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Sánchez-Fernández C, Del Olmo-Aguado S, Artime E, Barros A, Fernández-Vega Cueto L, Merayo-Lloves J, Alcalde I. Immunocytochemical Analysis of Crocin against Oxidative Stress in Trigeminal Sensory Neurons Innervating the Cornea. Molecules 2024; 29:456. [PMID: 38257369 PMCID: PMC10818698 DOI: 10.3390/molecules29020456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/15/2023] [Accepted: 01/15/2024] [Indexed: 01/24/2024] Open
Abstract
Corneal diseases are a major cause of vision loss, often associated with aging, trauma and disease. Damage to corneal sensory innervation leads to discomfort and pain. Environmental stressors, such as short-wavelength light, can induce oxidative stress that alters mitochondrial function and affects cell and tissue homeostasis, including corneal innervation. Cellular antioxidant mechanisms may attenuate oxidative stress. This study investigates crocin, a derivative of saffron, as a potential antioxidant therapy. In vitro rat trigeminal sensory ganglion neurons were exposed to both sodium azide and blue light overexposure as a model of oxidative damage. Crocin was used as a neuroprotective agent. Mitochondrial and cytoskeletal markers were studied by immunofluorescence analysis to determine oxidative damage and neuroprotection. In vivo corneal innervation degeneration was evaluated in cornea whole mount preparations using Sholl analyses. Blue light exposure induces oxidative stress that affects trigeminal neuron mitochondria and alters sensory axon dynamics in vitro, and it also affects corneal sensory innervation in an in vivo model. Our results show that crocin was effective in preserving mitochondrial function and protecting corneal sensory neurons from oxidative stress. Crocin appears to be a promising candidate for the neuroprotection of corneal innervation.
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Affiliation(s)
- Cristina Sánchez-Fernández
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Susana Del Olmo-Aguado
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Enol Artime
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Alberto Barros
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
| | - Luis Fernández-Vega Cueto
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Jesús Merayo-Lloves
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Ignacio Alcalde
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, 33012 Oviedo, Spain; (C.S.-F.); (S.D.O.-A.); (E.A.); (A.B.); (L.F.-V.C.); (J.M.-L.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
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Hecht I, Kanclerz P, Achiron A, Elbaz U, Tuuminen R. The Effect of Blue-Light Filtering Intraocular Lenses on the Development and Progression of Glaucoma. J Glaucoma 2023; 32:451-457. [PMID: 37054398 DOI: 10.1097/ijg.0000000000002220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 03/09/2023] [Indexed: 04/15/2023]
Abstract
PRCIS Among patients who underwent uneventful cataract surgery, an advantage was seen to blue-light filtering (BLF) intraocular lenses (IOLs) in terms of glaucoma-free survival and glaucoma procedure-free survival. Among patients with preexisting glaucoma, no advantage was seen. PURPOSE To assess the effect of BLF IOLs on the development and progression of glaucoma after cataract surgery. PATIENTS AND METHODS A retrospective cohort study of patients who underwent uneventful cataract surgery between 2007 and 2018 at Kymenlaakso Central Hospital, Finland. Survival analyses for the overall risk of developing glaucoma or undergoing glaucoma procedures were assessed between patients who received a BLF IOL (SN60WF) and a non-BLF IOL (ZA9003 and ZCB00). A separate analysis was performed on patients with preexisting glaucoma. RESULTS Included 11,028 eyes of 11,028 patients with a mean age of 75 ± 9 years (62% females). The BLF IOL was used in 5188 eyes (47%) and the non-BLF IOL in 5840 eyes (53%). During the follow-up (mean: 55 ± 34 mo), 316 cases of glaucoma were diagnosed. Glaucoma-free survival rates showed an advantage to the BLF IOL ( P = 0.036). In a Cox regression analysis controlling for age and sex the use of a BLF IOL was again associated with a lower ratio of glaucoma development (hazard ratio:0.778; 95% CI: 0.621-0.975). Furthermore, glaucoma procedure-free survival analysis revealed an advantage to the BLF IOL (hazard ratio:0.616; 95% CI: 0.406-0.935). Among 662 cases, which already had glaucoma at the time of surgery, no significant differences were seen in any outcome. CONCLUSIONS Among a large cohort of patients who underwent cataract surgery, the use of BLF IOLs was associated with favorable glaucoma outcomes compared with the use of non-BLF IOLs. Among patients with preexisting glaucoma, no significant advantage was seen.
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Affiliation(s)
- Idan Hecht
- Helsinki Retina Research Group, University of Helsinki, Helsinki
- Sackler School of Medicine, Tel Aviv University
- Department of Ophthalmology, Shamir Medical Center
| | - Piotr Kanclerz
- Helsinki Retina Research Group, University of Helsinki, Helsinki
- Hygeia Clinic, Gdańsk, Poland
| | - Asaf Achiron
- Sackler School of Medicine, Tel Aviv University
- Tel Aviv Sourasky Medical Center, Tel Aviv
| | - Uri Elbaz
- Sackler School of Medicine, Tel Aviv University
- Department of Ophthalmology, Rabin Medical Center, Petach Tikva, Israel
| | - Raimo Tuuminen
- Helsinki Retina Research Group, University of Helsinki, Helsinki
- Department of Ophthalmology, Kymenlaakso Central Hospital, Kotka, Finland
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Ziółkowska N, Lewczuk B, Szyryńska N, Rawicka A, Vyniarska A. Low-Intensity Blue Light Exposure Reduces Melanopsin Expression in Intrinsically Photosensitive Retinal Ganglion Cells and Damages Mitochondria in Retinal Ganglion Cells in Wistar Rats. Cells 2023; 12:cells12071014. [PMID: 37048087 PMCID: PMC10093228 DOI: 10.3390/cells12071014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/18/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023] Open
Abstract
This study investigated the effect of low-intensity blue light on the albino Wistar rat retina, including intrinsically photosensitive retinal ganglion cells (ipRGCs). Three groups of nine albino Wistar rats were used. One group was continuously exposed to blue light (150 lx) for 2 d (STE); one was exposed to 12 h of blue light and 12 h of darkness for 10 d (LTE); one was maintained in 12 h of white light (150 lx) and 12 h of darkness for 10 d (control). Melanopsin (Opn4) was immunolabelled on retinal whole-mounts. To count and measure Opn4-positive ipRGC somas and dendrites (including Sholl profiles), Neuron J was used. Retinal cryosections were immunolabeled for glial fibrillary acid protein (GFAP) and with terminal deoxynucleotidyl transferase dUTP nick-end labelling for apoptosis detection. LTE reduced the length of Opn4-positive ipRGC dendrites (p = 0.03) and decreased Opn4-immunoreactivity in ipRGC outer stratifying dendrites. LTE and STE decreased the complexity of dendritic arborization (Sholl profile; p < 0.001, p = 0.03, respectively), increased retinal GFAP immunoreactivity (p < 0.001, p = 0.002, respectively), and caused outer segment vesiculation and outer nuclear layer apoptosis. Ultrastructural analysis showed that LTE damaged mitochondria in retinal ganglion cells and in the inner plexiform layer. Thus, LTE to low-intensity blue light harms the retinas of albino Wistar rats.
