塞来昔布-聚乳酸-羟基醋酸共聚物微球的缓释性及其对实验性脉络膜新生血管抑制作用的在体研究

背景 脉络膜新生血管(CNV)是多种眼底病变共同的病理基础,虽然以往有多种方法进行治疗,但均有其缺点.研究表明,塞来昔布可以治疗实验性CNV,而寻求塞来昔布新的剂型和给药途径可为临床上研发治疗CNV疾病的缓释药物提供依据. 目的 评价体外释放实验中塞来昔布-聚乳酸-羟基醋酸共聚物微球(CEL-PLGA-MS)的缓释性能及其玻璃体腔注射后对实验性CNV的抑制作用. 方法 采用扫描电子显微镜观察CEL-PLGA-MS的形态,用激光粒度分析仪测量其粒径,应用高效液相色谱法(HPLC)测定其载药量及体外释放情况.选取72只雄性棕色挪威(BN)大鼠,用氪激光光凝法建立大鼠右眼CNV模型,将模型眼按照随机数字表法随机分为CEL-PLGA-MS组、塞来昔布组、空白PLGA组和PBS组,每组9只大鼠.根据分组的不同,大鼠玻璃体腔分别注射8μl含塞来昔布320 μmol/L PLGA微球、80 μmol/L塞来昔布、空白PLGA微球及0.01 moL/L PBS.于玻璃体腔注射后14 d,采用荧光素眼底血管造影(FFA)法观察各组大鼠CNV生成情况,OCT测量各组视网膜脉络膜纤维血管增生(FVP)厚度,制备视网膜色素上皮(RPE)-脉络膜-巩膜复合物标本,光学显微镜下观察各组大鼠FVP的形态结构.分别于玻璃体腔注射后7d、28 d,采用逆转录PCR (RT-PCR)法测定并比较各组大鼠激光斑区域血管内皮生长因子(VEGF)mRNA和环氧合酶2(COX-2)mRNA的相对表达量(RQ).结果 CEL-PLGA-MS的平均粒径为2 467.9 nm,平均载药量为7.77％,体外释放可持续45 d,累积释放百分率为80.91％.玻璃体腔注射后CEL-PLGA-MS在玻璃体中呈团状.注射后14d,OCT测量显示空白PLGA组、PBS组、塞来昔布组和CEL-PLGA-MS组平均FVP厚度值分别为(94.67±4.64)、(98.56±4.72)、(71.00±4.77)、(50.44±.3.01) μm,其中空白PLGA组和PBS组大鼠平均FVP厚度值均明显高于CEL-PLGA-MS组和塞来昔布组,差异均有统计学意义(均P＜0.01),CEL-PLGA-MS组平均FVP厚度值明显低于塞来昔布组,差异有统计学意义(P＜0.01).FFA晚期可见空白PLGA组和PBS组视网膜光凝斑区大量荧光素渗漏,呈强荧光,而塞来昔布组和CEL-PLGA-MS组荧光素渗漏量少.光学显微镜下视网膜光凝区中空白PLGA组和PBS组纤维血管组织较塞来昔布组和CEL-PLGA-MS组厚.玻璃体腔注射后7d及28 d空白PLGA组大鼠RPE-脉络膜-巩膜标本中COX-2 mRNA和VEGF mRNA的RQ值均明显高于塞来昔布组和CEL-PLGA-MS组,差异均有统计学意义(均P＜0.01);玻璃体腔注射后7d塞来昔布组大鼠RPE-脉络膜-巩膜标本中COX-2 mRNA RQ值明显低于CEL-PLGA-MS组,而注射后28 d塞来昔布组COX-2 mRNA和VEGFmRNA RQ值均明显高于CEL-PLGA-MS组,差异均有统计学意义(均P＜0.01). 结论 CEL-PLGA-MS形态规则,粒径均匀,体外实验有良好的缓释效果;大鼠玻璃体注射CEL-PLGA-MS后能抑制实验性CNV,其抑制作用较塞来昔布更持久.     

