Diosmin protects rat retina from ischemia/reperfusion injury

Abstract Objective: Diosmin, a natural flavone glycoside, possesses antioxidant activity and has been used to alleviate ischemia/reperfusion (I/R) injury. The aim of this study was to clarify whether the administration of diosmin has a protective effect against I/R injury induced using the high intraocular pressure (IOP) model in rat retina, and to determine the possible antioxidant mechanisms involved. Methods: Retinal I/R injury was induced in the rats by elevating the IOP to 110?mmHg for 60?min. Diosmin (100?mg/kg) or vehicle solution was administered intragastrically 30?min before the onset of ischemia and then daily after I/R injury until the animals were sacrificed. The levels of malondialdehyde (MDA) and the activities of total-superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the retinal tissues were determined 24?h after I/R injury. At 7 days post-I/R injury, electroretinograms (ERGs) were recorded, and the density of surviving retinal ganglion cells (RGCs) was estimated by counting retrograde tracer-labeled cells in whole-mounted retinas. Retinal histological changes were also examined and quantified using light microscopy. Results: Diosmin significantly decreased the MDA levels and increased the activities of T-SOD, GSH-Px, and CAT in the retina of rats compared with the ischemia group (P<0.05), and suppressed the I/R-induced reduction in the a- and b-wave amplitudes of the ERG (P<0.05). The thickness of the entire retina, inner nuclear layer, inner plexiform layer, and outer retinal layer and the number of cells in the ganglion cell layer were significantly less after I/R injury (P<0.05), and diosmin remarkably ameliorated these changes on retinal morphology. Diosmin also attenuated the I/R-induced loss of RGCs of the rat retina (P<0.05). Conclusion: Diosmin protected the retina from I/R injury, possibly via a mechanism involving the regulation of oxidative parameters.     

Role of extracellular signal-regulated kinase in glutamate-stimulated apoptosis of rat retinal ganglion cells

PURPOSE: To investigate the involvement of the extracellular signal-regulated kinase (ERK) signaling pathway after intravitrevous injection of glutamate in rat retina. METHODS: Three groups of five Sprague-Dawley rats each were studied. Group I was a normal control group, intravitreal saline injections. In Group II, one eye received an intravitreal glutamate injection (375 nmol, dissolved in saline) while the contralateral eye served as control. In Group III, intravitreal PD98059 (100 micro mol, an inhibitor of ERK) injections were administered 1 hr before glutamate injections. Seven days after injections, phosphorylated (activated) ERK in retina was localized by immunohistochemistry and fluorescent double labeling of retinal cryosections. Specific ERK blockade was documented to assess the functional significance of activated ERK. TUNEL staining was performed to assess apoptotic cell death. RESULTS: Expression of phosphorylated ERK in rat retina was observed in the inner nuclear layer, the outer nuclear layer, and the nerve fiber layer after 3 days intravitreous injection of glutamate, increasing significantly after 7 days. Double immunofluorescence labling demonstrated that the increased retinal immunostaining for phospho-ERK was predominantly localized to the retinal Müller cells after 7 days intravitreous injection of glutamate. Moreover, blocking activation of ERK significantly improved the number of TUNEL-positive cells in the eyes receiving intravitreal PD98059 injections compared with the eyes receiving glutamate injections. CONCLUSIONS: The ERK pathway is involved in signal transduction in the retina after excessive stimulation by glutamate, which may contribute to the antiapoptotic role in retinal ganglion cell death induced by glutamate.     

