PEDF对大鼠视神经急性损伤后神经节细胞的保护作用

目的:观察色素上皮衍生因子(pigment epithelium derived factor,PEDF)对大鼠视神经急性损伤后视网膜神经节细胞(retinal ganglion cells,RGCs)的保护作用.方法:选取健康雌性SD大鼠60只随机分为:空白组、模型组和实验组,每组各20只.采用视神经夹伤方法,建立大鼠视神经急性损伤模型.模型组制作视神经损伤模型成功后即刻向玻璃体腔注射平衡盐溶液5μL,之后的1、2wk分别向玻璃体腔注射平衡盐溶液5μL;而实验组在视神经损伤模型制作成功后即刻向玻璃体腔注射PEDF 5μL,同样在1、2wk时分别向玻璃体腔注射PEDF 5μL.通过HE 染色,光镜下观察视网膜形态学变化并且对视网膜神经节细胞进行计数.通过免疫组织化学半定量的方法对Bcl-2和Bax的表达进行检测,观察PEDF对受损视神经的影响.结果:HE染色观察,实验组神经节细胞从细胞形态上要好于模型组,且RGCs数量较模型组多.实验组的Bcl-2和Bax的蛋白表达与空白组、模型组比较,差异有统计学意义(P<0.05),实验组较模型组Bcl-2蛋白表达增加,Bax蛋白表达下降.结论:PEDF可通过上调视网膜Bcl-2蛋白的表达、减弱Bax蛋白表达,以减弱或抑制视神经损伤后RGCs的细胞凋亡,减轻视神经损伤.     

香菇多糖对视神经损伤视网膜节细胞保护作用的实验研究

目的 评估香菇多糖(LNT)对视神经损伤后的保护作用.方法 成年纯种新西兰大耳白兔按视神经夹伤后存活时间不同(1,3,7,14 d)随机分为4组,每只兔右眼为治疗眼(实验组),于伤后玻璃体腔内注射LNT;左眼为对照眼(对照组),伤后玻璃体腔内注射生理盐水.观察LNT实验组与对照组视网膜形态学改变,用TUNEL染色法对视网膜神经节细胞(RGC)做凋亡细胞的定位和计数,评估香菇多糖对视网膜神经节细胞的保护作用.结果 正常组视网膜内界膜平滑完整,三层细胞分界清楚,节细胞呈单层排列,内、外丛状层厚度、染色均匀.对照组损伤后视网膜厚度较正常组变薄,细胞排列疏松紊乱,节细胞数目减少,以伤后7 d最为严重.各时间点实验组与对照绀比较节细胞存活数增加,网膜厚度大于对照组,且细胞排列相对整齐.结论 兔视神经损伤后玻璃体腔内注射LNT能有效保护视网膜神经节细胞.     

蛇毒神经生长因子对大鼠视神经夹伤保护的电镜观察

目的研究蛇毒神经生长因子在视神经损伤后对视网膜神经节细胞的保护作用。方法将Wistar大鼠40只随机分为实验对照组和实验治疗组。制作实验性视神经夹伤模型,用头部宽1mm的微型血管夹夹伤大鼠右眼视神经后,实验治疗组向伤眼玻璃体腔内注入蛇毒神经生长因子100BU(0.025mL)。实验对照组向伤眼玻璃体腔内注入0.025mL平衡盐液。于损伤后第3d、7d、14d、30d、60d取材,用透射电镜观察不同时间段各组视网膜形态学变化。结果电镜下大鼠视网膜改变:实验治疗组和对照组电镜下均可见坏死和凋亡。伤后14d,实验治疗组视网膜微管数目比实验对照组较多,排列比较整齐。结论在视神经损伤早期,蛇毒神经生长因子能减轻视神经夹伤后微管的损坏,提高视网膜神经节细胞的存活数量,对视网膜神经节细胞有明显的保护作用。     