人脐血干细胞玻璃体腔移植对大鼠外伤性视神经损伤的保护作用

目的观察人脐血干细胞(human umbilical cord blood stem cells,h UCBSC)移植对视神经部分受损SD大鼠视网膜神经节细胞(retinal ganglion cells,RGC)的保护作用。方法将48只健康成年SD大鼠随机分为2组,2组SD大鼠暴露视神经,应用40 g夹持力的视神经夹在大鼠眼球后2 mm处夹视神经30 s造成部分视神经损伤模型,均损伤左眼。A组:伤后1周玻璃体腔注射脐血干细胞载体PBS,24只。B组:伤后1周玻璃体腔注射h UCBSC,24只;2组均于注射后7 d、14 d、21 d、28 d处死动物。处死前7 d双上丘注射50 g·L-1荧光金逆行标记双眼RGC。然后按时间先后处死大鼠分离视网膜置于荧光显微镜下,计数2组RGC并计算RGC标识率。结果 A、B两组视神经损伤眼RGC计数均低于未损伤眼(均为P<0.05),且随时间延长两组RGC标识率均呈下降趋势(均为P<0.05),但B组注射后7 d、14 d、21 d、28 d RGC标识率(77.52±6.33)%、(74.12±8.23)%、(64.78±5.21)%、(59.93±9.00)%下降幅度明显较A组(75.68±8.74)%、(68.21±10.59)%、(56.24±9.34)%、(48.91±8.81)%平缓。同时间段B组RGC标识率均高于A组,且差异均有统计学意义(均为P<0.05)。结论玻璃体腔注射h UCBSC可减缓外伤性视神经损伤大鼠视网膜中RGC的凋亡,对RGC具有一定的保护作用。     

局部应用尿激酶对大鼠血-视网膜屏障外向通透性的影响

背景 视网膜血管再通是治疗视网膜血管阻塞性疾病的关键.研究证实,玻璃体腔注射尿激酶可抑制视网膜毛细血管内皮细胞间紧密连接复合体中Occludin蛋白的表达. 目的 用伊文思蓝(EB)玻璃体注射法观察尿激酶眼局部注射后大鼠血-视网膜屏障(BRB)外向通透性的变化. 方法 采用随机数字表法将60只SD大鼠随机分为4个组,各组大鼠均以右眼作为实验眼.尿激酶玻璃体注射组大鼠将尿激酶350 U(商品单位)4μl注入右眼玻璃体腔,同容积的PBS以同样方式注射作为PBS玻璃体注射组,尿激酶球后注射组大鼠将10μl 1000U尿激酶注入右眼球后组织,等容积的PBS以同样方式注射作为PBS球后注射组.上述药物注射后24 h,所有大鼠右眼玻璃体腔注射质量分数0.5％ EB 4μl.EB注射后4h摘取大鼠右侧眼球,完整取出玻璃体并以甲酰胺温浴萃取EB.所得提取液以甲酰胺-分光光度法检测EB的质量浓度,并据此推算大鼠玻璃体腔内EB的质量浓度,对各组间大鼠玻璃体中EB质量浓度进行比较. 结果 尿激酶玻璃体注射组大鼠玻璃体呈淡蓝色反光,眼科手术显微镜下可见视网膜血管;尿激酶球后注射组大鼠玻璃体呈蓝色,眼底血管不易显示,而PBS玻璃体注射组和PBS球后注射组大鼠玻璃体均呈深蓝色反光,眼底无法窥见.尿激酶玻璃体注射组、PBS玻璃体注射组、尿激酶球后注射组和PBS球后注射组大鼠玻璃体的甲酰胺EB溶液吸光度(A)值分别为0.181±0.008、0.450±0.017、0.330±0.009和0.436±0.012;尿激酶玻璃体注射组大鼠玻璃体腔内EB的质量浓度为(0.266±0.014)g/L,明显低于PBS玻璃体注射组、尿激酶球后注射组和PBS球后注射组的(0.667±0.026)、(0.496±0.015)和(0.657±0.017)g/L,4个组间差异有统计学意义(F=100.406,P＜0.01),其中尿激酶玻璃体注射组大鼠玻璃体EB质量浓度均明显低于其他3个组,差异均有统计学意义(均P＜0.01).结论 大鼠眼局部应用尿激酶可增加BRB的外向通透性,玻璃体腔内注射EB是检测大鼠BRB外向通透性的可靠方法.     