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Ziółkowska N, Lewczuk B. Profiles of Rho, Opn4, c-Fos, and Birc5 mRNA expression in Wistar rat retinas exposed to white or monochromatic light. Front Neuroanat 2022; 16:956000. [PMID: 36059433 PMCID: PMC9434339 DOI: 10.3389/fnana.2022.956000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/21/2022] [Indexed: 11/30/2022] Open
Abstract
Despite concern over potential retinal damage linked to exposure to light-emitting-diode (LED) light (particularly blue light), it remains unknown how exposure to low-intensity monochromatic LED light affects the expression of rhodopsin (Rho, a photopigment that mediates light-induced retinal degeneration), melanopsin (Opn4, a blue-light sensitive photopigment), c-Fos (associated with retinal damage/degeneration), and Birc5 (anti-apoptotic). This study investigated the mRNA expression profiles of these genes under exposure to white and monochromatic light (blue, red, green) in the retinas of albino rats under a cycle of 12 h of light and 12 h of darkness. In each group, 32 Wistar rats were exposed to one type of monochromatic-LED or white-fluorescent light for 7 day (150 lx). Retinal samples were taken for qPCR analysis and light and electron microscopy. Blue and green light exposure markedly decreased expression of Rho and Opn4 mRNA and increased expression of Birc5 and c-Fos mRNA (P < 0.05). In retinas from the blue-light group, loss and vesiculation of photoreceptor outer segments were visible, but not in retinas from the red-light and control group. Measurements of the photoreceptor inner and outer segments length revealed, that this length was significantly decreased in the blue- and green-light exposure groups (P < 0.02), but not in the red-light exposure group. Increased expression of Birc5 and decreased expression of Rho and Opn4 after exposure to blue and green light may be early responses that help to reduce light-induced retinal damage.
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Affiliation(s)
- Natalia Ziółkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
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Kanclerz P, Hecht I, Cunha M, Knyazer B, Laine I, Tuuminen R. Association of Blue Light-Filtering Intraocular Lenses With All-Cause and Traffic Accident-Related Injuries Among Patients Undergoing Bilateral Cataract Surgery in Finland. JAMA Netw Open 2022; 5:e2227232. [PMID: 35976646 PMCID: PMC9386539 DOI: 10.1001/jamanetworkopen.2022.27232] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
IMPORTANCE Blue light-filtering (BLF) intraocular lenses (IOLs) have been widely used in clinical practice for more than 20 years and have been implanted in millions of patients with cataracts worldwide. However, little evidence on the association of BLF IOLs with injuries is available. OBJECTIVE To assess the association of BLF IOLs with all-cause and traffic accident-related injuries and quality of vision while driving after bilateral cataract surgery. DESIGN, SETTING, AND PARTICIPANTS This retrospective registry-based cohort study included patients who underwent bilateral cataract surgery between September 3, 2007, and December 14, 2018, and were followed until December 14, 2021. Surgery was performed at the Department of Ophthalmology, Kymenlaakso Central Hospital, Kotka, Finland. The 4986 participants received non-BLF IOLs (n = 2609) or BLF IOLs (n = 2377) in both eyes. Patients undergoing bilateral surgery between 2015 to 2016 with non-BLF IOLs (n = 102) or BLF IOLs (n = 91) and currently driving a car were interviewed using a structured questionnaire for visual performance while driving. EXPOSURES Follow-up for a mean (SD) of 2166 (1110) days after second eye surgery. MAIN OUTCOMES AND MEASURES Kaplan-Meier and multivariable Cox proportional hazards regression analyses for the risk of all-cause and traffic accident-related injuries after surgery in the second eye obtained from the patient medical records were assessed. To improve follow-up precision, both death and the end of the follow-up were used as censoring events. RESULTS A total of 4986 patients were included in the analysis (1707 [34.2%] men and 3279 [65.8%] women; mean [SD] age, 73.2 [8.6] years at the first surgery and 74.3 [8.8] years at the second). Injury-free survival rates preceding the first eye surgery were comparable between the non-BLF and BLF IOL groups (hazard ratio adjusted for age and sex, 0.95 [95% CI, 0.81-1.13; P = .57]). In multivariable Cox proportional hazards regression analysis controlling for age and sex, the use of BLF IOLs showed no advantage in overall injuries compared with the use of non-BLF IOLs (hazard ratio, 0.99 [95% CI, 0.88-1.11]; P = .85) or in any injury subtype. Subjective visual performance parameters for driving were all comparable between the non-BLF and BLF IOL groups except for glare when driving in the dark (evening or night), which occurred among 9 of 80 patients with BLF IOLs compared with 0 of 83 non-BLF IOLs (P < .001). CONCLUSIONS AND RELEVANCE The findings of this cohort study suggest that use of BLF IOLs was not associated with reduced risk of injuries, whereas glare during nighttime driving was significantly worse in the BLF IOL group with pseudophakia.
