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Marangoz D, Guzel E, Eyuboglu S, Gumusel A, Seckin I, Ciftci F, Yilmaz B, Yalvac I. Comparison of the neuroprotective effects of brimonidine tartrate and melatonin on retinal ganglion cells. Int Ophthalmol 2017; 38:2553-2562. [PMID: 29159432 DOI: 10.1007/s10792-017-0768-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 11/12/2017] [Indexed: 02/07/2023]
Abstract
PURPOSE We aimed to compare the neuroprotective effects of brimonidine tartrate (BRT) and melatonin (MEL) on retinal ganglion cells (RGCs) in a rat glaucoma model. METHODS Thirty-six adult Wistar albino rats were allocated into six groups: control (C), glaucoma (G), BRT, MEL, G + BRT and G + MEL. After establishing the glaucoma model, intraocular pressure (IOP) of all animals measured at day 4 and day 30 was compared statistically with day 0 and day 4, respectively. Prior to sacrification at day 30 for histological evaluation and TUNEL analysis, retrograde labeling of non-apoptotic RGCs with 3% Fluorogold was performed and RGCs were evaluated under fluorescein microscope. RESULTS IOP measurements at day 4 were significantly higher than basal measurements in all glaucoma groups. BRT alone induced a time-dependent decrease in IOP (p < 0.05), while MEL alone failed to reduce IOP. However, both BRT and MEL reduced IOP in the presence of glaucoma at day 30 (p < 0.05). BRT treatment significantly reversed the reduced non-apoptotic RGC counts (p < 0.01) and increased TUNEL-positive RGCs (p < 0.001) to control group levels in the presence of glaucoma. However, no statistical significance was found between groups G and G + MEL considering 3% Fluorogold-labeled cell counts and apoptotic index values. CONCLUSION Our study revealed that systemic administration of BRT also has an IOP reducing effect. MEL has no neuroprotective effect on RGCs; on the other hand, BRT acts as a neuroprotective agent against glaucomatous injury, when applied systemically.
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Affiliation(s)
- Deniz Marangoz
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey.
| | - Elif Guzel
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey.
| | - Signem Eyuboglu
- Department of Physiology, Faculty of Medicine, Yeditepe University, Inonu mah. Kayisdagi cad. 26 Agustos Yerleskesi, 34755, Istanbul, Turkey
| | - Asli Gumusel
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey
| | - Ismail Seckin
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey
| | - Ferda Ciftci
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey
| | - Bayram Yilmaz
- Department of Physiology, Faculty of Medicine, Yeditepe University, Inonu mah. Kayisdagi cad. 26 Agustos Yerleskesi, 34755, Istanbul, Turkey
| | - Ilgaz Yalvac
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey
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Toler SM. Oxidative Stress Plays an Important Role in the Pathogenesis of Drug-Induced Retinopathy. Exp Biol Med (Maywood) 2016; 229:607-15. [PMID: 15229354 DOI: 10.1177/153537020422900704] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Several pharmaceutical agents have been associated with rare but serious retinopathies, some resulting in blindness. Little is known of the mechanism(s) that produce these injuries. Mechanisms proposed thus far have not been embraced by the medical and scientific communities. However, preclinical and clinical data indicate that oxidative stress may contribute substantially to iatrogenic retinal disease. Retinal oxidative stress may be precipitated by the interaction of putative retinal toxins with the ocular redox system. The retina, replete with cytochromes P450 and myeloperoxidase, may serve to activate xenobiotics to oxidants, resulting in ocular injury. These activated agents may directly form retinal adducts or may diminish ocular reduced glutathione concentrations. Data are reviewed that suggest that indomethacin, tamoxifen, thioridazine, and chloroquine all produce retinopathies via a common mechanism—they produce ocular oxidative stress.
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Affiliation(s)
- Steven M Toler
- Clinical Safety and Risk Management, Pfizer Inc., Pfizer Global Research and Development, 50 Pequot Avenue, New London, CT 06320, USA.
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Melatonin in Retinal Physiology and Pathology: The Case of Age-Related Macular Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6819736. [PMID: 27688828 PMCID: PMC5027321 DOI: 10.1155/2016/6819736] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/09/2016] [Indexed: 12/16/2022]
Abstract
Melatonin, an indoleamine, is synthesized mainly in the pineal gland in a circadian fashion, but it is produced in many other organs, including the retina, which seems to be especially important as the eye is a primary recipient of circadian signals. Melatonin displays strong antioxidative properties, which predispose it to play a protective role in many human pathologies associated with oxidative stress, including premature aging and degenerative disease. Therefore, melatonin may play a role in age-related macular degeneration (AMD), a disease affecting photoreceptors, and retinal pigment epithelium (RPE) with an established role of oxidative stress in its pathogenesis. Several studies have shown that melatonin could exert the protective effect against damage to RPE cells evoked by reactive oxygen species (ROS), but it has also been reported to increase ROS-induced damage to photoreceptors and RPE. Melatonin behaves like synthetic mitochondria-targeted antioxidants, which concentrate in mitochondria at relatively high levels; thus, melatonin may prevent mitochondrial damage in AMD. The retina contains telomerase, an enzyme implicated in maintaining the length of telomeres, and oxidative stress inhibits telomere synthesis, while melatonin overcomes this effect. These features support considering melatonin as a preventive and therapeutic agent in the treatment of AMD.