视网膜脱离模型中外源性促红细胞生成素对其受体表达的影响

目的探讨外源性促红细胞生成素（EPO）对促红细胞生成素受体（EPOR）在脱离的视网膜中表达的影响。方法通过视网膜下腔注射质量分数1.4%透明质酸钠在60只SD大鼠的右眼建立视网膜脱离（RD）模型,12只正常SD大鼠为正常对照组。不同组RD模型眼（每组12只眼）玻璃体腔内分别注射PBS或100、200、400ng重组大鼠源性EPO。玻璃体注射后3d应用Westernblot法半定量检测各组SD大鼠脱离的视网膜中EPOR蛋白表达水平的变化并进行比较,应用免疫组织化学法定位检测脱离的视网膜中EPOR蛋白的表达。结果 Westernblot检测结果表明大鼠正常视网膜中EPOR表达量少,为0.28±0.02;造模后3d,EPOR在脱离的视网膜中表达量明显增加,为0.41±0.05,差异有统计学意义（P〈0.05）。RD＋PBS组、RD＋EPO100ng组、RD＋EPO200ng组和RD＋EPO400ng组EPOR蛋白的表达量分别为0.39±0.03、0.41±0.03、0.43±0.07、0.44±0.05,明显高于对照组,差异均有统计学意义（P〈0.05）,但RD＋PBS组、RD＋EPO100ng组、RD＋EPO200ng组和RD＋EPO400ng组间EPOR蛋白的表达差异均无统计学意义（P〉0.05）。RD组与RD＋不同剂量EPO组比较EPOR表达的差异无统计学意义（P〉0.05）。免疫组织化学检测结果证实EPOR蛋白表达于视网膜各层,RD＋不同剂量的EPO处理组EPOR表达均强于正常对照组。结论 RD发生后补充外源性EPO对EPOR的表达并无影响。     

超声微泡造影剂促进重组腺相关病毒载体介导基因转染视网膜神经节细胞的体内实验

目的 观察超声微泡造影剂提高重组腺相关病毒(rAAV2)介导增强型绿色荧光蛋白(EGFP)基因在体内转染视网膜神经节细胞(RGC)的效率.方法 Sprague-Dawley大鼠40只,随机分为A、B、C、D 4组,每组各10只大鼠.A组玻璃体腔注射磷酸盐缓冲液(PBS)5μl;B组玻璃体腔注射rAAV2-EGFP 5 μl;C组玻璃体腔注射rAAV2-EGFP 5 μl后立即用超声波辐照眼球;D组玻璃体腔注射rAAV2-EGFP和微泡造影剂的混悬液5 μl后立即用超声辐照眼球.玻璃体腔注射21 d后,3%荧光金逆行标记RGC.逆行标记7 d后取出眼球,制作视网膜铺片及视网膜冰冻切片,在激光共聚焦显微镜下观察并计算EGFP基因在RGC的转染率及在RGC表达的平均吸光度[A,旧称光密度(OD)]值;用RGC计数判断损伤情况.结果 荧光金标记RGC后,B、C、D 3组均可观察到RGC中有EGFP表达.其中,D组平均A值为95.02±7.25,RGC转染率为(20.10±0.74)%、均明显高于B、C组,差异有统计学意义(F平均A值=25.970,F转染率=25.799;P<0.01);A、B、C、D组RGC计数差异无统计学意义(F=0.877,P>0.05).结论 在低频和一定能量的超声和微泡造影剂作用下,rAAV2介导EGFP基因转染体内RGC的效率能够安全、有效地提高.     