丙戊酸钠对大鼠视神经损伤后视网膜生长相关蛋白-43表达的影响

目的 研究丙戊酸钠对大鼠视神经损伤后视网膜生长相关蛋白-43（GAP-43）表达的影响,探讨丙戊酸钠在视神经损伤后的作用及其机制.方法 健康雄性SD大鼠60只（72只眼）,随机分3组：正常组（不做任何处理）12只（24只眼）、对照组（等量生理盐水腹腔注射）和治疗组（丙戊酸钠300 mg/kg腹腔注射）,每组24只大鼠（24只眼）.建立大鼠视神经不完全损伤模型,分别于损伤后3d、7d、14 d、21 d处死,光镜下观察视网膜神经节细胞的病理形态学变化,计算机图像分析技术和免疫组织化学技术半定量检测视网膜组织GAP-43的平均光密度值.结果 视神经损伤后对照组和治疗组视网膜神经节细胞数目均呈下降趋势.与对照组比较,治疗组视网膜神经节细胞空泡化程度轻,各层胞核排列相对密集整齐.治疗组GAP-43免疫组化染色的平均光密度值及阳性细胞计数均高于对照组.结论 由丙戊酸钠对视神经损伤后GAP-43表达的增强,可以推断丙戊酸钠对视神经损伤具有保护作用.     

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。      

Neuregulin-1对大鼠急性视神经损伤的保护作用研究

目的 拟建立大鼠急性视神经钳夹损伤模型,在大鼠视神经损伤后将不同的剂量的neuregulin-1(NRG-1)注入玻璃体腔内,研究NRG-1是否对视神经急性损伤有保护和修复作用,并以此推测视神经急性损伤的可能机制.方法 2月龄SD雄性大鼠100只.随机分为NRG-1治疗组、生理盐水对照组、阴性对照组;然后于1、2、7、14、28d各组行FVEP检查及眼底照相定性观察视神经受损及修复情况并分别处死部分动物,用组织病理检查、TUNEL原位凋亡检测等技术来观察和评价视网膜神经节细胞的数目及进行各组间视网膜神经节细胞凋亡数目的 比较.结果 从眼底照相、FVEP、HE染色、TUNEL原位凋亡检测等方面进行评估.结论 NRG-1能有效降低视网膜组织细胞的凋亡数目,并且其保护作用的效果可能与剂量有关.这些结果说明:大鼠急性视神经损伤后,给予NRG-1能降低视网膜神经节细胞的凋亡,说明NRG-1对于急性视神经损伤具有修复和保护作用.视神经损伤后,尽量保存视网膜神经节细胞免于凋亡是改善视神经损伤预后的关键.我们的研究结果提示:尽早使用外源性NRG-1等神经保护剂,保护RGCs等神经元,对于损伤后神经再生、进而神经功能的恢复可能有积极作用.     

丙戊酸钠在大鼠视神经损伤再生中的作用研究

目的 探讨丙戊酸钠在视神经损伤再生中的作用.方法 清洁级健康雄性SD大鼠60只,随机分3组：正常组12只（24只眼）、生理盐水对照组（对照组）和丙戊酸钠治疗组（治疗组）每组24只（24只眼）.正常组不做任何处理,两实验组均采用视神经钳夹法建立右眼视神经损伤模型,治疗组给予丙戊酸钠300 mg/kg腹腔注射,对照组给予等量生理盐水腹腔注射.分别于损伤后3d、7d、14 d、21 d取材,制备视网膜切片,光镜下观察视网膜神经节细胞（RGC）的病理形态学变化,以免疫组织化学技术观察脑源性神经营养因子（BDNF）的表达情况,计算机图像分析技术半定量检测视网膜组织BDNF的平均光密度值（AOD）.结果 与对照组比较,治疗组经丙戊酸钠注射后,视网膜神经节细胞水肿及空泡化程度轻,各层胞核排列相对密集整齐.相同时间点治疗组BDNF免疫组化染色的AOD值及阳性细胞计数均强于对照组和正常组.结论 丙戊酸钠可以促进视神经损伤后BDNF表达的上调,减少RGC的损伤,对视神经损伤具有保护作用.     