Interleukin-6 in retinal ischemia reperfusion injury in rats

PURPOSE: To study the role of interleukin (IL)-6 after retinal ischemia-reperfusion (I/R) injury in rats. METHODS: Intraocular pressure of adult male Lewis albino rats was raised to create retinal ischemia for 1 hour. Retinal reperfusion was reestablished, and the animals were killed at various time points after the injury. Their eyes were enucleated and processed for immunohistochemistry to detect IL-6 and ED-1 (a marker of microglial/phagocytic cells), enzyme-linked immunosorbent assay (ELISA) of IL-6 protein, and semiquantitative real-time RT-PCR for IL-6 mRNA. The neuroprotective effect of IL-6 was evaluated by giving intravitreal injections of 150 or 300 ng rat recombinant IL-6 to eyes immediately after I/R injury and counting cresyl violet-stained retinal ganglion cell layer cells (RGCLCs) and fluorochrome-labeled retinal ganglion cells (RGCs) on flat preparations of retinas at 7 days. RESULTS: IL-6-positive cells appeared after I/R injury in the inner plexiform layer (IPL) and the inner nuclear layer (INL). Their numbers were significantly higher 18 hours after the injury, and most of these cells were also ED-1 positive. ELISA showed noticeable increases in endogenous retinal IL-6 protein levels 8 hours after I/R injury. Semiquantitative real-time RT-PCR showed significant increases in endogenous retinal IL-6 mRNA levels between 2 and 18 hours. Exogenously added IL-6 prevented between 50% and 70% of RGC loss after I/R injury. CONCLUSIONS: IL-6 is upregulated after retinal I/R injury, and its expression by microglia/phagocytic cells may protect RGC layer neurons from I/R injury. Exogenously added IL-6 protects the inner retina after I/R injury.     

地塞米松对玻璃体积血兔视网膜病理变化的影响

目的:观察地塞米松(dexamethasone,Dxm)对兔玻璃体积血后视网膜病理变化的影响。方法:白兔24只,随机分为实验对照组(A),积血组(B)和Dxm干预组(C),每组8只。A组玻璃体内注入生理盐水0.2mL,B组、C组玻璃体内注入自体血0.2mL;注入后1,24,48h,A和B组给予生理盐水3mL/kg,C组给予Dxm3mg/kg。分别于造模后3,7,14,21d随机处死每组中的2兔4眼观察视网膜病理变化。结果:A组所有时间点,B组3,7d,C组3,7,14d视网膜形态正常。B组14d神经节细胞、内丛状层水样变性;21d视网膜内界膜不完整,内、外核层细胞和光感受器内、外节水样变性。C组21d神经节细胞染色变淡,内丛状层、内核层水样变性。结论:玻璃体积血可引起视网膜细胞水样变性,Dxm可缓解玻璃体积血后视网膜水样变性。     

Morphometric analysis of the macula in eyes with geographic atrophy due to age-related macular degeneration

PURPOSE: To evaluate the extent of neural cell death in eyes with geographic atrophy (GA). METHODS: Ten eyes with GA and five age-matched control eyes were selected for morphometric analysis. The nuclei of the ganglion cell, inner nuclear, and outer nuclear layers were counted in contiguous 100-microm segments from 1,500 microm nasal to 1,500 microm temporal to the fovea. RESULTS: The outer nuclear layer was most severely attenuated in eyes with GA, demonstrating a 76.9% reduction relative to control eyes (P < 0.0001). A significant loss of ganglion cells (by 30.7%) was also observed (P = 0.0008). There was no significant difference in the inner nuclear layer cells (P = 0.30). Among the GA eyes, the nuclei in all three layers were significantly reduced in segments in which the retinal pigment epithelium was completely absent (P 相似文献   

Morphometric analysis of the macula in eyes with disciform age-related macular degeneration

PURPOSE: To evaluate the extent of neural cell death in eyes with disciform age-related macular degeneration. METHODS: Six eyes with disciform degeneration at various stages and five age-matched control eyes were selected for morphometric analysis using digitized light microscopic images. Disciform scars were classified as subneurosensory retinal, subretinal pigment epithelial, or combined lesions. The nuclei of the ganglion cell, inner nuclear, and outer nuclear layers were counted in contiguous 100 microm segments spanning a distance from 1,500 microm nasal to 1,500 microm temporal to the fovea. RESULTS: The outer nuclear layer was most severely attenuated in eyes with disciform scars, demonstrating a 69.4% reduction in cell number relative to control eyes. A loss in retinal ganglion cells (by 7.3%) and an increase in inner nuclear layer cells (by 10%) were observed, but these changes were not significant. Photoreceptor loss was most pronounced when the disciform scar was not covered by the retinal pigment epithelium. CONCLUSION: The nuclei of the outer nuclear layer are significantly attenuated in eyes with disciform age-related macular degeneration, while the ganglion cell and inner nuclear layers are relatively preserved. These findings suggest that replacement of outer nuclear function, by either retinal transplantation or implantation of the intraocular retinal prosthesis, might be a feasible therapeutic option for patients with this condition.     