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。      

内源性促红细胞生成素对大鼠脱离视网膜光感受器细胞的保护作用

背景促红细胞生成素（EPO）对多种视网膜疾病模型中视网膜神经元具有一定的保护作用,但EPO对视网膜脱离（RD）后光感受器细胞是否具有保护作用尚不清楚。目的探讨内源性EPO对RD状态下光感受器细胞的保护作用及可能机制。方法利用视网膜下腔注射质量分数1．4％透明质酸钠建立大鼠RD模型,按每组情况各组玻璃体腔内分别单次注射PBS或不同剂量的外源性可溶性EPO受体（EPOsR）,采用计算机产生随机数字法将72只SD大鼠随机平均分为正常对照组、RD组、RD＋PBS组、RD＋EPOsR2、20、200ng组。分别于造模后3d和14d用过量麻醉法处死大鼠并获得大鼠视网膜标本,采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法检测光感受器细胞的凋亡情况,并分别采用Westernblot和免疫荧光法检测视网膜中caspase-3的活性,RD造模后14d进行组织病理学检查并测量外核层（ONL）厚度。结果RD造模后3d,RD组ONL出现凋亡细胞核,玻璃体腔注射EPOsR组光感受器细胞凋亡进一步增加,随着玻璃体腔注射EPOsR的剂量增加,ONL凋亡细胞核有增加趋势。Westernblot和免疫荧光检测结果均显示,各组视网膜caspase-3表达的条带灰度值分别为（0．15±0．04）、（0．49±0．03）、（0．50±0．07）、（0．63±O．03）、（0．69±0．04）、（0．83±0．04）,各组的总体差异有统计学意义（F=76．016,P=0．000）,RD＋EPOsR200ng组的caspase-3活性均强于其他各组,差异均有统计学意义（P〈0．01）。RD造模后14d,正常对照组、RD组、RD＋PBS组、RD＋EPOsR2、20、200ng组的ONL厚度分别为（47．39±3．39）、（33．96±3．54）、（31．83±5．21）、（31．40±2．63）、（24．99±2．06）、（19．30e3．71）μm,总体差异有统计学意义（F=44．733;P=0．000）;EPOsR处理组ONL厚度明显薄于单纯RD组和RD＋PBS组,差异均有统计学意义（P〈0．05）。结论RD状态下,EPOsR通过剂量依赖的方式诱导视网膜细胞的凋亡和caspase-3活性增强,而缺氧状态下视网膜神经上皮的内源性EPO表达增强可通讨抑制casDase-3活性和抗凋亡作用发挥对光感受器细胞的保护作用。     

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.     

CNTF和Ad-BDNF对视神经夹伤后视网膜神经节细胞存活的影响

目的:观察大鼠视神经夹伤后玻璃体腔内注射睫状神经营养因子(CNTF)和腺病毒介导脑源性神经营养因子(Ad-BDNF)对视神经损伤后视网膜神经节细胞(RGC)存活的影响。方法:制作大鼠视神经定量夹伤模型,玻璃体腔内注射CNTF和Ad-BDNF,经上丘荧光金(FG)逆行标记RGC,计数视网膜铺片上的RGC并行统计学分析。结果:正常SD大鼠视网膜上RGC密度为2155±265个/mm2(n=12),视神经夹伤后RGC在1~2wk内下降速率最快,到3,4wk时RGC细胞数量虽仍有减少但下降速度已经明显减慢。CNTF组在视神经夹伤后1wk时视网膜RGC数显著高于对照组,但2~4wk的结果和对照组比较差异不明显。Ad-BDNF组视神经夹伤后1~4wk视网膜RGC数均显著高于对照组。结论:CNTF治疗组玻璃体腔内一次性注射CNTF可以在损伤早期2wk内为损伤的RGC提供神经营养因子,减少RGC的早期死亡。Ad-BDNF治疗组的这种保护作用可以持续到损伤后4wk,能够为RGC提供长时间地营养支持,但这种作用比较局限,可能与单一营养因子作用有关。     

苦参碱聚乳酸微球玻璃体腔内注射的药代动力学研究

目的研究苦参碱聚乳酸微球玻璃体腔注射后的药代动力学特点。方法将30只新西兰白兔随机分为10组,每组3只兔（6只眼）。除空白组外,其余各组每只眼玻璃体腔均注入苦参碱聚乳酸微球（含苦参碱4 mg）。分别在注药后10 min,2 h,1、3、7、14、21、28、35 d各处死1组动物取双侧眼球并制备玻璃体样本。应用高效液相色谱法检测玻璃体腔药物质量浓度,用DAS软件计算主要的药代动力学参数。结果玻璃体腔注入苦参碱聚乳酸微球（含苦参碱4 mg）后,药物在玻璃体内的平均滞留时间MRT=（221.64±9.70）h,半衰期t1/2=（173.77±32.33）h。缓释微球在玻璃体腔释药可达35 d以上,35 d时药物质量浓度为（121.8±34.6）μg/mL。随时间延长,药物的总体清除率稳定增加。结论玻璃体腔注入苦参碱聚乳酸微球（含苦参碱4 mg）,药物在眼内清除较慢,清除时间明显延长,在玻璃体腔内能够长时间维持较高的质量浓度,表现出良好的体内缓释性。     