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Choi YS, Lee MC, Kim HS, Lee KH, Park YG, Kim HK, Jeong HS, Kim MK, Woo YJ, Kim SU, Ryu JK, Choi HB. Neurotoxicity screening in a multipotent neural stem cell line established from the mouse brain. J Korean Med Sci 2010; 25:440-8. [PMID: 20191045 PMCID: PMC2826742 DOI: 10.3346/jkms.2010.25.3.440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Accepted: 05/04/2009] [Indexed: 12/16/2022] Open
Abstract
Neural stem cells (NSCs) have mainly been applied to neurodegeneration in some medically intractable neurologic diseases. In this study, we established a novel NSC line and investigated the cytotoxic responses of NSCs to exogenous neurotoxicants, glutamates and reactive oxygen species (ROS). A multipotent NSC line, B2A1 cells, was established from long-term primary cultures of oligodendrocyte-enriched cells from an adult BALB/c mouse brain. B2A1 cells could be differentiated into neuronal, astrocytic and oligodendroglial lineages. The cells also expressed genotypic mRNA messages for both neural progenitor cells and differentiated neuronoglial cells. B2A1 cells treated with hydrogen peroxide and L-buthionine-(S,R)-sulfoximine underwent 30-40% cell death, while B2A1 cells treated with glutamate and kainate showed 25-35% cell death. Cytopathologic changes consisting of swollen cell bodies, loss of cytoplasmic processes, and nuclear chromatin disintegration, developed after exposure to both ROS and excitotoxic chemicals. These results suggest that B2A1 cells may be useful in the study of NSC biology and may constitute an effective neurotoxicity screening system for ROS and excitotoxic chemicals.
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Affiliation(s)
- Yong-Soo Choi
- Department of Pathology, Chonnam National University Medical School, Gwangju, Korea
| | - Min-Cheol Lee
- Department of Pathology, Chonnam National University Medical School, Gwangju, Korea
- Center for Biomedical Human Resources (BK 21), Chonnam National University Medical School, Gwangju, Korea
| | - Hyung-Seok Kim
- Department of Forensic Medicine and Pathology, Chonnam National University Medical School, Gwangju, Korea
- Center for Biomedical Human Resources (BK 21), Chonnam National University Medical School, Gwangju, Korea
| | - Kyung-Hwa Lee
- Department of Pathology, Seonam University College of Medicine, Namwon, Korea
| | - Yeoung-Geol Park
- Department of Ophthalmology, Chonnam National University Medical School, Gwangju, Korea
| | - Hyun-Kyung Kim
- Department of Ophthalmology, Chonnam National University Medical School, Gwangju, Korea
| | - Han-Seong Jeong
- Center for Biomedical Human Resources (BK 21), Chonnam National University Medical School, Gwangju, Korea
- Department of Physiology, Chonnam National University Medical School, Gwangju, Korea
| | - Myeong-Kyu Kim
- Department of Neurology, Chonnam National University Medical School, Gwangju, Korea
| | - Young-Jong Woo
- Department of Pediatrics, Chonnam National University Medical School, Gwangju, Korea
| | - Seung-Up Kim
- Department of Neurobiology, Chung-Ang University Medical Center, Seoul, Korea
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jae-Kyu Ryu
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Hyun-Beom Choi
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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Xu S, Zhou Z, Zhang L, Yu Z, Zhang W, Wang Y, Wang X, Li M, Chen Y, Chen C, He M, Zhang G, Zhong M. Exposure to 1800 MHz radiofrequency radiation induces oxidative damage to mitochondrial DNA in primary cultured neurons. Brain Res 2009; 1311:189-96. [PMID: 19879861 DOI: 10.1016/j.brainres.2009.10.062] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 10/22/2009] [Accepted: 10/24/2009] [Indexed: 01/18/2023]
Abstract
Increasing evidence indicates that oxidative stress may be involved in the adverse effects of radiofrequency (RF) radiation on the brain. Because mitochondrial DNA (mtDNA) defects are closely associated with various nervous system diseases and mtDNA is particularly susceptible to oxidative stress, the purpose of this study was to determine whether radiofrequency radiation can cause oxidative damage to mtDNA. In this study, we exposed primary cultured cortical neurons to pulsed RF electromagnetic fields at a frequency of 1800 MHz modulated by 217 Hz at an average special absorption rate (SAR) of 2 W/kg. At 24 h after exposure, we found that RF radiation induced a significant increase in the levels of 8-hydroxyguanine (8-OHdG), a common biomarker of DNA oxidative damage, in the mitochondria of neurons. Concomitant with this finding, the copy number of mtDNA and the levels of mitochondrial RNA (mtRNA) transcripts showed an obvious reduction after RF exposure. Each of these mtDNA disturbances could be reversed by pretreatment with melatonin, which is known to be an efficient antioxidant in the brain. Together, these results suggested that 1800 MHz RF radiation could cause oxidative damage to mtDNA in primary cultured neurons. Oxidative damage to mtDNA may account for the neurotoxicity of RF radiation in the brain.
