title: Compared antioxidant activity among corticosteroids on cultured retinal pigment epithelial cells.
abstract: OBJECTIVE
  The aim of this study is to determine if dexamethasone, prednisolone and triamcinolone acetonide (TA), three anti-inflammatory drugs commonly used for ocular treatments, could affect the oxidative status of cultured human cells of the retinal pigment epithelium (RPE) and protect them against oxidative injury.
  
  
  METHODS
  ARPE-19 cells were used as an in vitro model of RPE. Glutathione (GSH) levels were assessed to evaluate the effects of dexamethasone, prednisolone and triamcinolone on cellular antioxidant status. Oxidative stress was induced in ARPE-19 cells by treatment with the oxidizing agent menadione, and the effects of dexamethasone, prednisolone and triamcinolone were evaluated. Release of lactate dehydrogenase (LDH) in the culture medium was used to measure cytotoxicity.
  
  
  RESULTS
  Incubation with triamcinolone or prednisolone was not able to revert menadione-induced cytotoxicity and GSH depletion; furthermore, it significantly decreased GSH levels in ARPE-19 cells (nmol of GSH/mg cellular protein: 99.7 ± 0.1 in untreated controls vs. 52.6 ± 5.2 with triamcinolone vs. 77.6 ± 5.2 with prednisolone; p < 0.001). Treatment with dexamethasone protected ARPE-19 cells from cytotoxicity and oxidative damage: lactate dehydrogenase release and GSH depletion were significantly decreased after incubation with this compound (LDHout/LDHtot: 0.221 ± 0.038 with menadione vs. 0.041 ± 0.007 with menadione + dexamethasone; p < 0.001; nmol of GSH/mg cellular protein: 5.7 ± 4.2 with menadione vs. 53.2 ± 6.1 with menadione + dexamethasone, respectively; p < 0.001) and did not induce GSH depletion (nmol of GSH/mg cellular protein: 99.7 ± 0.1 vs. 86.5 ± 8.1 nmol/min/mg prot with dexamethasone; p > 0.05).
  
  
  CONCLUSIONS
  Dexamethasone, besides suppressing intraocular inflammation, may protect human RPE cells from oxidative stress and decrease the oxidation rate of GSH. Triamcinolone and prednisolone, inducing GSH depletion, may contribute to reduce antioxidant capacity of ARPE-19 cells.
authors.affiliation: Division of Ophthalmology, Department of Surgical Sciences, University of Turin, San Luigi Gonzaga Hospital, Regione Gonzole 10, 10043, Orbassano, TO, Italy.
authors.forename: Nuzzi
authors.initials: N
authors.lastname: Raffaele
authors.affiliation: Division of Ophthalmology, Department of Surgical Sciences, University of Turin, San Luigi Gonzaga Hospital, Regione Gonzole 10, 10043, Orbassano, TO, Italy. amarchese@hotmail.it.
authors.forename: Alessandro
authors.identifier: http://orcid.org/0000-0001-7716-7261
authors.initials: A
authors.lastname: Marchese
authors.affiliation: Department of Oncology, University of Turin, Turin, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Ghigo
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002470:Cell Survival; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D006836:Hydro-Lyases / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D011239:Prednisolone / Q000494:pharmacology; D012164:Retinal Diseases / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D014222:Triamcinolone Acetonide / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D005938:Glucocorticoids; D003907:Dexamethasone; D011239:Prednisolone; D006836:Hydro-Lyases; C045581:lactate dehydratase; D014222:Triamcinolone Acetonide
keywords: ARPE-19; Dexamethasone; Oxidative stress; Prednisolone; Triamcinolone