感觉神经对应激反应诱发的视网膜细胞凋亡的影响

目的 应用实验大鼠模型,观察感觉神经在应激反应诱发视网膜损伤中的作用.方法 采用结扎冠状动脉左前降支的方法制备急性心肌缺血模型;应用辣椒素去乳鼠感觉神经的方法制备去感觉神经大鼠模型.雄性SD大鼠24只(48眼),随机分为两组(每组12只24眼):结扎冠状动脉(CAO)3h和6h组.辣椒素去神经结扎冠状动脉(D-CAO)3h和6h组.采用TUNEL染色技术和caspase-3活性测定观察各组大鼠视网膜细胞凋亡情况.结果 CAO组与D-CAO组比较,TUNEL染色D-CAO各时点组视网膜细胞凋亡水平较CAO相应时点组显著升高(P＜0.001);凋亡主要集中于视网膜神经节细胞层、内核层、外核层及色素上皮层.D-CAO6小时组的总凋亡率明显高于D-CAO3小时组.Caspase-3活性测定D-CAO各时点组较CAO相应时点组活性明显升高(P＜0.01).结论 结扎冠状动脉后,辣椒素去神经大鼠视网膜细胞凋亡水平较未去神经大鼠视网膜细胞凋亡水平明显升高.提示:感觉神经参与了急性心肌缺血伤害性刺激的感受及信息传递和调制,抑制伤害性刺激诱发的神经源性机制的激活及传导过程,感觉神经可能对急性应激反应引发的视网膜组织损伤具有保护作用.     

Neuroprotective effect of small interfering RNA targeted to caspase-3 on rat retinal ganglion cell loss induced by ischemia and reperfusion injury

Purpose: To investigate neuroprotective effects of siRNA targeted to caspase-3 against ischemia and reperfusion (I/R) injury in rat eyes. Methods: Retinal ischemia was induced in Wistar rats by increasing the intraocular pressure (IOP) to 110 mmHg for 120 min. To examine the effect of siRNA on rat caspase-3, siRNA was injected into the vitreous cavity 24 h prior to induction of retinal ischemia. Eyes were removed at 2, 7 or 14 days later, and then analyzed for the number of retinal ganglion cells (RGCs), the retinal thickness and the amount of apoptosis of the retinal neural cells (as demonstrated by the TUNEL assay). The amount of caspase-3 mRNA was analyzed by rt-PCR. Differences between groups were evaluated by an unpaired t test. Results: The numbers of RGCs in the saline and non-silencing siRNA controls were reduced significantly at 2 and 7 days after the I/R injury. RGCs were significantly retained in eyes pretreated with siRNA targeted to caspase-3 as compared to the control eyes at 2 days after the I/R injury. Inner retinal thickness in the control eyes was significantly thinner as compared to the treated eyes at 2 and 7 days after the I/R injury. After siRNA treatment, the amount of caspase-3 mRNA was significantly lower when compared to the saline control group. Conclusions: The injection of siRNA targeted to caspase-3 into the vitreous cavity of rat eyes may block caspase-3, and may thus be able to prevent retinal cell death associated with ischemic injury. As inhibition of the apoptosis pathway may provide a neuroprotective effect, examination of new strategies for treating these disorders needs to be undertaken.     

RCS大鼠视网膜内核层变性的超微结构研究

目的　证实RCS大鼠视网膜内核层存在神经原变性。方法　利用光学显微镜和透射电子显微镜观察出生后第 18、2 0、2 8、3 5、42、45、5 6、60、70和 10 0d的RCS大鼠视网膜和正常SD大鼠视网膜组织结构的变化。并用TUNEL方法证实视网膜神经细胞存在凋亡。结果　和正常SD大鼠视网膜比较 ,RCS大鼠 18～ 2 0d开始视网膜变性 ,光感受器细胞死亡 ,内核层细胞也有不同程度的变性。RCS大鼠在出生后 2 5d ,视网膜外核层细胞核TUNEL呈阳性 ,出生后 3 5～ 45d呈强阳性 ,视网膜内核层细胞核TUNEL标记呈阳性。结论　RCS大鼠视网膜内核层细胞存在神经原变性 ,视网膜内核层细胞死亡存在凋亡这一方式。跨神经原变性很可能是这些细胞变性的机制。RCS大鼠视网膜外核层细胞存在神经原变性 ,其死亡以凋亡为主     