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Affiliation(s)
- Piotr Kanclerz
- Helsinki Retina Research Group, University of Helsinki, Helsinki, Finland
- Hygeia Clinic, Gdańsk, Poland
| | - Idan Hecht
- Helsinki Retina Research Group, University of Helsinki, Helsinki, Finland
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Shamir Medical Center, Tel Aviv, Israel
| | - Mariana Cunha
- Helsinki Retina Research Group, University of Helsinki, Helsinki, Finland
- Medical School, São Paulo State University, São Paulo, Brazil
| | - Boris Knyazer
- Department of Ophthalmology, Soroka University Medical Center, Beersheba, Israel
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Ilkka Laine
- Helsinki Retina Research Group, University of Helsinki, Helsinki, Finland
- School of Engineering, Aalto University, Helsinki, Finland
| | - Raimo Tuuminen
- Helsinki Retina Research Group, University of Helsinki, Helsinki, Finland
- Department of Ophthalmology, Kymenlaakso Central Hospital, Kotka, Finland
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Ziólkowska N, Chmielewska-Krzesinska M, Vyniarska A, Sienkiewicz W. Exposure to Blue Light Reduces Melanopsin Expression in Intrinsically Photoreceptive Retinal Ganglion Cells and Damages the Inner Retina in Rats. Invest Ophthalmol Vis Sci 2022; 63:26. [PMID: 35060997 PMCID: PMC8787613 DOI: 10.1167/iovs.63.1.26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Purpose The purpose of this study was to investigative the effects of blue light on intrinsically photoreceptive retinal ganglion cells (ipRGCs). Methods Brown Norway rats were used. Nine rats were continuously exposed to blue light (light emitting diodes [LEDs]: 463 nm; 1000 lx) for 2 days (acute exposure [AE]); 9 rats were exposed to 12 hours of blue light and 12 hours of darkness for 10 days (long-term exposure [LTE]); 6 control rats were exposed to 12 hours of white fluorescent light (1000 lx) and 12 hours of darkness for 10 days. Whole-mount retinas were immunolabelled with melanopsin antibodies; melanopsin-positive (MP) ipRGC somas and processes were counted and measured with Neuron J. To detect apoptosis, retinal cryo-sections were stained with terminal deoxynucleotidyl transferase dUTP nick-end labeling. Ultra-thin sections were visualized with transmission electron microscopy. Results The number of MP ipRGC somas was significantly lower in retinas from AE and LTE rats than in those from control rats (P < 0.001 and = 0.002, respectively). The mean length of MP areas of processes was significantly lower in AE rats (P < 0.001). AE rats had severe retinal damage and massive apoptosis in the outer nuclear layer; their mitochondria were damaged in the axons and dendrites of the nerve fiber layer and the inner plexiform layer. Retinal ganglion cells (RGCs) in AE rats appeared to have reduced amounts of free ribosomes and rough endoplasmic reticulum. Conclusions AE to blue light reduces melanopsin expression and damages RGCs, likely including ipRGCs. Changes in the axons and dendrites of RGCs suggest possible disruption of intraretinal and extraretinal signal transmission.
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Affiliation(s)
- Natalia Ziólkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Malgorzata Chmielewska-Krzesinska
- Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Alla Vyniarska
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Stepan Gzhytskyi National University of Veterinary and Biotechnologies, Lviv, Ukraine
| | - Waldemar Sienkiewicz
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
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Kam JH, Hogg C, Fosbury R, Shinhmar H, Jeffery G. Mitochondria are specifically vulnerable to 420nm light in drosophila which undermines their function and is associated with reduced fly mobility. PLoS One 2021; 16:e0257149. [PMID: 34478469 PMCID: PMC8415596 DOI: 10.1371/journal.pone.0257149] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/24/2021] [Indexed: 01/05/2023] Open
Abstract
Increased blue light exposure has become a matter of concern as it has a range of detrimental effects, but the mechanisms remain unclear. Mitochondria absorb short wavelength light but have a specific absorbance at 420nm at the lower end of the human visual range. This 420nm absorption is probably due to the presence of porphyrin. We examine the impact of 420nm exposure on drosophila melanogaster mitochondria and its impact on fly mobility. Daily 15 mins exposures for a week significantly reduced mitochondrial complex activities and increased mitochondrial inner membrane permeability, which is a key metric of mitochondrial health. Adenosine triphosphate (ATP) levels were not significantly reduced and mobility was unchanged. There are multiple options for energy/time exposure combinations, but we then applied single 420nm exposure of 3h to increase the probability of an effect on ATP and mobility, and both were significantly reduced. ATP and mitochondrial membrane permeability recovered and over corrected at 72h post exposure. However, despite this, normal mobility did not return. Hence, the effect of short wavelengths on mitochondrial function is to reduce complex activity and increasing membrane permeability, but light exposure to reduce ATP and to translate into reduced mobility needs to be sustained.