Effects of Erythropoietin-Dextran Microparticle-Based PLGA/PLA Microspheres on RGCs

Purpose. We explored the neuroprotective effects of erythropoietin (EPO)-loaded dextran microparticle-based Poly(DL-lactide-co-glycolide)/Poly(DL-lactide) (PLGA/PLA) microspheres (EPO-dextran PLGA/PLA microspheres) on retinal ganglion cells (RGCs) in optic nerve crush rats for a prolonged period of time. Methods. EPO-dextran PLGA/PLA microspheres were prepared first by a novel solid-in-oil-in-water (S/O/W) technique. Then, the in vitro EPO release profile was assessed. Afterward, the bioactive effect of EPO released from EPO-dextran PLGA/PLA microspheres was explored in vitro on the retinal explants. Lastly, the neuroprotective effects of EPO-dextran PLGA/PLA microspheres on RGCs were evaluated in optic nerve crush rats with TUNEL staining for apoptotic RGCs. The level of glial fibrillary acidic protein (GFAP) expressed in retina was explored by immunohistochemistry staining. Survival RGCs were observed by DiI retrograde labeling using a DiI fluorescent tracer (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate). Results. The results demonstrated that a sustained release of EPO from PLGA/PLA microspheres could last for at least 60 days. EPO released from the microspheres showed as efficaciously neuroregenerative as EPO protein solution on retinal explants (P = 0.2554 for neurite density, P = 0.1004 for neurite length). TUNEL staining revealed that EPO-dextran PLGA/PLA microspheres remarkably reduced RGCs death when compared to the control (untreated) group (P < 0.01 at five days and one week post-crush, P < 0.05 at two weeks post-crush). Increased GFAP expression in retina was reduced greatly in EPO-dextran PLGA/PLA microspheres-administrated rats two weeks post optic nerve crush. DiI retrograde labeling revealed that a single injection of EPO-dextran PLGA/PLA microspheres significantly promoted RGCs survival (P < 0.01 at four and eight weeks post-crush). Conclusions. A single intravitreal injection of EPO-dextran PLGA/PLA microspheres appeared to have a prolonged protective effect on RGCs in optic nerve crush rats. The PLGA/PLA microspheres may be a feasible protein delivery system, such as EPO, to intravitreal injection for retinal degeneration diseases.     

静脉注射α-晶体蛋白对视网膜神经节细胞的保护作用及对重要脏器的影响

目的 观察静脉注射α-晶体蛋白对Long Evans大鼠视神经损伤后视网膜神经节细胞(RGC)存活的保护作用及对重要脏器的影响.方法 23只Long Evans大鼠用于本实验.荧光金经双侧上丘及外侧膝状体逆行标记RGC,7 d后制作视神经钳夹伤模型.3只作为正常对照组,其余20只随机分为生理盐水对照组以及1×10-2g/L、1×10-1 g/L、1 g/Lα-晶体蛋白组,每组5只大鼠.视神经钳夹伤后经尾静脉分别注射1.25 ml的等渗生理盐水及3个浓度的α-晶体蛋白,每2天重复注射1次,共7次.2周后对实验大鼠行RGC计数,并对肝、肾、脑、脾、肺等脏器进行病理观察.结果 正常对照组RGC计数(2074±150)个/mm2,视神经钳夹伤后2周时RGC计数,生理盐水对照组(85±15)个/mm2,1×10-2g/L α-晶体蛋白组(124±26)个/mm2,1×10-1g/L α-晶体蛋白组(128±31)个/mm2,1 g/Lα-晶体蛋白组(164±20)个/mm2.正常对照组RGC计数显著高于其他组,3个浓度α-晶体蛋白组存活的RGC数均显著高于生理盐水对照组(F=18.660,P＜0.01).各组肝、肾、脑、脾、肺病理观察未见充血、肿大、炎症等病理改变.结论 静脉注射α-晶体蛋白对视神经损伤后RGC存活具有一定保护作用,所用α-晶体蛋白浓度对重要脏器无病理性影响.

