title: Cytostatic and cytotoxic effects of 5-fluorouracil on human corneal epithelial cells and keratocytes.
abstract: OBJECTIVE
  To investigate the effects of various 5-fluorouracil (5-FU) concentrations, exposure times, and application techniques on in vitro-cultured human corneal cells.
  
  
  METHODS
  Human corneal epithelial cell (HCEC) and human corneal keratocyte (HCK) cultures were exposed to different 5-FU concentrations (0.025%-1%) and incubation durations (5 minutes to 2 hours). The cytostatic effect was evaluated as the percentage of inhibition of migration relative to the control. The evaluation of cytotoxic effect included both phase contrast microscopic observations and viability measures performed using an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)] colorimetric assay. The results are expressed as ratio of optical density (OD) reduction 24 hours after exposure.
  
  
  RESULTS
  The cytostatic effect was time and dose dependent. The 50% inhibiting dose was 0.55% after 1 hour of incubation for HCECs and was 0.5% after 2 hours of incubation for HCKs. A 100% inhibitory effect was never observed at any concentration or incubation duration. No cytotoxic changes were observed using an 5-FU concentration of <1%; 1% 5-FU showed time-dependent cytotoxic changes in HCEC cultures only. MTT analysis showed no OD reduction at 5-FU concentrations of <1%, whereas 1% 5-FU showed OD reduction <50% at any tested exposure time. HCECs showed higher reduction in OD than HCKs.
  
  
  CONCLUSIONS
  5-FU formulations topically used in clinical practice showed limited toxicity in normal cultured corneal epithelial cells and keratocytes.
authors.affiliation: Department of Ophthalmology, University of Padova, Padova, Italy. edoardo.midena@unipd.it
authors.forename: Edoardo
authors.initials: E
authors.lastname: Midena
authors.forename: Daniela
authors.initials: D
authors.lastname: Lazzarini
authors.forename: Anton Giulio
authors.initials: AG
authors.lastname: Catania
authors.forename: Erika
authors.initials: E
authors.lastname: Moretto
authors.forename: Iva
authors.initials: I
authors.lastname: Fregona
authors.forename: Raffaele
authors.initials: R
authors.lastname: Parrozzani
mesh_terms: D000963:Antimetabolites / Q000633:toxicity*; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D002478:Cells, Cultured; D003124:Colorimetry; D060527:Corneal Keratocytes / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D019573:Epithelium, Corneal / Q000187:drug effects*; D005472:Fluorouracil / Q000633:toxicity*; D006801:Humans; D008858:Microscopy, Phase-Contrast; D013997:Time Factors; D014019:Tissue Donors
chemical_list: D000963:Antimetabolites; D005472:Fluorouracil