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Affiliation(s)
- Jaimie Hoh Kam
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Chris Hogg
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Robert Fosbury
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Harpreet Shinhmar
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, London, United Kingdom
- * E-mail:
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Le M, McNeill FE, Seymour CB, Rusin A, Diamond K, Rainbow AJ, Murphy J, Mothersill CE. Modulation of oxidative phosphorylation (OXPHOS) by radiation- induced biophotons. ENVIRONMENTAL RESEARCH 2018; 163:80-87. [PMID: 29427954 DOI: 10.1016/j.envres.2018.01.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/21/2018] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
Radiation-induced biophotons are an electromagnetic form of bystander signalling. In human cells, biophoton signalling is capable of eliciting effects in non-irradiated bystander cells. However, the mechanisms by which the biophotons interact and act upon the bystander cells are not clearly understood. Mitochondrial energy production and ROS are known to be involved but the precise interactions are not known. To address this question, we have investigated the effect of biophoton emission upon the function of the complexes of oxidative phosphorylation (OXPHOS). The exposure of bystander HCT116 p53 +/+ cells to biophoton signals emitted from β-irradiated HCT116 p53 +/+ cells induced significant modifications in the activity of Complex I (NADH dehydrogenase or NADH:ubiquinone oxidoreductase) such that the activity was severely diminished compared to non-irradiated controls. The enzymatic assay showed that the efficiency of NADH oxidation to NAD+ was severely compromised. It is suspected that this impairment may be linked to the photoabsorption of biophotons in the blue wavelength range (492-455 nm). The photobiomodulation to Complex I was suspected to contribute greatly to the inefficiency of ATP synthase function since it resulted in a lower quantity of H+ ions to be available for use in the process of chemiosmosis. Other reactions of the ETC were not significantly impacted. Overall, these results provide evidence for a link between biophoton emission and biomodulation of the mitochondrial ATP synthesis process. However, there are many aspects of biological modulation by radiation-induced biophotons which will require further elucidation.
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Affiliation(s)
- Michelle Le
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Fiona E McNeill
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Colin B Seymour
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Andrej Rusin
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Kevin Diamond
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Andrew J Rainbow
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - James Murphy
- Institute of Technology Sligo, F91 YW50, Ireland
| | - Carmel E Mothersill
- McMaster University, 1280, Main Street West, Hamilton, Ontario, Canada L8S 4K1.
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Kaynezhad P, Tachtsidis I, Jeffery G. Optical monitoring of retinal respiration in real time: 670 nm light increases the redox state of mitochondria. Exp Eye Res 2016; 152:88-93. [PMID: 27664904 PMCID: PMC5105829 DOI: 10.1016/j.exer.2016.09.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/18/2016] [Accepted: 09/20/2016] [Indexed: 02/03/2023]
Abstract
Mitochondria play a key role in ageing and disease. Their membrane potentials and ATP production decline with age and this is associated with progressive inflammation, cell loss and death. Here we use broadband Near-Infrared Spectroscopy (NIRS) to non-invasively measure in-vivo changes in aged retinal mitochondrial respiration following exposure to 670 nm, which improves mitochondrial performance and reduces inflammation. Low power NIR light was shone into the eye via a fibre optic and the reflection monitored to measure signature changes in the oxidation of cytochrome c oxidase (COX) in complex IV of the electron transport chain. Changes in retinal haemodynamics and oxygenation were also recorded simultaneously with COX by measuring changes in oxygenated and deoxygenated haemoglobin (Δ[HbO2] and Δ[HHb]). Retinae of aged rats exposed to 670 nm for 5 mins showed consistent progressive increases in oxidation of COX 5 mins post exposure. This remained significantly greater than baseline for up to 2 h. This was not seen when retinae were exposed to 420 nm light of the same power or when no light was applied. 670 nm exposure significantly increased total haemoglobin concentration (Δ[HbT] = Δ[HbO2] +Δ[HHb]) but not haemoglobin difference (Δ[HbDiff] = Δ[HbO2] -Δ[HHb]). There were no changes in blood metrics in association with 420 nm light or when no light exposure was given. Hence, brief 670 nm exposure that is associated with reduced inflammation has a significant positive impact on the redox state of COX in aged retinae. The relative redox state of retinal COX may provide a valuable biomarker in ageing and macular degeneration where declining mitochondrial function is implicated. We measure real time retinal reflections in vivo in rats. We isolate signals from oxy/deoxy haemoglobin and those from relative COX redox. 670 nm increases COX redox and total haemoglobin improving mitochondrial function. These measurements monitor retinal respiration and may be a biomarker for disease.
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Affiliation(s)
- Pardis Kaynezhad
- Dept of Medical Physics and Biomedical Engineering, University College London, UK
| | - Ilias Tachtsidis
- Dept of Medical Physics and Biomedical Engineering, University College London, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, UK.
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Osborne NN, Núñez-Álvarez C, del Olmo-Aguado S. The effect of visual blue light on mitochondrial function associated with retinal ganglions cells. Exp Eye Res 2014; 128:8-14. [DOI: 10.1016/j.exer.2014.08.012] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/18/2014] [Accepted: 08/20/2014] [Indexed: 11/16/2022]
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Niwano Y, Kanno T, Iwasawa A, Ayaki M, Tsubota K. Blue light injures corneal epithelial cells in the mitotic phase in vitro. Br J Ophthalmol 2014; 98:990-2. [PMID: 24682182 DOI: 10.1136/bjophthalmol-2014-305205] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Yoshimi Niwano
- Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Taro Kanno
- Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Atsuo Iwasawa
- Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Masahiko Ayaki
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
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12
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Osborne NN. WITHDRAWN: Reprint of: Mitochondria: Their role in ganglion cell death and survival in primary open angle glaucoma. Exp Eye Res 2011:S0014-4835(11)00225-9. [PMID: 21819980 DOI: 10.1016/j.exer.2011.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 03/08/2010] [Indexed: 11/20/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.exer.2010.03.008. The duplicate article has therefore been withdrawn.