Effects of nerve growth factor for retinal cell survival in experimental retinal detachment

PURPOSE: To investigate the neuron protective effect of recombined nerve growth factor (rNGF) on retinal cell damage induced by experimental retinal detachment. METHODS: Experimental retinal detachment models were created in Sprague-Dawley rats by subretinal injection of sodium hyaluronate. Intravitreal injection of rNGF (5 microg/eye) or phosphate-buffered saline (PBS) was separately applied every 4 days after retinal detachment. The rat eyes were then observed and sacrificed at various time points. Morphologic changes were observed by light microscopy, electron microscopy, and cell counts. Apoptosis of retinal cells was detected by TUNEL assay. RESULTS: After retinal detachment, most eyes from NGF-treated groups showed better organized structure of retinal cells than those from the PBS-treated control groups. Cell counts indicated that the nuclei numbers in the outer nuclear layer (ONL), inner nuclear layer (INL), and ganglion cell layer (GCL) of NGF-treated groups were significantly more than those from PBS-treated control group (p < 0.05) after retinal reattachment. TUNEL-positive cells were identified in ONL, INL, and GCL. They peaked at the fourth day after retinal detachment in both the NGF-treated groups and the control groups. But the cell counts of apoptosis revealed that the NGF-treated retina had less TUNEL-positive cells than the control groups (p < 0.05). CONCLUSIONS: The results showed that intravitreal injection of exogenous NGF can protect retinal cells from degeneration and apoptosis in experimental retinal detachment. It may exert its neuroprotection effect by preventing the apoptosis of retinal cells after retinal detachment.     

Retinal ischemia and reperfusion causes capillary degeneration: similarities to diabetes

PURPOSE: Retinal neurons and vasculature interact with each other under normal conditions, and occlusion of the retinal vasculature can result in damage to retinal neurons. Whether damage to the neural retina will damage the vasculature, however, is less clear. This study was conducted to explore the relationship between vascular and nonvascular cells of the retina. The response of the retinal vasculature to an injury (ischemia and reperfusion; I/R) that is known to cause neuronal degeneration was studied. METHODS: I/R injury to the retinas was induced in Lewis rats and C57BL/6J mice by elevating intraocular pressure (IOP), and reperfusion was established immediately afterward. Some rats were pretreated with aminoguanidine (AMG, 50 mg/Kg BW in drinking water) before the procedure. Poly(ADP-ribose) polymerase (PARP) activity and expression of inducible nitric oxide synthase (iNOS), and cycloxygenase-2 (COX-2) were measured by Western blot analysis, and levels of TNF-alpha and intercellular adhesion molecule (ICAM)-1 mRNA were measured by qPCR at 2 and 7 days after the procedure. Also at 2 and 7 days after the I/R injury, apoptosis of retinal neural cells (demonstrated by TUNEL assay), density of cells in the ganglion cell layer, and thickness of retinas were quantitated, and the number of TUNEL-positive capillary cells and degenerated capillaries were assessed. Retinal neurodegeneration and capillary degeneration were also examined in C57BL/6J mice 2, 5, 8, and 14 days after I/R injury. RESULTS: As expected, loss of cells in the retinal ganglion cell layer was apparent 2 days after I/R injury in the rat and mouse models. In contrast, the retinal vasculature had essentially no pathology at this time in either model. Surprisingly, the number of degenerated capillaries increased greatly by 7 to 8 days after the injury. Administration of aminoguanidine significantly inhibited the I/R-induced capillary degeneration as well as neurodegeneration in the rat model. Retinal I/R caused increased PARP activity (detected by poly(ADP-ribosy)lated proteins), as well as upregulation of iNOS, COX-2, TNF-alpha, and ICAM-1 levels in rats, consistent with an inflammatory process. CONCLUSIONS: Capillary degeneration is an unrecognized component of acutely elevated IOP and develops only after neurodegeneration is severe. Thus, this finding raises the possibility that damage to the neural retina contributes to capillary degeneration. Aminoguanidine, a nonspecific inhibitor of iNOS, inhibited I/R-induced degeneration of both neuronal and vascular cells of the retina. The model of retinal ischemia and reperfusion will be a useful tool for investigating the relationship between neuronal damage and vascular damage in glaucoma and other diseases such as diabetic retinopathy.     