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Affiliation(s)
- Shangcheng Xu
- Department of Occupational Health, Third Military Medical University, No 30 Gaotanyan Street, Shapingba District, Chongqing 400038, People's Republic of China
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Cruz A, Túnez I, Martínez R, Muñoz-Castañeda JR, Ramírez LM, Recio M, Ochoa L, Arjona A, Montilla P, Muntané J, Padillo FJ. Melatonin prevents brain oxidative stress induced by obstructive jaundice in rats. J Neurosci Res 2008; 85:3652-6. [PMID: 17671989 DOI: 10.1002/jnr.21436] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of the study was to analyze the impact of melatonin on brain oxidative stress in experimental biliary obstruction. Cholestasis was done by a double ligature and section of the extrahepatic biliary duct. Melatonin was injected intraperitoneally (500 microg/kg/day). Malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) contents were determined in the brain tissue. Biliary obstruction raised MDA and reduced GSH contents in the cortex, cerebellum, and hypothalamus areas. Moreover, the scavenger enzyme activity significantly dropped in all areas of the brain. Melatonin drastically reduced MDA concentration and enhanced GSH concentration, as well as all antioxidant enzyme activity in all brain areas obtained from the bile duct-ligated animals. In conclusion, the treatment with melatonin decreased lipid peroxidation and recovered the antioxidant status in the brain from cholestatic animals.
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Affiliation(s)
- Adolfo Cruz
- Department of General Surgery, Reina Sofía University Hospital, Avenida Menendez Pidal s/n, Córdoba, Spain
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Abstract
Recently, fluphenazine, a phenothiazine neuroleptic, has been associated with idiosyncratic retinopathy. Neuroleptic-induced retinopathy appears to be isolated to only a few structurally related phenothiazines, suggesting that the causality is not the result of dopamine antagonism. The chemical structure of fluphenazine is very similar to that of chlorpromazine and thioridazine, agents known to produce retinopathy. Like chlorpromazine and thioridazine, fluphenazine may be oxidized by retinal cytochrome P450 and/or myeloperoxidase to an electrophile, producing injury in susceptible patients.
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Affiliation(s)
- Steven M Toler
- Clinical Pharmacology, Pfizer Global Research and Development, Pfizer Inc., New London, CT 06320, USA.
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Abstract
The circadian rhythm of the chick electroretinogram (ERG) is regulated by the indoleamine hormone melatonin. To determine if the concentration of melatonin or the time at which it was administered would have differential effects on ERG parameters, we conducted experiments analyzing the effects of melatonin at different times of the day. Circadian rhythms of a- and b-wave implicit times and amplitudes were observed in both light:dark (LD) and in continuous darkness (DD). Intramuscular melatonin administration of 1 mg/kg and 100 ng/kg decreased a- and b-wave amplitudes and increased a- and b-wave implicit times. This effect was significantly greater than that observed for 1 ng/kg melatonin, which had little to no effect over the saline controls. The effect of 1 mg/kg and 100 ng/kg melatonin on a- and b-wave amplitude in LD and on b-wave amplitude in DD was greater during the night (ZT/CT 17) than during the day (ZT/CT 5). The fold change in b-wave implicit time over that of controls was greater during the day (ZT/CT 5) than during the night (ZT/CT 17). These data indicate that melatonin may play a role in regulating a day and night functional shift in the retina, and that it does so via regulation of a retinal clock.
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Affiliation(s)
- Jennifer L Peters
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA
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Funakoshi T, Miyata H, Imoto T, Arai T, Endo N, Makino K, Yang CH, Ohama E. 6-Formylpterin protects retinal neurons from transient ischemia-reperfusion injury in rats: a morphological and immunohistochemical study. Neuropathology 2003; 23:161-8. [PMID: 14570282 DOI: 10.1046/j.1440-1789.2003.00493.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neuroprotective effects of 6-formylpterin (6FP) on transient retinal ischemia-reperfusion injury were evaluated in rats by means of counting the number of retinal ganglion cells, measuring the thicknesses of the inner plexiform and inner nuclear layers, and by immunohistochemical detection of apoptotic cells in the retina. Sixty-one Sprague-Dawley rats (12 weeks, male, 295-330 g) were subjected to transient retinal ischemia-reperfusion by elevated intra-ocular pressure (80 mmHg for 60 min). Intraperitoneal injection of 6FP (3.8 mg/kg) was performed before or after ischemia. The retina was histologically better preserved in rats with 6FP treatment than without 6FP treatment. 6FP showed more strong neuroprotective effects when it was administered before ischemia. The number of single-stranded DNA-positive cells in the retina also decreased remarkably in rats with 6FP treatment, especially when administered before ischemia. These results suggest that 6FP protects retinal neurons from transient ischemia-reperfusion injury, at least in part by inhibiting apoptotic cell death.
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Affiliation(s)
- Taisaku Funakoshi
- Divisione of Ophthalmology and Visual Science, Department of Medicine of Sensory and Motor Organs, Faculty of Medicine, Tottori University, Yonago, Japan
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