Heme oxygenase (HO)-1 and -2 isozymes are important markers for the oxidative stress. We localized HO-1 and HO-2 immunoreactivities and assessed the effect of aging on distribution of HO in the young and aged rat retina by immunohistochemical method. HO-1 and HO-2 showed partly different patterns of localization, indicating possibilities of different regulation of these two isozymes in the retina. HO-2 immunoreactivity was localized to some retinal neurons in ganglion cell layer and inner nuclear layer involving both of plexiform layers and pigment epithelium. The distribution of HO-2 positive cells did not show any difference between aged and young rat. In the case of HO-1, the immunoreactivity is found in retinal layers except outer nuclear layer and layer of rods and cones of young rat retina. The distribution of HO-1 immunoreactivity in old rat retina does not show remarkable difference compared with that in young rat retina, except in inner nuclear layer, outer plexiform layer and pigment epithelium. HO-1 positive components increased in inner nuclear layer, and decreased in outer plexiform layer and pigment epithelium with aging. This may suggest that the possibility of decrease in HO-1 mediated protective function against oxidative stress in outer retinal region of old rat. Another isozyme, HO-2, may not be influenced by normal aging process in rat retina. However, the localization of HO-1 and HO-2 in retina suggests that these two isozymes contribute to visual impairment in normal aging process.
Aging ; Animals ; Epithelium ; Ganglion Cysts ; Heme Oxygenase (Decyclizing)* ; Heme* ; Immunohistochemistry ; Isoenzymes* ; Oxidative Stress ; Photoreceptor Cells, Vertebrate ; Rats* ; Retina* ; Retinal Neurons ; Retinaldehyde ; Vision Disorders

In order to study the functional and structural alterations of the retina in SD rat model after methanol intoxication, 35 rats were divided randomly into five groups administrated with saline, 3-day high dose, 7-day high dose, 3-day low dose and 7-day low dose methanol separately. The retinal function of each group was assessed by flash electroretinogram (F-ERG) 3 and 7 days after methanol poisoning. The microstructure and ultrastructure of the retina were observed at the same time. The high-dose methanol intoxication induced irreversible retinal functional and structural damages 3 days after poisoning, which included prolonged latency and reduced amplitude of the Max-reaction of F-ERG. These injuries were aggravated 7 days after poisoning. Meanwhile, the latency and amplitude of the Cone-reaction of F-ERG were also affected 3 days after poisoning, but there were no further worsening tendency 7 days after poisoning. The retinal histological analysis showed cellular edema, heteromorphy and disarrangement, tissular loosen of the inner nuclear layer and photoreceptors layer. The mitochondrial damage began at the photoreceptors layer and developed further into the inner nuclear layer. The low-dose methanol intoxication only caused transient damage of the retina. Our results showed that the function and structure of the photoreceptor and inner nuclear layer were the primary target of methanol intoxication and that the rod cells were more sensitive to methanol intoxication than the cone cells. The mitochondrial damage developed from outer layer to inner layer of the retina.
Animals ; Edema/pathology* ; Electroretinography ; Forensic Medicine ; Male ; Methanol/poisoning* ; Mitochondria/pathology* ; Photoreceptor Cells/pathology* ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Retina/physiopathology* ; Retinal Cone Photoreceptor Cells/pathology* ; Retinal Diseases/pathology* ; Retinal Rod Photoreceptor Cells/pathology* ; Time Factors