Retardation of photoreceptor degeneration in the detached retina of rd1 mouse

PURPOSE: To study the neuroprotective effect of experimental retinal detachment (RD) on photoreceptor degeneration in rd1 mice. METHODS: RD was produced in the eyes of rd1 mice at postnatal day (P) 9. These eyes were collected and compared to controls without RD. The effects of RD on retinal degeneration were evaluated by histochemical staining of nuclei in the outer nuclear layer (ONL), rod and cone photoreceptors, and retinal vessels at P30 in retinal sections and flatmounts. Apoptotic photoreceptors were detected by TdT-mediated dUTP nick-end labeling (TUNEL) at P15. Mice with or without RD were also reared in darkness and evaluated immunohistochemically at P30. RESULTS: The numbers of rhodopsin-positive (rod), peanut agglutinin-positive (cone), and diamino-2-phenyl-indol-stained (rod-plus-cone) cells in the ONL were increased by 2.0-fold, 1.3-fold, and 1.2-fold, respectively, in the rd1 eyes with RD compared to those without RD at P30. In the detached retina, the cone photoreceptor inner/outer segment structures and the deep retinal vessels surrounding the inner nuclear layer and the ONL, but not the ganglion cell layer, were preserved. At P15, TUNEL-positive cell numbers in the ONL were significantly reduced in the eyes with RD. Light exposure had no effect on photoreceptor degeneration in the eyes with or without RD. CONCLUSIONS: RD mediates the preservation of cone and rod photoreceptors in the ONL and surrounding vascular structures by reducing the rate of apoptosis of photoreceptors in rd1 mice. Light deprivation does not appear to be one of the mechanisms of photoreceptor protection in the detached retinas in these mice.     

氩离子激光光凝前后糖尿病大鼠眼内组织中色素上皮衍生因子的表达

目的:观察氩离子激光视网膜光凝后糖尿病大鼠眼玻璃体及视网膜组织内色素上皮衍生因子(pigment epithelium-derived factor,PEDF)蛋白质表达的变化。方法:选用先天性糖尿病GK大鼠20只,对所有大鼠左眼施行氩离子激光视网膜光凝,右眼不进行光凝,作为自体对照。激光光凝后3d处死动物,取出眼球,WesternBlot和免疫组织化学染色检测玻璃体和视网膜组织中PEDF蛋白质表达的变化。结果:氩离子激光视网膜光凝后糖尿病大鼠玻璃体和视网膜中PEDF蛋白的表达均明显升高(P<0.01);且PEDF蛋白主要存在于RPE细胞层、光感受器细胞层、外核层和神经节细胞层,内核层表达的强度低于上述4层。结论:氩离子激光光凝可以上调糖尿病大鼠玻璃体和视网膜组织PEDF表达,抑制新生血管形成,达到治疗的目的。     

婴儿黄斑区视网膜发育变化的动态观察

目的 观察婴儿视网膜黄斑区形态及视网膜各层厚度变化。方法 随机选取新生儿重症监护病房中的婴儿58例86只眼纳入研究。根据不同矫正胎龄对婴儿进行分组。其中,矫正胎龄＜32周组10例14只眼;33～36周组26例39只眼;37～41周组12例18只眼;≥42周组10例15只眼。随机选择无器质性眼病的成人12名22只眼作为成人组。所有婴儿及成人均行便携式光相干断层扫描（OCT）检查。着重观察婴儿黄斑区形态。同时,测量婴儿及成人黄斑中心凹及距中心凹750、1500 μm处旁中心凹的神经上皮层、内层视网膜、外层视网膜、神经纤维层、节细胞层、内丛状层、内核层、外丛状层、外核层厚度。分析视网膜各层厚度与矫正胎龄的相关性。结果 婴儿早期的黄斑中心凹凹陷浅,随着矫正胎龄增长凹陷逐渐加深并接近成人形态。婴儿外层视网膜结构较内层完善,随着矫正胎龄的增长逐渐出现外界膜、光感受器内外节连接（IS/OS）、光感受器外节/视网膜色素上皮（OS/RPE）层。外界膜、IS/OS、OS/RPE层最早出现时间分别为矫正胎龄32+6、35、47+6周。RPE层、脉络膜血管层厚度均随矫正胎龄增长逐渐增厚。婴儿组、成人组之间距中心凹750 μm处内层视网膜、1500 μm处神经纤维层和中心凹及距中心凹750、1500 μm处节细胞层厚度比较,差异无统计学意义（P＞0.01)。其他视网膜各层厚度在婴儿组及成人组间,以及在不同矫正胎龄组组内间差异均有统计学意义（P＜0.01）。相关性分析发现,除节细胞层外,其他视网膜各层厚度均与矫正胎龄有相关性(P＜0.05)。结论 婴儿早期的黄斑中心凹凹陷浅,随着矫正胎龄增长凹陷逐渐加深并接近成人形态。婴儿早期黄斑区外层视网膜逐渐增厚,其中以内外核层增减变化最为明显。视网膜各层随着矫正胎龄增长逐渐增厚,但发育速度并不完全一致。     

