for RGC in cases of neuronal damage both with and without prior iron treatment.