The role of GABA or glycine as an inhibitory neurotransmitter is well established, and GABAergic or glycinergic neurons appear to play an important role in the mammalian retinas. It has been reported that certain amacrine, bipolar, displaced amacrine and ganglion cells are consistently labeled with anti-GABA or anti-glycine antisera in the mammalian retinae so far, and it has been suggested that colocalization of GABA and glycine within the retinal neurons could be common in the mammalian retina by recent immunecytochemical and electrophysiological studies. This study was conducted to localize GABAergic and glycinergic neurons and to define whether GABA and glycine are colocalized within same retinal neurons of the rat retina by immunocytochemical method using anti-GABA and anti-glycine antisera. The results were as follows : 1. GABAergic neurons of the rat retina were amacrine, interplexiform, bipolar, displaced amacrine and ganglion cells, and processes of GABAergic neurons formed dense networks with distinct two bands in the inner plexiform layer. 2. Glycinergic neurons were amacrine, bipolar, displaced amacrine and ganglion cells,and their processes were evenly distributed as dense networks through whole inner plexiform layer. 3. 28.5% of GABA immunoreactive amacrine cells and 9.8% of GABA immunoreactive bipolar cells located in the inner nuclear layer,and 11.9% of labeled neurons located in the ganglion cell layer showed glycine immunoreactivity in the rat retina. These results demonstrate that GABA and glycine, major inhibitory neurotransmitters, are colocalized within certain amacrine and displaced amacrine cells, and a few bipolar cells, and that neurons synthesizing and utilizing both GABA and glycine as their neurotransmitters may play an unique role in the visual processing in the rat retina.
Amacrine Cells ; Animals ; GABAergic Neurons ; gamma-Aminobutyric Acid* ; Ganglion Cysts ; Glycine* ; Immune Sera ; Neurons* ; Neurotransmitter Agents ; Rats* ; Retina* ; Retinal Neurons

OBJECTIVETo study the effect of Vaccinium uliginosum L., (VU) on the electroretinogram (ERG) and retinal pathological changes in rabbits after light-induced damage.

METHODSTwenty-eight Chinchilla rabbits were randomly divided into four groups: administration beforehand (A), administration after injury (B), light injury without administration (C), and blank (D) groups. After a 4-week administration of VU homogenate at 4.8 g/(kg·d) once a day in group A, ERG in groups A, B and C were recorded according to the standards set by the International Society for Clinical Electrophysiology of Vision (ISCEV). Except for group D, the groups were then exposed to strong light. Just after that, group A stopped receiving VU treatment and group B started to receive it. Then ERGs in all groups were recorded after 1 day, 1 week, and 2 weeks. Throughout the whole process groups which were not fed with VU were fed with normal saline. Finally, the tissues and structures of all the groups were observed and the thickness of the outer nuclear layers (ONL) was measured.

RESULTS(1) After 4-week feeding with VU, the latency time of ERG in group A became shorter than those in the other groups and the amplitude increased. After being exposed to strong light, the latency time lengthened and amplitude decreased in all the injury groups, but comparing at each time point, the measured values in group A were better than those in group C. With the accumulation of VU, the ERG in group B improved, and finally, all of the detected values became better than those in group C. (2) Retinae in group D were normal in histology and the layers were in order but those in group C became disarranged. The injuries in groups A and B were minor compared with those in group C. The thickness of the ONL in group C was significantly thinner than in the other groups (P=0.000), and that in groups A and B was thicker than that in group C, although thinner than in group D. That in group A was thicker than in group B.

CONCLUSIONSVU can relieve the injury to rabbit retinae exposed to normal day and night rhythm, alleviate the harm caused by light when used beforehand, and repair the light damage to the retina.

Animals ; Electroretinography ; Light ; Plant Extracts ; pharmacology ; Rabbits ; Retina ; drug effects ; pathology ; physiopathology ; radiation effects ; Retinal Cone Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Retinal Rod Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Time Factors ; Vaccinium ; chemistry

Retinal horizontal cell is second-order neuron that integrates the information from photoreceptors over large retinal areas, mediating the lateral spread of visual signals to distant retina. The Neurofilament proteins, considered as neuronal markers, have been imunolocalized to mammalian retinal horizontal cess. However, the immunolabeling of Neurofilament in human, has been focused on the studies of visual pathway and large ganglion cells The goal of this study is to see whether human retinal horizontal cells are indeed neuronal nature or glial nature by immunogold labeling for electron microscopy. The sections of 65 year-old human retina showed the expression of Neurofilament by horizontal cells, which confirms the evidence of human retinal horizontal cell as neuronal nature.
Aged ; Ganglion Cysts ; Humans* ; Microscopy, Electron ; Negotiating ; Neurofilament Proteins ; Neurons ; Retina ; Retinal Horizontal Cells* ; Retinaldehyde* ; Visual Pathways

