OBJECTIVETo gain insight into the potential mechanism of mitochondria dysfunction in pathogenesis, progression and therapeutic management of glaucoma.

DATA SOURCESThe data used in this review were mainly published in English from 2000 to present obtained from PubMed. The search terms were "mitochondria", "glaucoma" and "trabecular meshwork" or "retinal ganglion cells".

STUDY SELECTIONArticles studying the mitochondria-related pathologic mechanism and treatment of glaucoma were selected and reviewed.

RESULTSMitochondrial dysfunction or injury was demonstrated in different eye tissue of glaucoma. A variety of potential injuries (light, toxic materials, oxidative injury, mechanical stress, aging, etc.) and the inherent DNA defects are deemed to cause mitochondrial structural and functional destruction in trabecular meshwork cells, retinal ganglion cells, etc. of glaucoma. In addition, various new experimental and therapeutic interventions were used to preserve mitochondrial function, which may be useful for protecting against optic nerve degeneration or reducing the death of retinal ganglion cells in glaucoma.

CONCLUSIONSMitochondria play an important role in the pathogenesis of glaucoma, various strategies targeting mitochondrial protection might provide a promising way to delay the onset of glaucoma or protect RGCs against glaucomatous damage.

Glaucoma ; metabolism ; pathology ; Humans ; Mitochondria ; metabolism ; Retinal Ganglion Cells ; metabolism ; Trabecular Meshwork ; metabolism

In order to elucidate in vivo neuronal cell death in the retina, and involvement of NF-kappa B in this process, we studied the degeneration of retinal ganglion cells (RGCs) and the activation of NF-kappa B after transection of the optic nerve of adult rat at 5 mm from the eyeball. The morphology of dying ganglion cells in the retinal ganglion cell layer was observed by light and electron microscopy, the activation of NF-kappa B was investigated immunohistochemically. Seven and 14 days post-axotomy, dying cells contained pyknotic nuclei. The death of retinal ganglion cells involved apoptosis, activation of NF-kappa B (p50 and p65) was prominent in a time dependent manner. We observed axotomy-induced NF-kappa B activation, which may mediate apoptosis of retinal ganglion cells.
Animal ; Apoptosis/physiology ; Axotomy ; Immunohistochemistry ; Male ; Microscopy, Electron ; NF-kappa B/biosynthesis* ; Optic Nerve/surgery ; Rats ; Rats, Sprague-Dawley ; Retinal Ganglion Cells/ultrastructure ; Retinal Ganglion Cells/pathology* ; Retinal Ganglion Cells/metabolism ; Substances: NF-kappa B

BACKGROUNDCollapsin response mediator protein-2 (CRMP2) has been shown to be involved in ischemia/hypoxia (IH) injury. We determined whether CRMP2 modulates ischemic injury in the retinal of Ocular ischemic syndrome (OIS). This study was to explore the molecular mechanisms underlying OIS in a novel mice model.

METHODSExperiments were performed on adult male C57/BL6 mice that received bilateral internal carotid arteries ligation for 1, 2, or 4 weeks. The mice received injection of calpeptin group before occlusion for 4 weeks or not. The expression of CRMP2 in the retinal was examined by western blotting (WB) analysis and immunohistochemical analysis (IHC). The effects of ischemic injury on retinal were evaluated by fundus examination, fundus fluorescein angiography, electroretinogram, cell counting of retinal ganglion cell (RGC), and measurement of the thickness of the retina.

RESULTSThe veins dilated after chronic ischemia. In the electroretinography, the amplitudes of a- and b-waves kept diminishing in an ischemia time-dependent manner. Moreover, the tail vein-retinal circulation time prolonged in the 1- and 2-week group. In comparison, thickness of the retina decreased gradually with the ischemia time elapsed. WB analysis showed the CRMP2 and p-CRMP2 levels decreased in the 2- and 4-week groups. The results of IHC analysis were compatible with our results of WB. The loss of RGCs, decrease of the total reaction time and reduction of CRMP2 was alleviated by intravitreal injection of calpeptin.

CONCLUSIONSThese results revealed that bilateral ligation of the internal carotid artery causes retinal ischemia in mice. Moreover, CRMP2 might play a pivotal role during the ischemic injury in the retina and inhibit the cleavage of CRMP2 can ameliorate the IH injury.

