title: Dexamethasone reduces mitomycin C-related inflammatory cytokine expression without inducing further cell death in corneal fibroblasts.
abstract: The purpose of this study was to investigate the effect of dexamethasone (DEX) on mitomycin C (MMC)-induced inflammatory cytokine expression in corneal fibroblasts. Primary human corneal fibroblasts were treated with MMC, dexamethasone, or in combination. Morphological changes and cell growth were documented using phase-contrast microscopy and PicoGreen assay, respectively. Cell apoptosis was evaluated by annexin V/propidium iodide staining, whereas viability was tested by the live/dead assay and analyzed by flow cytometry. The relative expression of interleukin-8 and monocyte chemoattractant protein-1 was investigated with quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Mitogen-activated protein kinase activation and mitogen-activated protein kinase phosphatase-1 expression were documented by Western blot analysis. We found that MMC induced corneal fibroblast elongation, apoptosis, and retarded cell growth, whereas DEX did not significantly alter cell morphology or viability. The combination of DEX and MMC did not induce additional apoptosis and cell death. DEX dose dependently down-regulated basal and MMC-induced interleukin-8 and monocyte chemoattractant protein-1 mRNA expression and protein secretion. DEX attenuated MMC-induced p38 and Jun N-terminal kinases activation and up-regulated expression. These suggested that DEX may inhibit MMC-induced interleukin-8 and monocyte chemoattractant protein-1 by up-regulating MKP-1 expression, which subsequently deactivated p38 and Jun N-terminal kinases activation. Combined MMC and DEX treatment may facilitate corneal wound healing.
authors.affiliation: Department of Ophthalmology, Far Eastern Memorial Hospital, Ban-Chiao, Taipei, Taiwan. swchang2007@ntu.edu.tw
authors.forename: Shu-Wen
authors.initials: SW
authors.lastname: Chang
authors.forename: San-Fang
authors.initials: SF
authors.lastname: Chou
authors.forename: Shuen-Yuen
authors.initials: SY
authors.lastname: Yu
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D016923:Cell Death / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism*; D003315:Cornea / Q000166:cytology* / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D054638:Dual Specificity Phosphatase 1 / Q000378:metabolism; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D008858:Microscopy, Phase-Contrast; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016685:Mitomycin / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D015854:Up-Regulation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D005938:Glucocorticoids; D016209:Interleukin-8; D016685:Mitomycin; D003907:Dexamethasone; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D054638:Dual Specificity Phosphatase 1