Abstract：

Objective To investigate the effects of intravenous injection of α-crystallin on retinal ganglion cells (RGC) and some important organs of the Long Evans rats. Methods RGC were retrogradelabeled by fluorogold through bilateral superior colliculus and lateral geniculate body for seven days before optic nerve crush injury. Twenty-three Long Evans rats were used for this study, including three rats of normal control group and 20 rats of experimental group. Twenty rats were randomly divided into saline control group and three α-crystallin injection groups, which received tail vein injection of 1.25 ml isotonic saline and three different concentrations (1 × 10-2 , 1 × 10-1 and 1 g/L) of α-crystallin respectively, once every two days and totally seven times. After two weeks, the labeled RGC were counted, and the pathological changes on liver, kidney, brain, spleen and the lungs were investigated. Results Compared with the normal control group, although the number of RGC markedly decreased after two weeks of optic nerve crush injury in every group, the number of RGC in α-crystallin-treated groups was more than those in the saline control group. There were 2074± 150 RGC per mm2 in normal control group, 85 ± 15 RGC per mm2 in saline control group, 124±26 RGC per mm2 in 1 × 10-2 g/L α-crystallin group, 128± 31 RGC per mm2 in 1 × 10-1 g/L α-crystallin group, 164 ± 20 RGC per mm2 in 1 g/L α-crystallin group (F= 18. 660,P＜0. 01). No congestion, swelling, inflammation and other pathological changes were found in liver,kidney, brain, spleen and lung. Conclusions Intravenous injection of α-crystallin protein has protective effects on RGC after the optic nerve crush injury, and no significant effects on important organs.     

Colivelin对视神经保护作用的初步研究

目的初步探讨Colivelin对大鼠外伤性视神经损伤后的神经保护作用和机理,及其保护效果是否具有剂量依赖性。方法 40只健康2月龄Wistar大鼠,随机分为模型组、安慰剂组及Colivelin低剂量组(10-6 μmol·L-1 Colivelin)、Colivelin中剂量组(10-4μmol·L-1Colivelin)、Colivelin高剂量组(10-2 μmol·L-1 Colivelin),每组8只。40只大鼠均做单侧视神经损伤模型,模型组另一侧未做任何处理的8眼为空白对照组。应用无创血管夹建立大鼠视神经夹伤模型,造模后30 min Colivelin治疗组玻璃体内分别注射不同浓度Colivelin 5 μL,安慰剂组注射5μLPBS缓冲液,模型组和空白对照组不给予任何治疗。注药后7d,通过视网膜切片技术,进行HE染色观察视网膜神经节细胞(retinal ganglion cell,RGC)的形态及数目,TUNEL染色法检测RGC的凋亡以及免疫组织化学法检测视网膜中caspase-3的表达。结果 HE染色可见空白对照组视网膜各层细胞排列整齐密集,模型组、安慰剂组、Colivelin治疗组均可见部分RGC核固缩,但随着Colivelin注射浓度的增加,RGC发生核固缩的数量减少。RGC计数:空白对照组每400倍光镜视野下RGC数量为25.750±1.264,模型组为8.236±1.239,安慰剂组为8.514±1.222,Colivelin低剂量组为14.500±1.021,Colivelin中剂量组为16.250±1.319,Colivelin高剂量组为18.097±1.323,除模型组与安慰剂组之间差异无统计学意义(P>0.05)外,其他各组之间差异均有统计学意义(均为P<0.05)。TUNEL染色:模型组和安慰剂组注药后7 d TUNEL染色可见大量凋亡细胞,Colivelin治疗组凋亡细胞数量随Colivelin注射浓度的增加依次递减。RGC细胞凋亡率:模型组为(60.928±2.961)%,安慰剂组为(61.446±2.755)%,Colivelin低剂量组为(58.432±2.835)%,Colivelin中剂量组为(51.948±2.802)%,Colivelin高剂量组为(47.656±2.331)%。Caspase-3表达:模型组、安慰剂组及Colivelin低剂量组、中剂量组、高剂量组均可见caspase-3表达。平均光密度值显示,模型组和安慰剂组相比caspase-3表达无明显差异(分别为0.482±0.012和0.486±0.012),均高于Colivelin治疗组(均为P<0.05),并且Colivelin低剂量组、中剂量组、高剂量组组间差异亦均有统计学意义(分别为0.411±0.017、0.326±0.018、0.234±0.016;均为P<0.05)。结论 Colivelin能有效增加视神经损伤后RGC的数量,抑制其凋亡,减少caspase-3表达,且这一作用呈剂量依赖性。     