Animals ; Disease Models, Animal ; Electroretinography ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; Ischemia ; genetics ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins ; genetics ; metabolism ; Retinal Diseases ; genetics ; metabolism ; pathology ; Retinal Ganglion Cells ; metabolism ; pathology

PURPOSE: To assess whether the expression of heat shock protein 72 (Hsp72) protects rat retinal ganglion cells (RGC-5) from apoptotic cell death. METHODS: Hsp72 expression in RGC-5 cells transduced with replication-deficient recombinant adenovirus was analyzed by Western blot analysis and immunofluorescence. The effect of Hsp72 expression on etoposide-induced apoptotic cell death was examined by microscopic analysis and confirmed by cell proliferation assay. RESULTS: Western blot analysis and immunofluorescence clearly showed adenovirus-mediated Hsp72 expression in RGC-5 cells. Treatment with etoposide resulted in the death of a proportion of the cells by apoptosis. However, this apoptotic cell death was significantly reduced in cells expressing Hsp72, with the reduction in cell death correlating to the level of Hsp72 expression. CONCLUSIONS: Over-expression of Hsp72 alone is sufficient to rescue neuronal cells from apoptotic cell death, suggesting that fine-tuning its expression may be an effective neuroprotective approach in retinal degenerative disease.
Animals ; Blotting, Western ; Cell Death/*genetics ; Cell Survival ; Cells, Cultured ; DNA/*genetics ; Disease Models, Animal ; Etoposide/toxicity ; *Gene Expression Regulation ; HSP72 Heat-Shock Proteins/biosynthesis/*genetics ; Immunohistochemistry ; Rats ; Retinal Degeneration/*genetics/metabolism/pathology ; Retinal Ganglion Cells/drug effects/*metabolism/pathology

The purpose of this study was to investigate the effect of inhibition of calpain on retinal ganglion cell-5 (RGC-5) necroptosis following oxygen glucose deprivation (OGD). RGC-5 cells were cultured in Dulbecco's-modified essential medium and necroptosis was induced by 8-h OGD. PI staining and flow cytometry were performed to detect RGC-5 necrosis. The calpain expression was detected by Western blotting and immunofluorescence staining. The calpain activity was tested by activity detection kit. Flow cytometry was used to detect the effect of calpain on RGC-5 necroptosis following OGD with or without N-acetyl-leucyl-leucyl-norleucinal (ALLN) pre-treatment. Western blot was used to detect the protein level of truncated apoptosis inducing factor (tAIF) in RGC-5 cells following OGD. The results showed that there was an up-regulation of the calpain expression and activity following OGD. Upon adding ALLN, the calpain activity was inhibited and tAIF was reduced following OGD along with the decreased number of RGC-5 necroptosis. In conclusion, calpain was involved in OGD-induced RGC-5 necroptosis with the increased expression of its downstream molecule tAIF.
Animals ; Apoptosis Inducing Factor ; biosynthesis ; genetics ; Calpain ; biosynthesis ; genetics ; Gene Expression Regulation ; drug effects ; Glucose ; metabolism ; Humans ; Leupeptins ; administration & dosage ; Mice ; Oxygen ; metabolism ; Retinal Ganglion Cells ; metabolism ; pathology ; Retinal Necrosis Syndrome, Acute ; genetics ; pathology

PURPOSE: To evaluate the expression of the Na(+)-K(+)-2Cl(-)-cotransporter 2 (NKCC2) in the ischemic rat retina. METHODS: Retinal ischemia was induced by pressures 90 to 120 mmHg, above systemic systolic pressure. Immunohistochemistry and western blot analysis were performed. RESULTS: NKCC2 is expressed in the normal retina and its expression is increased by ischemia caused by intraocular pressure elevation. NKCC2 immunoreactivity was observed mainly in axon bundles of ganglion cells and horizontal cell processes in the retina. NKCC2 expression continuously increased with a peak value 3 days (to 415% of normal levels) after ischemic injury, and then gradually decreased to 314% of controls until 2 weeks post injury. The mean density of NKCC2-labeled ganglion cells per mm2 changed from 1,255 +/- 109 in normal retinas to 391 +/- 49 and 185 +/- 37 at 3 days and 2 weeks after ischemia, respectively (p < 0.05), implying cell death of ganglion cells labeled with NKCC2. CONCLUSIONS: Taken together, these results suggest that NKCC2, which is expressed in retinal ganglion and horizontal cells, may contribute to cell death by ischemic injury in the retina, although the molecular mechanisms involved remain to be clarified.
Animals ; Blotting, Western ; Disease Models, Animal ; Immunohistochemistry ; Intraocular Pressure ; Ischemia/etiology/*metabolism ; Male ; Microscopy, Confocal ; Ocular Hypertension/*complications/metabolism/physiopathology ; Rats ; Rats, Sprague-Dawley ; Retinal Diseases/etiology/*metabolism ; Retinal Ganglion Cells/*metabolism/pathology ; Sodium-Potassium-Chloride Symporters/*biosynthesis

