title: Diclofenac protects cultured human corneal epithelial cells against hyperosmolarity and ameliorates corneal surface damage in a rat model of dry eye.
abstract: OBJECTIVE
  Dry eye syndrome (DES) is characterized by an increase in tear osmolarity and induction of the expression and nuclear localization of an osmoprotective transcription factor (nuclear factor of activated T-cells 5 [NFAT5]) that plays an important role in providing protection against hyperosmotic tears. In this study, we screened medicines already in clinical use with a view of finding compounds that protect cultured human corneal epithelial cells against hyperosmolarity-induced cell damage.
  
  
  METHODS
  Viable cell number was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and cellular NFAT5 level was measured by immunoblotting. The rat model for DES was developed by removal of the lacrimal glands, with an assessment of corneal surface damage based on levels of fluorescein staining and epithelial apoptosis.
  
  
  RESULTS
  Some nonsteroidal anti-inflammatory drugs (NSAIDs), including diclofenac sodium (diclofenac), were identified during the screening procedure. These NSAIDs were able to suppress hyperosmolarity-induced apoptosis and cell growth arrest. In contrast, other NSAIDs, including bromfenac sodium (bromfenac), did not exert such a protective action. Treatment of cells with diclofenac, but not bromfenac, stimulated both the nuclear localization and expression of NFAT5 under hyperosmotic conditions. In the rat model for DES, topical administration of diclofenac (but not bromfenac) to eyes reduced corneal surface damage without affecting the volume of tear fluid.
  
  
  CONCLUSIONS
  Diclofenac appears to protect cells against hyperosmolarity-induced cell damage and NFAT5 would play an important role in this protective action. The findings reported here may also indicate that the topical administration of diclofenac to eyes may be therapeutically beneficial for DES patients.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Keio University, Tokyo, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Sawazaki
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Ishihara
authors.forename: Shinya
authors.initials: S
authors.lastname: Usui
authors.forename: Erika
authors.initials: E
authors.lastname: Hayashi
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tahara
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hoshino
authors.forename: Akihiro
authors.initials: A
authors.lastname: Higuchi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nakamura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsubota
authors.forename: Tohru
authors.initials: T
authors.lastname: Mizushima
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D002478:Cells, Cultured; D004008:Diclofenac / Q000627:therapeutic use*; D004195:Disease Models, Animal; D015352:Dry Eye Syndromes / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D009997:Osmotic Pressure / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C492199:Nfat5 protein, rat; D014157:Transcription Factors; D004008:Diclofenac
keywords: diclofenac; dry eye syndromes; hyperosmolarity; nuclear factor of activated T-cells 5