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Affiliation(s)
- Neville N Osborne
- Nuffield Laboratory of Ophthalmology, University of Oxford, UK; Instituto Oftalmologico, Fundación de Investigación Optalmologica, Fernandez-Vega, Oviedo, Spain
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van Norren D, Gorgels TGMF. The action spectrum of photochemical damage to the retina: a review of monochromatic threshold data. Photochem Photobiol 2011; 87:747-53. [PMID: 21410704 DOI: 10.1111/j.1751-1097.2011.00921.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photochemical damage to the retina occurs for prolonged exposures of intense light. Two action spectra exist for this phenomenon. In rat an action spectrum matching the absorption spectrum of rhodopsin was found. In macaque, the susceptibility for photochemical damage decreased continuously from the UV to long visible wavelengths. Later, such a spectrum was also found in rat. In search for critical parameters that determine the shape of the spectrum we gathered all available data on the damage threshold dose for monochromatic radiation and noted the experimental conditions. The rhodopsin action spectrum was found in two sources; the other 16 sources adhered to the short wavelength spectrum. Comparing the conditions we conclude that the critical parameters for the generation of either action spectrum remain elusive. Experiments are suggested to resolve this issue and fill a few gaps in our knowledge.
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Affiliation(s)
- Dirk van Norren
- University Medical Center Utrecht, and TNO, Soesterberg, The Netherlands.
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Light effects on mitochondrial photosensitizers in relation to retinal degeneration. Neurochem Res 2010; 35:2027-34. [PMID: 20927586 DOI: 10.1007/s11064-010-0273-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2010] [Indexed: 12/20/2022]
Abstract
The retina captures and converts light between 400-760 nm into electrical signals that are sent to the brain by way of the optic nerve and in the process helps to translate these electrical signals into what is known as vision. The same light that allows vision to occur is nevertheless also potentially toxic to retinal cells in certain situations. The shorter wavelengths of light are known to interact with chromophores in photoreceptors and pigment epithelial cells to cause oxidative stress and severe damage. Indeed it is generally accepted that short wavelength light effects is one cause for loss of photoreceptor function in age-related macular degeneration. Recent studies have demonstrated that light may be a contributing factor for the death of retinal ganglion cells in certain situations. Light as impinging on the retina, especially the short wavelength form, affect mitochondrial chromophores and can result in neurone death. Importantly ganglion cell axons within the eye are laden with mitochondria and unlike the outer retina are not protected from short wavelength light by macular pigments. It has therefore been proposed that when ganglion cell function is already compromised, as in glaucoma, then light impinging on their mitochondria might be a contributor to their eventual demise.
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Jarrett SG, Lewin AS, Boulton ME. The importance of mitochondria in age-related and inherited eye disorders. Ophthalmic Res 2010; 44:179-90. [PMID: 20829642 PMCID: PMC2952187 DOI: 10.1159/000316480] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mitochondria are critical for ocular function as they represent the major source of a cell's supply of energy and play an important role in cell differentiation and survival. Mitochondrial dysfunction can occur as a result of inherited mitochondrial mutations (e.g. Leber's hereditary optic neuropathy and chronic progressive external ophthalmoplegia) or stochastic oxidative damage which leads to cumulative mitochondrial damage and is an important factor in age-related disorders (e.g. age-related macular degeneration, cataract and diabetic retinopathy). Mitochondrial DNA (mtDNA) instability is an important factor in mitochondrial impairment culminating in age-related changes and pathology, and in all regions of the eye mtDNA damage is increased as a consequence of aging and age-related disease. It is now apparent that the mitochondrial genome is a weak link in the defenses of ocular cells since it is susceptible to oxidative damage and it lacks some of the systems that protect the nuclear genome, such as nucleotide excision repair. Accumulation of mitochondrial mutations leads to cellular dysfunction and increased susceptibility to adverse events which contribute to the pathogenesis of numerous sporadic and chronic disorders in the eye.
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Affiliation(s)
- Stuart G. Jarrett
- Department of Molecular and Biomedical Pharmacology, College of Medicine, University of Kentucky, Lexington, Ky., USA
| | - Alfred S. Lewin
- Department of Molecular Genetics, University of Florida, Gainesville, Fla., USA
| | - Michael E. Boulton
- Department of Anatomy and Cell Biology, College of Medicine, University of Florida, Gainesville, Fla., USA
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Mitochondria: Their role in ganglion cell death and survival in primary open angle glaucoma. Exp Eye Res 2010; 90:750-7. [DOI: 10.1016/j.exer.2010.03.008] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 12/12/2022]
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17
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Blay J, Price RB. Cellular inhibition produced by dental curing lights is a heating artifact. J Biomed Mater Res B Appl Biomater 2010; 93:367-74. [DOI: 10.1002/jbm.b.31591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Osborne NN, Li GY, Ji D, Mortiboys HJ, Jackson S. Light affects mitochondria to cause apoptosis to cultured cells: possible relevance to ganglion cell death in certain optic neuropathies. J Neurochem 2008; 105:2013-28. [DOI: 10.1111/j.1471-4159.2008.05320.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Osborne NN. Pathogenesis of ganglion “cell death” in glaucoma and neuroprotection: focus on ganglion cell axonal mitochondria. PROGRESS IN BRAIN RESEARCH 2008; 173:339-52. [DOI: 10.1016/s0079-6123(08)01124-2] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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21
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Zhang B, Rusciano D, Osborne NN. Orally administered epigallocatechin gallate attenuates retinal neuronal death in vivo and light-induced apoptosis in vitro. Brain Res 2007; 1198:141-52. [PMID: 18255049 DOI: 10.1016/j.brainres.2007.12.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 11/30/2007] [Accepted: 12/06/2007] [Indexed: 12/27/2022]
Abstract
The aim of this study was to provide support for epigallocatechin gallate (EGCG), a component of green tea, to be considered in the context for neuroprotection in glaucoma, where administration by an oral route is required for adequate penetration into the retina. Ischemia was delivered to one eye of a number of rats by raising the intraocular pressure. EGCG was present in the drinking water of half of the animals 3 days before ischemia and also during the next 5 days of reperfusion. The electroretinograms (ERGs) of both eyes from all rats were recorded before ischemia and 5 days following ischemia. Seven days after ischemia retinas from both eyes of all rats were either analysed for the localisation of various antigens or extracts prepared for analysis for the level of specific proteins and mRNAs. Ischemia/reperfusion to the retina affected a number of parameters. These included the localisation of Thy-1 and choline acetyltransferase, the a- and b-wave amplitudes of the ERG, the content of certain retinal and optic nerve proteins and various mRNAs. Significantly, EGCG statistically blunted many of the effects induced by ischemia/reperfusion which included the activation of caspases. These studies demonstrate conclusively that orally administered EGCG attenuates injury to the retina caused by ischemia/reperfusion where caspases were activated. Studies were also conducted on a cell line (RGC-5 cells) where it was shown that white light (1000 lx, 48 h)-induced apoptosis is caspase-independent and can be blunted by EGCG. The present studies support the view for the use of EGCG in the treatment of glaucoma based on the premise that any potential neuroprotective agent must be administered orally, have a safe profile and poses a broad spectrum of properties that allows various risk factors (that include ischemia and light) to be attenuated.
