title: Effect of brief exposure to mitomycin C on cultured human nasal mucosa fibroblasts.
abstract: OBJECTIVE
  To observe the effect of mitomycin C (MMC) on cultured human nasal mucosa fibroblasts.
  
  
  METHODS
  Cultured human nasal mucosa fibroblasts were exposed to MMC (0.1-0.4 mg/ml) for 1 to 5 minutes. The viability of the fibroblasts was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay; DNA fragmentation (apoptosis) by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL); apoptotic percentage by flow cytometry; and morphology by light microscopy.
  
  
  RESULTS
  A portion of the fibroblasts survived the mitomycin treatment and showed evidence of regrowth within 2 to 3 days. These cells reached confluence in 5 to 7 days. The inhibition rates by MTT assay of 0.4 mg/ml MMC for 5-minute exposures was 31.3%. Dose-response effect was noted with the lower concentrations and shorter exposure times where the inhibition rates were lower (but not significantly so). DNA fragmentation was observed in fibroblasts 24 hours after MMC exposure (0.4 mg/ml) for 5 minutes compared with normal control. The apoptotic rate of fibroblasts treated by 0.4 mg/ml MMC was significantly higher than the control (p < 0.05).
  
  
  CONCLUSIONS
  Short MMC exposure times have a variable cytotoxic effect and inhibit proliferation of cultured nasal mucosa fibroblasts. MMC also can induce apoptosis with a 5-minute exposure time. Therefore, it is possible that MMC has a complex effect in dacryocystorhinostomy.
authors.affiliation: Department of Ophthalmology, University of Washington, Schools of Medicine, and Harborview Medical Center, Seattle 98195-6485, USA.
authors.forename: D
authors.initials: D
authors.lastname: Hu
authors.forename: B S
authors.initials: BS
authors.lastname: Sires
authors.forename: D C
authors.initials: DC
authors.lastname: Tong
authors.forename: G A
authors.initials: GA
authors.lastname: Royack
authors.forename: D
authors.initials: D
authors.lastname: Oda
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured / Q000187:drug effects; D004396:Coloring Agents; D004247:DNA / Q000032:analysis; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D016685:Mitomycin / Q000494:pharmacology*; D009297:Nasal Mucosa / Q000166:cytology / Q000187:drug effects*; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000477:Alkylating Agents; D004396:Coloring Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D016685:Mitomycin; D004247:DNA; C022616:thiazolyl blue