腺病毒载体介导的色素上皮衍生因子对大鼠视网膜缺血再灌注损伤的保护作用

目的:观察重组腺病毒介导的色素上皮衍生因子(Ad-PEDF)对大鼠视网膜缺血再灌注损伤的保护作用及机制。方法:选用健康大鼠96只,随机分为正常组、缺血再灌注组、缺血再灌注+Ad-CMV组,缺血再灌注+Ad-PEDF组,以前房加压的方法制备大鼠视网膜缺血再灌注模型,缺血再灌注+Ad-CMV组,缺血再灌注+Ad-PEDF组分别玻璃体腔注射Ad-CMV或Ad-PEDF1μL(滴度3.8×109/PFU),每组按照时间点12,24,72,168h,为4亚组,光学显微镜观察视网膜组织切片情况,并测量视网膜内层厚度及神经节细胞层神经节细胞数量。以TUNEL方法观察大鼠视网膜神经节细胞凋亡情况。结果:Ad-PEDF组视网膜内层厚度均超过缺血组及缺血+Ad-CMV组,Ad-PEDF组神经节细胞数目多于缺血组及Ad-CMV组,Ad-PEDF组视网膜神经节细胞凋亡细胞少于缺血组及Ad-CMV组,凋亡程度减轻,上述差异均具有显著性(P<0.05)。结论:腺病毒介导的色素上皮衍生因子玻璃体腔注射能够恢复大鼠视网膜缺血再灌注损伤所致的视网膜内层厚度降低,神经节细胞密度减少,具有保护作用。     

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.     

色素上皮源性因子对缺血-再灌注视网膜神经节细胞的保护作用

目的:研究色素上皮源性因子(pigment epithelium derived factor,PEDF)对高眼压诱导的大鼠视网膜缺血-再灌注后视网膜神经节细胞的保护作用.方法:经眼角膜进行前房平衡盐水(BSS)灌注,维持眼内压110 mmHg,以阻止视网膜正常血液灌注.60 min后取出灌注针头,恢复视网膜正常血流,从而建立大鼠视网膜缺血-再灌注模型.实验分为正常非缺血组和视网膜缺血-再灌注组,后者又分为生理盐水注射对照组和PEDF注射实验组,再灌注模型建立后立即向实验组大鼠玻璃体腔内注射0.2 g/L PEDF 2 μL.实验对照组用同样方法注射等量生理盐水.分别于注射后2 d和7 d进行眼球摘除,对视网膜进行光学显微镜形态学观察和Fas原位杂交免疫学分析,探讨PEDF对缺血-再灌注视网膜神经节细胞的保护作用.结果:缺血-再灌注2 d时生理盐水注射组和PEDF注射组视网膜神经节细胞明显少于正常对照组(P＜0.01)和(P＜0.05),PEDF注射组视网膜神经节细胞数较生理盐水注射组明显较多,相比有显著性差异(P＜0.05);视网膜神经节细胞计数再灌注7 d后结果与2 d时类似.再灌注2 d生理盐水注射组Fas阳性染色细胞比PEDF注射组明显较多(P＜0.05),生理盐水组比PEDF注射组阳性细胞百分率明显较高(P＜O.01);再灌注7 d时两组Fas阳性细胞计数无明显差异.结论:视网膜缺血-再灌注后即刻行玻璃体腔内PEDF注射可以改善视网膜神经节细胞的损伤并有一定保护作用.     

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.     

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.     

RGC death in mice after optic nerve crush injury: oxidative stress and neuroprotection

PURPOSE: To establish a method for morphometric analysis of retrogradely labeled retinal ganglion cells (RGCs) of the mouse retina, to be used for the study of molecular aspects of RGC survival and neuroprotection in this model; to evaluate the effect of overexpression of Cu-Zn-superoxide dismutase (CuZnSOD) on RGC survival after severe crush injury to the optic nerve, and to assess the effect of the alpha2-adrenoreceptor agonist brimonidine, recently shown to be neuroprotective, on RGC survival. METHODS: A severe crush injury was inflicted unilaterally in the orbital portion of the optic nerves of wild-type and transgenic (Tg-SOD) mice expressing three to four times more human CuZnSOD than the wild type. In each mouse all RGCs were labeled 72 hours before crush injury by stereotactic injection of the neurotracer dye FluoroGold (Fluorochrome, Denver, CO) into the superior colliculus. Survival of RGCs was then assessed morphometrically, with and without systemic injection of brimonidine. RESULTS: Two weeks after crush injury, the number of surviving RGCs was significantly lower in the Tg-SOD mice (596.6 +/- 71.9 cells/mm(2)) than in the wild-type control mice (863. 5 +/- 68 cells/mm(2)). There was no difference between the numbers of surviving RGCs in the uninjured retinas of the two strains (3708 +/- 231.3 cells/mm(2) and 3904 +/- 120 cells/mm(2), respectively). Systemic injections of brimonidine significantly reduced cell death in the Tg-SOD mice, but not in the wild type. CONCLUSIONS: Overexpression of CuZnSOD accelerates RGC death after optic nerve injury in mice. Activation of the alpha2-adrenoreceptor pathway by brimonidine enhances survival of RGCs in an in vivo transgenic model of excessive oxidative stress.     