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Affiliation(s)
- Bo Zhang
- Nuffield Laboratory of Ophthalmology, Walton Street, Oxford OX2 6AW, UK
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22
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Ji D, Li GY, Osborne NN. Nicotinamide attenuates retinal ischemia and light insults to neurones. Neurochem Int 2007; 52:786-98. [PMID: 17976861 DOI: 10.1016/j.neuint.2007.09.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 09/10/2007] [Accepted: 09/13/2007] [Indexed: 01/26/2023]
Abstract
The aim of the present studies was to determine whether nicotinamide is effective in blunting the negative influence of ischemia/reperfusion to the rat retina in situ and of light to transformed retinal ganglion cells (RGC-5 cells) in culture. Ischemia was delivered to the retina of one eye of rats by raising the intraocular pressure. Nicotinamide was administered intraperitoneally just before ischemia and into the vitreous immediately after the insult. Electroretinograms (ERGs) of both eyes were recorded before and 5 days after ischemia. Seven days after ischemia, retinas were analysed for the localization of various antigens. Retinal and optic nerve extracts were also prepared for analysis of specific proteins and mRNAs. Also, RGC-5 cells in culture were given a light insult (1000 lux, 48 and 96 h) and evidence for reduced viability and apoptosis determined by a variety of procedures. Nicotinamide was added to some cultures to see whether it reversed the negative effect of light. Ischemia/reperfusion to the retina affected the localization of Thy-1, neuronal nitric oxide synthase (NOS) and choline acetyltransferase (ChAT), the a- and b-wave amplitudes of the ERG, the content of various retinal and optic nerve proteins and mRNAs. Significantly, nicotinamide statistically blunted many of the effects induced by ischemia/reperfusion which included the activation of poly-ADP-ribose polymerase (PARP). Light-induced apoptosis of RGC-5 cells in culture was attenuated by nicotinamide and the PARP inhibitor NU1025. The presented data show that nicotinamide attenuates injury to the retina and RGC-5 cells in culture caused by ischemia/reperfusion and by light, respectively. Evidence is provided to suggest that nicotinamide acts as a PARP inhibitor and possibly an antioxidant.
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Affiliation(s)
- Dan Ji
- Nuffield Laboratory of Ophthalmology, University of Oxford, Walton Street, Oxford OX2 6AW, UK
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Lascaratos G, Ji D, Wood JPM, Osborne NN. Visible light affects mitochondrial function and induces neuronal death in retinal cell cultures. Vision Res 2007; 47:1191-201. [PMID: 17306853 DOI: 10.1016/j.visres.2006.12.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 12/01/2006] [Accepted: 12/08/2006] [Indexed: 12/24/2022]
Abstract
The aim of this study was to provide "proof of principle" for the hypothesis that light would have a detrimental influence on ganglion cells in certain situations, like in glaucoma, by directly impinging on the many mitochondria in their axons within the globe. In this study primary rat retinal cultures and freshly isolated liver mitochondria were exposed to light (400-760 nm; 500-4000 lux) as entering the eye. For culture assessment, 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 4-[3-(-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetzolio]-1,3-benzene disulfonate (WST-1) reduction assays were used to assess cell and mitochondrial viability, respectively. Furthermore, cultures were stained for reactive oxygen species (ROS), DNA breakdown, numbers of GABA-immunoreactive (IR) cells and caspase-3 content to provide information concerning the effect of light on neuronal survival. Uptake of (3)H-GABA by autoradiography was also used, to assess the effects of light on the energy status of neurons. Light, in an intensity-dependent and trolox-inhibitable manner, reduced cell viability, affected mitochondrial function, increased the number of TUNEL-positive cells, decreased the numbers of GABA-IR neurons and enhanced labelling for ROS. These effects were all exacerbated by the absence of serum. There was also an increased caspase-3 protein content and a reduction of (3)H-GABA uptake in light- compared with dark-treated cultures. These findings support the hypothesis that light can affect mitochondria which could lead to neuronal apoptosis if the energetic status of these neurons is already compromised.