Animals ; Embryo, Mammalian ; Humans ; Photoreceptor Cells, Vertebrate ; metabolism ; physiology ; Retinal Ganglion Cells ; metabolism ; physiology ; Retinal Pigments ; metabolism

Substance P (Sub P) being composed of 11 amino acids sequence is a kind of tachykinin family peptides. It has been known that this substance plays a role of neurotransmitter and/or neuromodulator and is a very potent vascular growth factor in the nervous system. This study has been investigated expression pattern of Sub P in the rat retina at normal and alteration of Sub P expression following diabetic injury using immunohistochemistry. Diabetic condition was induced by a single injection of streptozotocin in Sprague-Dawley rats aged 8 weeks. The animals showing high blood glucose levels (above 300 mg/dL) were cared for 1, 4, 8 and 12 weeks, respectively. The whole-mounted or sectional preparations of the retinas were used for Sub P immunohistochemistry. Sub P immunoreactivity has been localized in subsets of amacrine cells in the inner nuclear layer (INL) and displaced amacrine cells in the ganglion cell layer (GCL) in the normal retina. The dendrites from amacrine cells in the INL were ramified with strata 1 and 3, and those from displaced amacrine cells in the GCL with strata 5 of the inner plexiform layer. Sub P immunoreactive neurons in both the INL and the GCL were more densely populated in the superior half of the retina. During diabetes, the cell number of Sub P immunoreactive neurons was decreased to one third of the normal value at 4 weeks of diabetes and then slightly increased to half of the normal value at 12 weeks of diabetes. In addition, Sub P mRNA levels were reduced at 4 weeks but reincreased at 12 weeks. These results suggest that Sub P in the rat retina at normal state may function differentially in the superior or the inferior halves and Sub P synthetic pathway in the retinal neurons maybe irradiated in earlier stages of diabetic retinopathy.
Amacrine Cells ; Amino Acids ; Animals ; Blood Glucose ; Cell Count ; Dendrites ; Diabetic Retinopathy ; Ganglion Cysts ; Humans ; Immunohistochemistry ; Nervous System ; Neurons ; Neuropeptides ; Neurotransmitter Agents ; Peptides ; Rats* ; Rats, Sprague-Dawley ; Reference Values ; Retina* ; Retinal Neurons ; RNA, Messenger ; Streptozocin ; Substance P* ; Tachykinins

PURPOSE: This study investigated the expression of three isoforms of nitric oxide synthase (NOS): neuronal (nNOS), inducible (iNOS), and endothelial (eNOS) in an experimental rat model of chronic glaucoma. The aim was to research the role of nitric oxide (NO) as a neurotoxic molecule in connection with damage to and the degeneration of retinal ganglion cells in glaucoma. METHODS: Retinal tissues were obtained after inducing chronic elevation of intraocular pressure by cauterization of episcleral vessels. We then performed quantification and localization of NOS isoforms through western blot and immuno-fluorescence staining of the tissues. RESULTS: The expression of nNOS and iNOS increased significantly but that of eNOS did not. nNOS expressed in the amacrine and displaced amacrine cell of the normal retinal tissue, as well as in retinal ganglion cells in the experimental group. iNOS that expressed in the microglia of the normal retinal tissue was also expressed in the cell thought to be an astrocyte or Muller cell end-feet in the experimental group. Administration of L-NAME (NG-nitro-L-arginine-methyl-esther), a non-specific NOS inhibitor, tended to reduce retinal ganglion cell loss, but this result was without statistical significance. CONCLUSIONS: These results showed that the cytotoxicity of excessive NO took part in retinal ganglion cell loss in glaucoma, and the expression of nNOS in retinal ganglion cells suggests that it may play an important role in the selective death of the retinal ganglion cell.
Amacrine Cells ; Animals ; Astrocytes ; Blotting, Western ; Cautery ; Glaucoma* ; Intraocular Pressure ; Microglia ; Models, Animal* ; Neurons ; NG-Nitroarginine Methyl Ester ; Nitric Oxide Synthase* ; Nitric Oxide* ; Protein Isoforms ; Rats* ; Retinal Ganglion Cells ; Retinaldehyde