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)     

Anti-apoptotic effects of human granulocyte colony-stimulating factor (G-CSF) on retinal ganglion cells after optic nerve crush are PI3K/AKT-dependent

The purpose of present study is to dissect the role of PI3K/AKT signaling in the anti-apoptotic effects of human granulocyte colony-stimulating factor (G-CSF) on rat retinal ganglion cells (RGCs) after optic nerve (ON) crush. The ONs of seventy-two adult male Wistar rats were crushed by a standardized method. Control eyes received a sham operation. G-CSF or phosphate-buffered saline (PBS) was immediately administrated after the ON event for 5 days. Twelve rats were used to investigate the signaling pathways using western blot analysis. In other sixty rats, each eye also received intravitreal injections of PI3K/AKT inhibitor (LY294002) or PBS immediately after the experiments. Rats were euthanized at 1 or 2 weeks after the experiment. RGC density was counted by retrograde labeling with Fluorogold. Western blot analysis of p-AKT, TUNEL assays, and immunohistochemistry of the retinas were conducted. Two weeks after ON injury, RGC densities in the central and mid-peripheral retinas of ON-crushed, G-CSF treated rats were significantly higher than those of corresponding ON-crushed, G-CSF-treated and LY294002-injected rats (survival rates of 60% vs. 39% and 43% vs. 33%, respectively; p < 0.01). Decreased TUNEL staining and the up-regulations of p-AKT signaling in retinas of ON-crushed, G-CSF-treated rats were blocked by intravitreal injections of LY294002. The double staining showed that p-AKT expression co-localized with RGCs in the ON crushed, G-CSF treated retinas. In conclusion, the anti-apoptotic effects of G-CSF on RGCs are PI3K/AKT signaling dependent in the retinas to rescue RGCs after ON crush injury.     

Tracking retinal microgliosis in models of retinal ganglion cell damage

Purpose. To investigate the longitudinal profiles of microgliosis after optic nerve injury induced by optic nerve crush and acute elevation of intraocular pressure (IOP). Methods. A confocal scanning laser ophthalmoscope was used to image the retinal microglia of the CX3CR1(GFP/+) transgenic mice in vivo at baseline, 3 days and then weekly for 4 weeks after optic nerve crush (n = 3), and after elevating the IOP to 110 mm Hg for 30 (n = 3) or 60 (n = 3) minutes. Results. After optic nerve crush, the density of microglia increased by 2.43 ± 0.19-fold at week 1 and then gradually declined with 2.04 ± 0.24-, 1.69 ± 0.25-, and 1.29 ± 0.11-fold increases at week 2, 3, and 4, respectively. Microgliosis followed a similar pattern after acute IOP elevation and the increase in microglia was associated with the duration of IOP elevation. There were 1.35 ± 0.17- and 2.03 ± 0.08-fold increases in microglia at week 1, and 1.15 ± 0.11- and 1.11 ± 0.10-fold increases at week 4, after 30 and 60 minutes of acute IOP elevation, respectively. The morphology of microglia changed from ramified to ameboid form in 1 week, and then returned to ramified form in the subsequent weeks. There was a significant negative association between the number of surviving retinal ganglion cells (RGCs) and the extent of microgliosis during the follow-up period (R(2) = 0.72, P = 0.004). Conclusions. Longitudinal in vivo imaging of the retinal microglia can provide an effective approach to study microgliosis and its association with RGC degeneration.     