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.     

Comparison of Each Retinal Layer Thicknesses between Eyes with Central Retinal Vein Occlusion and Normal Contralateral Eyes

PurposeTo evaluate the difference in each retinal layer thickness in central retinal vein occlusion (CRVO) with resolved macular edema after intravitreal antivascular endothelial growth factor injection and normal contralateral eyes..MethodsPatients with ischemic and nonischemic CRVO whose macular edema resolved after intravitreal antivascular endothelial growth factor injections and did not recur for at least 6 months, and a normal contralateral eye were enrolled. Each retinal layer thickness between CRVO and normal contralateral eyes was compared according to Early Treatment Diabetic Retinopathy Study subfields using spectral domain optical coherence tomography.ResultsThe thicknesses of outer nuclear layer, photoreceptor layer, and retinal pigment epithelium in central ring, ganglion cell layer, inner plexiform layer, outer nuclear layer, and photoreceptor layer in the inner ring, and ganglion cell layer in the outer ring of CRVO eyes were significantly thinner than those of normal contralateral eyes (all p < 0.05). Whereas, inner nuclear layer and outer plexiform layer thicknesses in central ring of CRVO eyes were 23.86 ± 8.8 and 25.76 ± 7.6 μm, respectively, which was significantly thicker than those of normal contralateral eyes (19.52 ± 7.7 and 22.76 ± 6.5 μm; p = 0.019 and p = 0.043, respectively). Additionally, the mean best-corrected visual acuity of CRVO eyes were significantly correlated with photoreceptor layer thickness in central ring (p = 0.005).ConclusionsIn CRVO eyes with resolved macular edema, the outer retinal layers were thinner as well as inner retinal layers, whereas inner plexiform layer and outer nuclear layer were thicker than normal fellow eyes. Additionally, photoreceptor layer thickness in foveal area had a significant impact on visual acuity in CRVO.     

大麻素受体在大鼠视网膜中的表达和分布

目的 研究大麻素CB1和CB2受体在幼年、成年和老龄大鼠视网膜组织的表达和分布.方法 研究采用免疫组织化学、Western印迹法和视网膜神经节细胞的上丘逆行追踪标记技术.结果 CB1和CB2受体在成年大鼠视网膜上均有较为丰富的表达,其中CB1受体的主要表达部位是外核层（ONL）、内核层（INL）和视神经节细胞层（GCL）,以及外网状层（OPL）和内网状层（IPL）;CB2的主要表达部位是GCL、INL、ONL的细胞膜和OPL,以及Müller胶质细胞的终足和突起上.免疫荧光双标结果显示,CB1和CB2受体在几乎所有的大鼠视网膜神经节细胞均有表达.CB1和CB2受体在幼年和老龄大鼠视网膜的表达分布与成年大鼠相似.结论 大麻素CB1和CB2受体在大鼠视网膜广泛分布和表达,从幼年到老龄,其表达和分布相似,提示在出生后早期这些受体的发育已经基本完成.大麻素受体系统在视网膜信息处理的调控和视网膜神经保护中可能发挥重要作用.     