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Affiliation(s)
- Gerassimos Lascaratos
- Nuffield Laboratory of Ophthalmology, University of Oxford, Walton Street, Oxford OX2 6AW, UK
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24
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Godley BF, Shamsi FA, Liang FQ, Jarrett SG, Davies S, Boulton M. Blue Light Induces Mitochondrial DNA Damage and Free Radical Production in Epithelial Cells. J Biol Chem 2005; 280:21061-6. [PMID: 15797866 DOI: 10.1074/jbc.m502194200] [Citation(s) in RCA: 283] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure of biological chromophores to ultraviolet radiation can lead to photochemical damage. However, the role of visible light, particularly in the blue region of the spectrum, has been largely ignored. To test the hypothesis that blue light is toxic to non-pigmented epithelial cells, confluent cultures of human primary retinal epithelial cells were exposed to visible light (390-550 nm at 2.8 milliwatts/cm2) for up to 6 h. A small loss of mitochondrial respiratory activity was observed at 6 h compared with dark-maintained cells, and this loss became greater with increasing time. To investigate the mechanism of cell loss, the damage to mitochondrial and nuclear genes was assessed using the quantitative PCR. Light exposure significantly damaged mitochondrial DNA at 3 h (0.7 lesion/10 kb DNA) compared with dark-maintained controls. However, by 6 h of light exposure, the number of lesions was decreased in the surviving cells, indicating DNA repair. Isolated mitochondria exposed to light generated singlet oxygen, superoxide anion, and the hydroxyl radical. Antioxidants confirmed the superoxide anion to be the primary species responsible for the mitochondrial DNA lesions. The effect of lipofuscin, a photoinducible intracellular generator of reactive oxygen intermediates, was investigated for comparison. Exposure of lipofuscin-containing cells to visible light caused an increase in both mitochondrial and nuclear DNA lesions compared with non-pigmented cells. We conclude that visible light can cause cell dysfunction through the action of reactive oxygen species on DNA and that this may contribute to cellular aging, age-related pathologies, and tumorigenesis.
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Agarwal N, Martin E, Krishnamoorthy RR, Landers R, Wen R, Krueger S, Kapin MA, Collier RJ. Levobetaxolol-induced Up-regulation of retinal bFGF and CNTF mRNAs and preservation of retinal function against a photic-induced retinopathy. Exp Eye Res 2002; 74:445-53. [PMID: 12076088 DOI: 10.1006/exer.2001.1145] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Betaxolol (racemic), a beta-adrenoceptor antagonist that is used to lower intraocular pressure in the treatment of glaucoma, has been shown to protect inner retina cells from various insults. To determine if such protection could be afforded to retinal photoreceptors and retinal pigment epithelial cells (RPE), levobetaxolol (S-betaxolol) was evaluated in a photic-induced retinopathy model. Rats were dosed (IP) with vehicle or levobetaxolol (10 and 20 mg kg(-1)) 48, 24 and 0 hr prior to exposure for 6 hr to fluorescent blue light. The electroretinogram (ERG) and retinal morphology were assessed after a 3 week recovery period. Evaluation of the ERG demonstrated significant protection of retinal function in levobetaxolol (20 mg kg(-1))-dosed rats compared to vehicle-dosed rats. Similarly, the RPE and outer nuclear layer were significantly thicker in levobetaxolol (20 mg kg(-1))-dosed rats compared to vehicle-dosed rats. To elucidate potential mechanism(s) of the neuroprotective activity of levobetaxolol, bFGF and CNTF mRNA levels in normal rat retinas were evaluated 12 hr after a single i.p. injection. Northern blot analysis of levobetaxolol treated retinas demonstrated a 10-fold up-regulation of bFGF and a two-fold up-regulation of CNTF mRNA levels, trophic factors that have been shown to inhibit retinal degeneration in a number of species. These studies suggest that levobetaxolol can be used as a novel neuroprotective agent to ameliorate retinopathy.
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Affiliation(s)
- Neeraj Agarwal
- Department of Pathology and Anatomy, Division of Cell Biology and Genetics, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA
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Boulton M, Rózanowska M, Rózanowski B. Retinal photodamage. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 64:144-61. [PMID: 11744401 DOI: 10.1016/s1011-1344(01)00227-5] [Citation(s) in RCA: 234] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The retina represents a paradox, in that, while light and oxygen are essential for vision, these conditions also favour the formation of reactive oxygen species leading to photochemical damage to the retina. Such light damage seems to be multi-factorial and is dependent on the photoreactivity of a variety of chromophores (e.g., vitamin A metabolites, lipofuscin, melanin, flavins, porphyrins, carotenoids) endogenous to the retina. The aim of this article is to provide a detailed review of our current understanding of the photochemistry and photobiology of these chromophores and to consider how they may contribute to retinal ageing and pathology.
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Affiliation(s)
- M Boulton
- Department of Optometry and Vision Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB, UK.
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Hanna N, Peri KG, Abran D, Hardy P, Doke A, Lachapelle P, Roy MS, Orquin J, Varma DR, Chemtob S. Light induces peroxidation in retina by activating prostaglandin G/H synthase. Free Radic Biol Med 1997; 23:885-97. [PMID: 9378368 DOI: 10.1016/s0891-5849(97)00083-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Prostaglandin G/H synthase (PGHS) has been shown to generate peroxides to a significant extent in the retina and absorbs light at the lower end of the visible spectrum. We postulated that PGHS could be an important initial source of peroxidation in the retina exposed to light, which would in turn alter retinal function. Exposure of pig eyes (in vivo) to light (350 fc/3770 lx) caused after 3 h a 50% increase and by 5 h a 30% decrease in a- and b-wave amplitudes of the electroretinogram (ERG) which were comparable at 380-650 nm and 380-440 nm but were not observed at wavelengths > 450 nm. These effects of light were prevented by free radical scavengers (dimethylthiourea and high-dose allopurinol) and PGHS inhibitors (naproxen and diclofenac), but stable analogs of prostaglandins did not affect the ERG. Both increases and subsequent decreases in ERG wave amplitudes following light exposure in vivo were associated with increases in retinal prostaglandin and malondialdehyde (peroxidation product) levels, which were inhibited by the nonselective PGHS blockers, naproxen and diclofenac. Similar observations were made in vitro on isolated porcine eyecups as well as on retinal membranes exposed to light (250 fc/ 2700 lx) 380-650 nm and 380-440 nm but not at > 500 nm. Both PGHS-1 and PGHS-2 contributed equivalently to light-induced prostaglandin synthesis, as shown after selective PGHS-2 blockers, but mRNA expression of PGHS-1 and 2 was not affected by light. Finally, light stimulated activities of pure PGHS-1 and PGHS-2 isozymes, and these were also shown to produce superoxide radical (detected with fluorogenic spin trap, proxyl fluorescamine). Taken together, data suggest that PGHS- (1 and 2) is activated by short wavelength visible light, and in the retina is an important source of reactive oxygen species which in turn alter retinal electrophysiological function. PGHS thus seems a likely chromophore in setting forth photic-induced retinal injury. Findings provide an explanation for increased sensitivity of the retina to visible light predominantly at the far blue range of its spectrum.