胰高血糖素类肽-1缓释珠对大鼠视网膜神经节细胞的保护作用

目的探讨玻璃体内植入胰高血糖素类肽-1（GLP-1）缓释珠对大鼠视网膜神经节细胞的保护作用。设计实验研究。研究对象SPF级Sprague-Dawley（SD）雄性大鼠25只。方法将25只大鼠随机分为2组,实验组13只,对照组12只。实验组大鼠右眼玻璃体内植入4个GLP-1缓释珠,对照组右眼玻璃体内注入4μl复方氯化钠。GLP-1缓释珠直径600μm,内含3000个整合了GLP-1基因的人骨髓间充质干细胞,外被致密的藻酸盐外膜,以确保GLP-1产物可顺利释放而不引起免疫排斥。玻璃体内注射均在右眼视神经夹伤后立即进行。视神经夹伤后第23天用3％荧光金从双侧上丘做逆行标记,第28天取双眼球标本做视网膜铺片并在荧光显微镜下拍摄照片,采用人工双盲法进行视网膜神经节细胞计数。主要指标视网膜神经节细胞密度以及视网膜神经节细胞存活率。结果视网膜神经节细胞密度实验组与对照组分别为（2113±474）／mm2和（1734±424）／mm2,两组之间的差异有统计学意义（t=2．111,P=-0．046）。视网膜神经节细胞存活率实验组与对照组分别为（74±18）％和（57±16）％,两组之间的差异有统计学意义（t=-2．451,P=-0．022）。结论GLP-1缓释珠玻璃体内植入后对视神经夹伤大鼠视网膜神经节细胞具有保护作用,可以提高视网膜神经节细胞存活率。     

Neuroprotective effects of BDNF and GDNF in intravitreally transplanted mesenchymal stem cells after optic nerve crush in mice

AIM: To assess the neuro-protective effect of bone marrow mesenchymal stem cells (BMSCs) on retinal ganglion cells (RGCs) following optic nerve crush in mice. METHODS: C56BL/6J mice were treated with intravitreal injection of PBS, BMSCs, BDNF-interference BMSCs (BIM), and GDNF-interference BMSCs (GIM) following optic nerve crush, respectively. The number of surviving RGCs was determined by whole-mount retinas and frozen sections, while certain mRNA or protein was detected by q-PCR or ELISA, respectively. RESULTS: The density (cell number/mm2) of RGCs was 410.77±56.70 in the retina 21d after optic nerve crush without any treatment, compared to 1351.39±195.97 in the normal control (P<0.05). RGCs in BMSCs treated eyes was 625.07±89.64/mm2, significantly higher than that of no or PBS treatment (P<0.05). While RGCs was even less in the retina with intravitreal injection of BIM (354.07+39.77) and GIM (326.67+33.37) than that without treatment (P<0.05). BMSCs injection improved the internal BDNF expression in retinas. CONCLUSION: Optic nerve crush caused rust loss of RGCs and intravitreally transplanted BMSCs at some extent protected RGCs from death. The effect of BMSCs and level of BDNF in retinas are both related to BDNF and GDNF expression in BMSCs.     

Neuroprotective effect of sulfhydryl reduction in a rat optic nerve crush model

PURPOSE: The signaling of retinal ganglion cell (RGC) death after axotomy is partly dependent on the generation of reactive oxygen species. Shifting the RGC redox state toward reduction is protective in a dissociated mixed retinal culture model of axotomy. The hypothesis for the current study was that tris(2-carboxyethyl)phosphine (TCEP), a sulfhydryl reductant, would protect RGCs in a rat optic nerve crush model of axotomy. METHODS: RGCs of postnatal day 4 to 5 Long-Evans rats were retrogradely labeled with the fluorescent tracer DiI. At approximately 8 weeks of age, the left optic nerve of each rat was crushed with forceps and, immediately after, 4 muL of TCEP (or vehicle alone) was injected into the vitreous at the pars plana to a final concentration of 6 or 60 microM. The right eye served as the control. Eight or 14 days after the crush, the animals were killed, retinal wholemounts prepared, and DiI-labeled RGCs counted. Bandeiraea simplicifolia lectin (BSL-1) was used to identify microglia. RESULTS: The mean number of surviving RGCs at 8 days in eyes treated with 60 microM TCEP was significantly greater than in the vehicle group (1250 +/- 156 vs. 669 +/- 109 cells/mm(2); P = 0.0082). Similar results were recorded at 14 days. Labeling was not a result of microglia phagocytosing dying RGCs. No toxic effect on RGC survival was observed with TCEP injection alone. CONCLUSIONS: The sulfhydryl-reducing agent TCEP is neuroprotective of RGCs in an optic nerve crush model. Sulfhydryl oxidative modification may be a final common pathway for the signaling of RGC death by reactive oxygen species after axotomy.