Expression of thromboxane synthase and the thromboxane-prostanoid receptor in the mouse and rat retina

Experimental models of the diabetic retina have suggested a pathological role for thromboxane. To date however, little information is available as to the cellular locations of retinal thromboxane synthase (TxS), or its receptor, even in non-diabetic controls. In this study, C57BL/6 mice and Wistar rats were injected with streptozotocin to induce diabetes, or with buffer for non-diabetic controls. Four weeks following the injection, eyes were enucleated and labeled for TxS and the thromboxane-prostanoid (TP) receptor. Immunofluorescent intensity was quantified in the ganglion cell plus inner plexiform layers, inner nuclear layer, outer plexiform layer, outer nuclear layer, and photoreceptor inner segment. Even in control mice and rats, all layers of the retina showed immunoreactivity for TxS and the TP receptor: however, the pattern of expression demonstrated an inverse relationship, with the highest TxS staining in the inner retina, and the highest TP receptor staining in the outer retina (more specifically, in the photoreceptor inner segment). Four weeks of hyperglycemia did not increase the retinal levels of TxS or TP receptor; however, TP receptor intensities in the outer retina of diabetic rats were highly variable (mostly high but some low), with no values from the photoreceptor inner segment in the same range as obtained from controls.     

Retinal neuroprotection against ischemic injury mediated by intraocular gene transfer of pigment epithelium-derived factor

PURPOSE. To determine whether intraocular gene transfer of pigment epithelium-derived factor (PEDF) protects the retina from ischemia-reperfusion injury. METHODS. Four days before induction of pressure-induced ischemia, Lewis rats received intravitreous injection of 3 x 10(9) particles of an adenovirus vector expressing PEDF (AdPEDF.11) in one eye and 3 x 10(9) particles of an empty adenovirus vector (AdNull.11) in the contralateral eye. Seven days after reperfusion, eyes were enucleated and processed for morphometric analysis. Apoptotic cells stained by TdT-dUTP terminal nick-end labeling (TUNEL) in the retina were counted 12 hours after initiation of reperfusion. Retina levels of PEDF were measured by enzyme-linked immunosorbent assay. RESULTS. PEDF levels in retinal homogenates from eyes receiving AdPEDF.11 injection were well above the background levels in the untreated baseline and control eyes (P = 0.04). Retinal thickness was preserved in AdPEDF.11-treated eyes. Retinal cell density was significantly greater in the ganglion cell layer (GCL; P = 0.014), inner nuclear layer (INL; P = 0.008), and outer nuclear layer (ONL; P = 0.008) of AdPEDF.11-treated eyes compared with the corresponding layers in AdNull.11-treated eyes. AdNull.11-treated eyes also had significantly more TUNEL-positive cells in these layers than AdPEDF.11-treated eyes (P < 0.05). CONCLUSIONS. Adenoviral vector-mediated intraocular expression of PEDF significantly increases cell survival after ischemia-reperfusion injury of the retina. The protective effect may result from inhibition of ischemia-induced apoptosis. This study provides proof of concept for a gene transfer approach directed at interrupting programmed cell death induced by retinal ischemic insult.     

A microscopic study of herpes simplex virus retinopathy in mice

ICR white mice were inoculated with herpes simplex virus (HSV) type I in the anterior chamber of one eye. Animals were killed at intervals of 2, 4, 6, 8, and 10 days and both eyes were obtained for light and electron microscopic study of retinal changes. HSV retinopathy developed in 42 (91%) of 46 inoculated eyes. Fourteen (88%) of sixteen noninoculated eyes examined after the sixth postinoculation day developed HSV retinopathy. The earliest signs of retinopathy in the inoculated eye were peripheral retinal vasculitis and inflammatory cells throughout the nerve fiber layer on day 2. No virus was found in retinal tissue until day 4, at which time disruption of outer retinal layers (outer nuclear layer and layer of rods and cones) was observed in the peripheral retina. The earliest signs of retinopathy in the noninoculated eye were isolated foci of outer retinal disruption in the posterior retina on day 6. The inflammation accompanying early retinal changes of HSV retinopathy were more severe in the inoculated eye. Electron microscopy of both eyes revealed viral particles in the inner nuclear and ganglion cell layers at the time of outer retinal disruption, but viral particles were seen only rarely in the outer retinal layers at this stage. Early disruption of normal retinal architecture may be due to infection and destruction of Muller cells. The retinopathy progressed in both eyes to total destruction of the retina by day 10. Viral infection of the retinal pigment epithelium occurred, but viral particles were seen only rarely in the underlying choroid. This model may be useful for the study of HSV retinopathy in humans.