Apoptotic retinal ganglion cell death in the DBA/2 mouse model of glaucoma

The DBA/2 mouse has been used as a model for spontaneous secondary glaucoma. We attempted to determine the in vivo time course and spatial distribution of retinal ganglion cells (RGCs) undergoing apoptotic death in DBA/2 mice. Female DBA/2 mice, 3, 9-10, 12, 15, and 18 months of age, received intravitreal injections of Annexin-V conjugated to AlexaFluor 1h prior to euthanasia. Retinas were fixed and flat-mounted. Annexin-V-positive RGCs in the hemiretina opposite the site of injection were counted, and their locations were recorded. Positive controls for detection of apoptotic RGCs by Annexin-V labeling included rats subjected to optic nerve ligation, and C57BL/6 mice subjected to either optic nerve ligation or intravitreal injection of NMDA. To verify that Annexin-V-labeled cells were RGCs, intravitreal Annexin-V injections were also performed on retinas pre-labeled retrogradely with FluoroGold or with DiI. Annexin-V-positive RGC locations were analyzed to determine possible clustering and areas of preferential loss. Annexin-V labeled apoptotic RGCs in eyes after optic nerve ligation, intravitreal NMDA injection, as well as in aged DBA/2 animals. In glaucomatous DBA/2 mice 95-100% of cells labeled with Annexin-V were also FluoroGold- and DiI-positive. This confirms that Annexin-V can be used to specifically detect apoptotic RGCs in rodent retinas. In DBA/2 mice, apoptotic RGC death is maximal from the 12th to the 15th month of age (ANOVA, p<0.001, Fisher's post hoc test) and occurs in clusters. These clusters are initially located in the midperipheral retina and progressively occur closer to the optic nerve head with increasing age. Retrograde axonal transport of FluoroGold in the glaucomatous mouse retina is functional until at least 2-3days prior to initiation of apoptotic RGC death.     

神经营养因子促进视神经夹伤后视网膜生长相关蛋白-43表达

目的：观察大鼠视神经夹伤后视网膜的神经生长相关蛋白－43（growth associated protein-43,GAP-43)的表达变化及胰状神经营养因子（ciliary neurotrophic factor CNTF)和腺病毒介导脑源性神经营养因子（adenovirally delivered brain-derived neurotrophic factor,Ad-BDNF)对视神经夹伤的保护作用。方法：在眼球后2mm处作视神经夹伤，制作SD大鼠视神经夹伤模型，通过巩膜进行玻璃体微量注射神经营养因子（neurotraphic factors,NFs)，应用免疫印迹法观察视网膜的GAP－43表达量的变化。结果：正常SD大鼠视网膜上GAP－43呈现低表达，分子量约为46．7ku；玻璃体注射CNTF，大鼠视神经夹伤后2周，GAP－43的表达增强（P＜0．05），玻璃体注射Ad-BDNF，在视神经夹伤后4周内GAP－43的表达增强（P＜0．05），但这种作用以视神经损伤后1周时最为明显。结论：玻璃体注射NFs能够在一定时间范围内促进神经夹伤的SD大鼠视网膜上GAP－43表达，其中Ad-BDNF的促进作用能够维持相对较长的时间。     

大鼠视神经夹伤模型中莫尼定的视网膜节细胞保护作用

目的 :研究莫尼定对大鼠视神经夹伤模型视网膜神经节细胞的保护作用。方法 :实验用SD大鼠 2 0只随机分为用药组 8只和对照组 12只。所有大鼠右眼用 40 g微型视神经夹紧贴球后夹持视神经 60秒 ,左眼未做夹持。用药组于夹伤前1小时及夹伤后每日腹腔注射莫尼定 1mg/kg ,阴性对照组于夹伤前 1小时及夹伤后每日腹腔注射生理盐水 5ml/kg ,实验观察2 8天。实验结束前 4天双上丘注射 3 %荧光金逆行标记视网膜神经节细胞。做视网膜铺片 ,距离视乳头中心上下左右各2mm拍摄照片 ,使用CPAS图像分析软件做节细胞定量分析 ,节细胞存活率 =右眼节细胞密度 /左眼节细胞密度× 10 0。结果 :用药组、对照组节细胞存活率分别为 61 0 1%和 53 48% ,两者之间存在显著性差异 (P =0 .0 3 5)。结论 :在大鼠视神经夹伤模型中 ,莫尼定具有明显的视网膜节细胞保护作用     