Apoptosis ; Extracellular Matrix Proteins ; metabolism ; Glaucoma ; pathology ; Glutamic Acid ; metabolism ; Humans ; Neuroglia ; pathology ; physiology ; Nitric Oxide Synthase ; physiology ; Optic Nerve ; physiology ; Optic Nerve Diseases ; pathology ; Retinal Ganglion Cells ; pathology ; Tumor Necrosis Factor-alpha ; physiology

PURPOSE: Maltol (3-hydroxy-2-methyl-4-pyrone), formed by the thermal degradation of starch, is found in coffee, caramelized foods, and Korean ginseng root. This study investigated whether maltol could rescue neuroretinal cells from oxidative injury in vitro. METHODS: R28 cells, which are rat embryonic precursor neuroretinal cells, were exposed to hydrogen peroxide (H2O2, 0.0 to 1.5 mM) as an oxidative stress with or without maltol (0.0 to 1.0 mM). Cell viability was monitored with the lactate dehydrogenase assay and apoptosis was examined by the terminal deoxynucleotide transferase-mediated terminal uridine deoxynucleotidyl transferase nick end-labeling (TUNEL) method. To investigate the neuroprotective mechanism of maltol, the expression and phosphorylation of nuclear factor-kappa B (NF-kappaB), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 were evaluated by Western immunoblot analysis. RESULTS: R28 cells exposed to H2O2 were found to have decreased viability in a dose- and time-dependent manner. However, H2O2-induced cytotoxicity was decreased with the addition of maltol. When R28 cells were exposed to 1.0 mM H2O2 for 24 hours, the cytotoxicity was 60.69 ± 5.71%. However, the cytotoxicity was reduced in the presence of 1.0 mM maltol. This H2O2-induced cytotoxicity caused apoptosis of R28 cells, characterized by DNA fragmentation. Apoptosis of oxidatively-stressed R28 cells with 1.0 mM H2O2 was decreased with 1.0 mM maltol, as determined by the TUNEL method. Western blot analysis showed that treatment with maltol reduced phosphorylation of NF-kappaB, ERK, and JNK, but not p38. The neuroprotective effects of maltol seemed to be related to attenuated expression of NF-kappaB, ERK, and JNK. CONCLUSIONS: Maltol not only increased cell viability but also attenuated DNA fragmentation. The results obtained here show that maltol has neuroprotective effects against hypoxia-induced neuroretinal cell damage in R28 cells, and its effects may act through the NF-kappaB and mitogen-activated protein kinase signaling pathways.
Animals ; *Apoptosis ; Blotting, Western ; Cell Survival ; Cells, Cultured ; Disease Models, Animal ; Flavoring Agents/pharmacology ; In Situ Nick-End Labeling ; Oxidative Stress/*drug effects ; Pyrones/*pharmacology ; Rats ; Retinal Ganglion Cells/drug effects/metabolism/*pathology

OBJECTIVE: To observe the change of retinal ganglion cells (RGCs)and the expression of Bad after optic nerve injury, so as to study the changes of optic function level on morphology and molecular. METHODS: The experimental models of optic nerve crush were established in fifty Wistar rats. At the different time after injuries (from one to twenty-eight day), the changes of RGCs were observed under microscope. Immunohistochemiscal technique and computer image analysis methods were performed to observe the changes of Bad in RGCs in rats. RESULTS: The number of RGCs was reduced significantly according to partial lesion of optic nerve crush. An initial loss of RGCs densities was accelerated in one week after nerve crush, two weeks later the trend mitigated. After four weeks, no obvious change were observed. The expression of Bad increased in 3 days, reached peak in 5 days, and declined one week later. No obvious changes were observed after two weeks. CONCLUSION The expression of Bad lead to the loss of RGCs following optic nerve crush. This is the important reason of loss optic function. The identification on optic nerve injuries should be done at least four weeks later.
Animals ; Cell Death ; Disease Models, Animal ; Female ; Forensic Medicine ; Male ; Nerve Crush ; Optic Nerve/physiopathology* ; Optic Nerve Injuries/pathology* ; Random Allocation ; Rats ; Rats, Wistar ; Retinal Ganglion Cells/pathology* ; Time Factors ; bcl-Associated Death Protein/metabolism*