PURPOSE: To investigate which spectral domain optical coherence tomography (SD-OCT) findings predict visual outcome after anti-vascular endothelial growth factor (VEGF) treatment in neovascular age-related macular degeneration (NV-AMD). METHODS: We reviewed the medical records of patients with treatment-naive NV-AMD who underwent three or more consecutive anti-VEGF injections. The patients were divided into three groups according to their changes of visual acuity (VA); improved (group I), static (group S), or worsened (group W). We assessed the incidences and values of all available SD-OCT findings of these groups, compared these findings between the three groups and compared the initial values with the post-treatment values. RESULTS: Better initial VA and longer external limiting membrane (ELM) length were associated with less change in VA after anti-VEGF treatment. The initial VA was mildly correlated with initial photoreceptor inner and outer segment junction (IS/OS) length and initial ELM length. The final VA was also mildly correlated with the final IS/OS length and the final ELM length. VA was significantly changed after anti-VEGF treatment in groups W and I. With regard to incidence, disruption of the IS/OS (IS/OS-D), disruption of the ELM (ELM-D) and ELM length differed significantly between the three groups, particularly ELM-D. The incidences of IS/OS-D and ELM-D in group I were significantly lower than those in groups S and W, and those in group S were also lower than those in group W. The ELM length in group I was significantly longer than it was in groups S and W, and the ELM length in group S was longer than that for group W. However, these three findings did not change after the anti-VEGF treatment. CONCLUSIONS: Initial IS/OS-D, ELM length and particularly ELM-D can be useful predictors of the visual outcome after anti-VEGF treatment in NV-AMD patients.
Aged ; Aged, 80 and over ; Angiogenesis Inhibitors/*therapeutic use ; Choroidal Neovascularization/*drug therapy/physiopathology ; Female ; Humans ; Intravitreal Injections ; Male ; Middle Aged ; Ranibizumab/*therapeutic use ; Retinal Photoreceptor Cell Inner Segment/pathology ; Retinal Photoreceptor Cell Outer Segment/pathology ; Tomography, Optical Coherence ; Vascular Endothelial Growth Factor A/antagonists & inhibitors ; Visual Acuity/*physiology ; Wet Macular Degeneration/*drug therapy/physiopathology

PURPOSE: To evaluate the efficacy of anti-vascular endothelial growth factor (VEGF) compared with observation for treating acute central serous chorioretinopathy (CSC). METHODS: A retrospective study of 36 patients with acute CSC, including 21 patients treated with anti-VEGF (anti-VEGF group) and 15 patients with observation (observation group). Patients in the anti-VEGF group received a single dose of bevacizumab or ranibizumab at baseline. Best-corrected visual acuity (BCVA), central foveal thickness (CFT) and resolution of subretinal fluid (SRF) on optical coherence tomography (OCT) were assessed. The integrity of the foveal inner segment/outer segment (IS/OS) line at 12 months was also analyzed. RESULTS: Resolution of SRF was achieved in 20 of 21 eyes in the anti-VEGF group and in 12 of 15 eyes in the observation group (p = 0.151). Mean BCVA and CFT were not different between the two groups at 12 months (p > 0.05). The amount of change in BCVA, however, differed significantly between the groups (p = 0.044). Final OCT more frequently detected the foveal IS/OS line in the anti-VEGF group than in the observation group (p = 0.012). CONCLUSIONS: In terms of BCVA, anti-VEGF and observation only had similar therapeutic effects in acute CSC patients. In some patients, however, the rapid resolution of SRF by anti-VEGF might reduce the risk of photoreceptor degeneration and improve long-term visual acuity.
Acute Disease ; Adult ; Angiogenesis Inhibitors/*therapeutic use ; Bevacizumab/therapeutic use ; Central Serous Chorioretinopathy/*drug therapy/physiopathology ; Female ; Humans ; Intravitreal Injections ; Male ; Middle Aged ; Observation ; Ranibizumab/therapeutic use ; Retinal Photoreceptor Cell Inner Segment/pathology ; Retinal Photoreceptor Cell Outer Segment/pathology ; Retrospective Studies ; Subretinal Fluid/drug effects ; Tomography, Optical Coherence ; Vascular Endothelial Growth Factor A/antagonists & inhibitors ; Visual Acuity