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Effects of melatonin and its receptor antagonist on retinal pigment epithelial cells against hydrogen peroxide damage.
Mol Vis. 2012; 18:1640-8.MV

Abstract

PURPOSE

Recently, we reported finding that circulating melatonin levels in age-related macular degeneration patients were significantly lower than those in age-matched controls. The purpose of this study was to investigate the hypothesis that melatonin deficiency may play a role in the oxidative damage of the retinal pigment epithelium (RPE) by testing the protective effect of melatonin and its receptor antagonist on RPE cells exposed to H(2)O(2) damage.

METHODS

Cultured human RPE cells were subjected to oxidative stress induced by 0.5 mM H(2)O(2). Cell viability was measured using the microculture tetrazoline test (MTT) assay. Cells were pretreated with or without melatonin for 24 h. Luzindole (50 μM), a melatonin membrane-receptor antagonist, was added to the culture 1 h before melatonin to distinguish direct antioxidant effects from indirect receptor-dependent effects. All tests were performed in triplicate.

RESULTS

H(2)O(2) at 0.5 mM decreased cell viability to 20% of control levels. Melatonin showed dose-dependent protective effects on RPE cells against H(2)O(2). Cell viability of RPE cells pretreated with 10(-10), 10(-8), 10(-6), and 10(-4) M melatonin for 24 h was 130%, 160%, 187%, and 230% of cells treated with H(2)O(2) alone (all p<0.05). Using cells cultured without H(2)O(2) as the control, cell viability of cells treated with H(2)O(2) after pretreatment with 10(-10)-10(-4) M melatonin was still significantly lower than that of the controls, suggesting that melatonin significantly decreased but did not completely abolish the in vitro cytotoxic effects of H(2)O(2). Luzindole completely blocked melatonin's protective effects at low concentrations of melatonin (10(-10)-10(-8) M) but not at high concentrations (10(-6)-10(-4) M).

CONCLUSIONS

Melatonin has a partial protective effect on RPE cells against H(2)O(2) damage across a wide range of concentrations (10(-10)-10(-4) M). This protective effect occurs through the activation of melatonin membrane receptors at low concentrations (10(-10)-10(-8) M) and through both the direct antioxidant and indirect receptor activation effects at high concentrations (10(-6)-10(-4) M).

Authors+Show Affiliations

Department of Ophthalmology, New York Eye and Ear Infirmary, New York Medical College, New York, NY, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22773902

Citation

Rosen, Richard B., et al. "Effects of Melatonin and Its Receptor Antagonist On Retinal Pigment Epithelial Cells Against Hydrogen Peroxide Damage." Molecular Vision, vol. 18, 2012, pp. 1640-8.
Rosen RB, Hu DN, Chen M, et al. Effects of melatonin and its receptor antagonist on retinal pigment epithelial cells against hydrogen peroxide damage. Mol Vis. 2012;18:1640-8.
Rosen, R. B., Hu, D. N., Chen, M., McCormick, S. A., Walsh, J., & Roberts, J. E. (2012). Effects of melatonin and its receptor antagonist on retinal pigment epithelial cells against hydrogen peroxide damage. Molecular Vision, 18, 1640-8.
Rosen RB, et al. Effects of Melatonin and Its Receptor Antagonist On Retinal Pigment Epithelial Cells Against Hydrogen Peroxide Damage. Mol Vis. 2012;18:1640-8. PubMed PMID: 22773902.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of melatonin and its receptor antagonist on retinal pigment epithelial cells against hydrogen peroxide damage. AU - Rosen,Richard B, AU - Hu,Dan-Ning, AU - Chen,Min, AU - McCormick,Steven A, AU - Walsh,Joseph, AU - Roberts,Joan E, Y1 - 2012/06/20/ PY - 2011/06/29/received PY - 2012/06/16/accepted PY - 2012/7/10/entrez PY - 2012/7/10/pubmed PY - 2012/11/14/medline SP - 1640 EP - 8 JF - Molecular vision JO - Mol. Vis. VL - 18 N2 - PURPOSE: Recently, we reported finding that circulating melatonin levels in age-related macular degeneration patients were significantly lower than those in age-matched controls. The purpose of this study was to investigate the hypothesis that melatonin deficiency may play a role in the oxidative damage of the retinal pigment epithelium (RPE) by testing the protective effect of melatonin and its receptor antagonist on RPE cells exposed to H(2)O(2) damage. METHODS: Cultured human RPE cells were subjected to oxidative stress induced by 0.5 mM H(2)O(2). Cell viability was measured using the microculture tetrazoline test (MTT) assay. Cells were pretreated with or without melatonin for 24 h. Luzindole (50 μM), a melatonin membrane-receptor antagonist, was added to the culture 1 h before melatonin to distinguish direct antioxidant effects from indirect receptor-dependent effects. All tests were performed in triplicate. RESULTS: H(2)O(2) at 0.5 mM decreased cell viability to 20% of control levels. Melatonin showed dose-dependent protective effects on RPE cells against H(2)O(2). Cell viability of RPE cells pretreated with 10(-10), 10(-8), 10(-6), and 10(-4) M melatonin for 24 h was 130%, 160%, 187%, and 230% of cells treated with H(2)O(2) alone (all p<0.05). Using cells cultured without H(2)O(2) as the control, cell viability of cells treated with H(2)O(2) after pretreatment with 10(-10)-10(-4) M melatonin was still significantly lower than that of the controls, suggesting that melatonin significantly decreased but did not completely abolish the in vitro cytotoxic effects of H(2)O(2). Luzindole completely blocked melatonin's protective effects at low concentrations of melatonin (10(-10)-10(-8) M) but not at high concentrations (10(-6)-10(-4) M). CONCLUSIONS: Melatonin has a partial protective effect on RPE cells against H(2)O(2) damage across a wide range of concentrations (10(-10)-10(-4) M). This protective effect occurs through the activation of melatonin membrane receptors at low concentrations (10(-10)-10(-8) M) and through both the direct antioxidant and indirect receptor activation effects at high concentrations (10(-6)-10(-4) M). SN - 1090-0535 UR - https://www.unboundmedicine.com/medline/citation/22773902/Effects_of_melatonin_and_its_receptor_antagonist_on_retinal_pigment_epithelial_cells_against_hydrogen_peroxide_damage_ L2 - https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22773902/ DB - PRIME DP - Unbound Medicine ER -