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Affiliation(s)
- N Hanna
- Department of Pediatrics, Research Center of Hôpital Stc-Justine, University of Montreal, Canada
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Löfgren S, Söderberg PG. Rat lens glycolysis after in vivo exposure to narrow band UV or blue light radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1995; 30:145-51. [PMID: 8558367 DOI: 10.1016/1011-1344(95)07183-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
UV radiation and short wavelength visible light are known to damage various tissues in the eye. This paper investigates the effect on rat lens glycolysis after in vivo exposure with 90 kJ m-2 narrow band UV radiation (UVB, 300 nm) and 90 kJ m-2 blue light (435 nm) radiation. After exposure, all lenses were incubated in Medium 199. Samples of culture medium were withdrawn after 2, 4, 6 h and 5, 10, 20 h in two UVB studies and after 5, 10 and 20 h in a blue light study. Lactate is the major end product of lens glycolysis. Lactate was determined with a modified enzymatic-photometric method. Intralenticular lactate was determined in one UVB experiment. In the UVB experiments we found a lower lactate production in the exposed lenses 2-6 h after exposure. There was an accumulation of lactate inside UVB-exposed lenses after 6 h incubation compared with their contralateral lenses. No significant effect on lactate production was observed in the blue light experiment. CONCLUSIONS. UVB induced a reversible inhibition of glycolysis. UVB also induced an accumulation of lactate inside the lens. Blue light tended to increase glycolysis.
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Affiliation(s)
- S Löfgren
- Research Department, St. Erik Eye Hospital, Stockholm, Sweden
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Chen E, Pallon J, Forslind B. Distribution of calcium and sulphur in the blue-light-exposed rat retina. Graefes Arch Clin Exp Ophthalmol 1995; 233:163-7. [PMID: 7758984 DOI: 10.1007/bf00166609] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Blue-light exposure inhibits cytochrome oxidase and may therefore inhibit retinal metabolism. The reduced metabolism decreases the extrusion of calcium from the photoreceptor cell. Overload of calcium is proposed as one of the factors that lead to photoreceptor degeneration after light exposure. The light-induced photoreceptor degeneration can be ameliorated by calcium overload blocker. In the present study the calcium concentration was measured in the inner and outer segment layer of the rat retina. METHODS Six eyes were exposed to blue (404 nm) light at a retinal dose of 380 kJ/m2. Five eyes served as the control group. The calcium and sulphur distributions were measured with a nuclear microprobe in the freeze-dried rat retina. The proton beam size was 12 x 12 microns and the energy of the protons was 2.55 MeV. The calcium concentration was calculated using sulphur as a reference. RESULTS The level of calcium per milligram sulphur was 21 micrograms (range 17-23 micrograms) in the inner segment of the control retina. It increased to 62 micrograms/mg sulphur (range 57-67 micrograms) and 61 micrograms/mg sulphur (range 58-66 micrograms) 1 h and 12 h after blue-light exposure, respectively. CONCLUSION The findings of the present study support the idea that accumulation of calcium in the inner segment layer is one of the factors that cause photoreceptor degeneration.
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Affiliation(s)
- E Chen
- Research Department, St. Erik's Eye Hospital, Stockholm, Sweden
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30
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Anderson RE, Kretzer FL, Rapp LM. Free radicals and ocular disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 366:73-86. [PMID: 7771292 DOI: 10.1007/978-1-4615-1833-4_6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ames, Shigenaga, and Hagen recently published a thorough review of the relationship between oxidants, antioxidants, and degenerative diseases of ageing. They point out that only 9% of Americans daily consume the two fruits and three vegetables recommended by the National Cancer Institute and the National Research Council/National Academy of Science. In addition to antioxidants, these foodstuffs contain many essential micronutrients. To date, specific recommendations for antioxidant supplementation have not been made by any governmental agency or professional association. A number of clinical, basic, and epidemiological studies have implicated free radical induced lipid peroxidation in various ocular disorders. It would seem prudent that those persons at greatest risk for these disorders take some precautions, which could include sunglasses that filter ultraviolet light; hats that shield the eyes from direct sunlight; and the ingestion of fruits, vegetables, and antioxidants.
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Affiliation(s)
- R E Anderson
- Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030, USA
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31
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Chen E. Inhibition of cytochrome oxidase and blue-light damage in rat retina. Graefes Arch Clin Exp Ophthalmol 1993; 231:416-23. [PMID: 8406068 DOI: 10.1007/bf00919652] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The activity of cytochrome oxidase, outer nuclear layer thickness, and edema were quantitatively evaluated in the blue-light exposed rat retina. Dark-adapted or cyclic-light reared rats were exposed to blue light with a retinal dose of 380 kJ/m2. Immediately, 1, 2, and 3 day(s) after exposure, the retinas of six rats from each adaptation group were examined. There was no difference between the dark-adapted and cyclic-light reared rats. Immediately after light exposure, cytochrome oxidase activity decreased. The activity in the inner segments remained low at day 1, while severe edema was observed in the inner and outer segments. The outer nuclear layer thickness decreased 1-3 days after exposure. The blue-light exposure inhibited cytochrome oxidase activity and caused retinal injury. Similarity of the injury process in the dark-adapted and cyclic-light reared retinas suggests that rhodopsin was not involved. The inhibition of cytochrome oxidase could be a cause of retinal damage.
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Affiliation(s)
- E Chen
- St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden
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