Experimental induction of retinal ganglion cell death in adult mice

PURPOSE: Retinal ganglion cells die by apoptosis during development and after trauma such as axonal damage and exposure to excitotoxins. Apoptosis is associated with changes in the expression of genes that regulate this process. The genes that regulate apoptosis in retinal ganglion cells have not been characterized primarily because previous studies have been limited to animal models in which gene function is not easily manipulated. To overcome this limitation, the rate and mechanism of retinal ganglion cell death in mice was characterized using optic nerve crush and intravitreal injections of the glutamate analog N-methyl-D-aspartate (NMDA). METHODS: To expose retinal ganglion cells (RGCs) to excitotoxins, adult CB6F1 mice were injected intravitreally in one eye with NMDA. In an alternative protocol to physically damage the axons in the optic nerve, the nerve was crushed using self-closing fine forceps. Each animal had one or the other procedure carried out on one eye. Loss of RGCs was monitored as a percentage of cells lost relative to the fellow untreated eye. Thy1 expression was examined using in situ hybridization. DNA fragmentation in dying cells was monitored using terminal transferase-dUTP nick-end labeling (TUNEL). RESULTS: RGCs comprise 67.5% +/- 6.5% (mean +/- SD) of cells in the ganglion cell layer (GCL) of control mice based on nuclear morphology and the presence of mRNA for the ganglion cell marker Thy1. One week after optic nerve crush, these cells started to die, progressing to a maximum loss of 57.8% +/- 8.1% of the cells in the GCL by 3 weeks. Cell loss after NMDA injection was dose dependent, with injections of 10 nanomoles having virtually no effect to a maximum loss of 72.5% +/- 12.1% of the cells in the GCL within 6 days after injection of 160 nanomoles NMDA. Cell death exhibited features of apoptosis after both optic nerve crush and NMDA injection, including the formation of pyknotic nuclei and TUNEL staining. CONCLUSIONS: Quantitative RGC death can be induced in mice using two distinct signaling pathways, making it possible to test the roles of genes in this process using transgenic animals.     

银杏叶提取物对视网膜神经节细胞保护作用的实验研究

目的探讨银杏叶提取物(EGb761)对大鼠视神经夹伤模型视网膜神经节细胞(RGC)的保护作用。设计实验研究。研究对象SPF级SD大鼠83只。方法右眼行视神经夹伤,于球后2mm处用40克压力微型视神经夹夹持视神经60秒,左眼作为正常对照。夹伤后2小时及此后每日一次灌胃给药,各组分别给予生理盐水5ml/kg(n=18)、1%灯盏细辛5ml/kg(n=16)、0.25% EGb761 5ml/kg(n=15)、1% EGb761 5ml/kg(n=18)和4% EGb761 5ml/kg(n=16)。视神经夹伤后第23天用荧光金作上丘逆行标记,第28天取眼球标本做视网膜铺片并拍摄照片,计数RGC并计算RGC的存活率。主要指标RGC存活率。结果生理盐水组、灯盏细辛组、0.25% EGb761组、1% EGb761组和4% EGb761组RGC存活率分别为60.59%、72.21%、69.10%、71.60%和74.20%。各剂量EGb761组与生理盐水组之间均有显著性差异(F=11.33,P<0.01),灯盏细辛组与生理盐水组之间也有显著性差异(P<0.01)。不同浓度EGb761各组之间无显著性差异(F=2.25,P>0.05),灯盏细辛组与不同浓度EGb761各组之间均无显著性差异(F=1.16.P>0.05)。结论EGb761能有效保护大鼠视神经夹伤模型的RGC。(眼科,2007,16:418-421)     

大鼠视神经损伤视网膜病理改变的实验研究

目的研究现神经损伤早期视网膜的病理改变。方法采用大鼠球后视神经横断伤和钳夹伤模型,观察视网膜组织学及超微结构的改变。结果1）光镜：早期表现为神经纤维层血管扩张,损伤后7、14天可见散在的核染色质边聚。空化的节细胞。2）电镜：损伤后1天节细胞出现胞浆成分疏松,内质网扩张等变性样改变,横断伤3天及钳夹伤7天可见节细胞坏死,部分节细胞凋亡。结论视神经损伤导致节细胞出现迟发性死亡,提示早期治疗具有重要意义。