title: Does mitomycin C cause toxicity in the cornea after photorefractive keratectomy? A comparative wound-healing study in a refractive surgery animal model.
abstract: OBJECTIVE
  In this study, we investigated the wound-healing process after photorefractive keratectomy with mitomycin C (MMC) in hen corneas. In addition, we evaluated the synergistic effect of ethanol and MMC.
  
  
  METHODS
  Forty-eight adult hens were divided into 3 groups: A: ethanol-assisted debridement plus MMC; B: mechanical debridement plus MMC; and C: mechanical debridement (MMC-untreated control). Photorefractive keratectomy was performed, and the animals were followed up for up to 60 days. Epithelial healing was measured with fluorescein. Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end-labeling assay and proliferation was measured by BrdU incorporation. Both myofibroblast differentiation and collagen deposition were evaluated by immunofluorescence and histology.
  
  
  RESULTS
  Epithelial wound closure was similar in all 3 groups (P > 0.05). Significant reduction in haze was observed in groups A and B compared with C (P < 0.01), but there was no difference between groups A and B (P > 0.05). Furthermore, there was no difference in the number of apoptotic cells between groups. Proliferation was delayed in both groups A and B compared with C (P < 0.01), but groups A and B did not differ significantly (P > 0.05). Myofibroblasts, cellular density, and collagen deposition were lower in both groups A and B compared with C (P < 0.01), but they were not significantly different from each other (P > 0.05).
  
  
  CONCLUSIONS
  Topical application of MMC in hen corneas reproduces the wound healing observed in humans by reducing haze, keratocyte proliferation, myofibroblast differentiation, and new collagen deposition. Synergistic cytotoxic effects of ethanol and MMC were not observed.
authors.affiliation: *Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC; †Department of Ophthalmology, "Instituto Universitario de Oftalmobiología Aplicada" (IOBA), University of Valladolid, Valladolid, Spain; ‡Animal Facilities, University of Valladolid, Valladolid, Spain; §Department of Cell Biology and Pharmacology, University of Valladolid, Valladolid, Spain; and ¶Instituto Oftalmológico Fernández-Vega, Fundación de Investigación en Oftalmología, University of Oviedo, Oviedo, Spain.
authors.forename: Tomas
authors.initials: T
authors.lastname: Blanco-Mezquita
authors.forename: Ladan
authors.initials: L
authors.lastname: Espandar
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Torres
authors.forename: Angel
authors.initials: A
authors.lastname: Alvarez-Barcia
authors.forename: Roberto
authors.initials: R
authors.lastname: Cantalapiedra-Rodriguez
authors.forename: Carmen
authors.initials: C
authors.lastname: Martinez-Garcia
authors.forename: Jesus
authors.initials: J
authors.lastname: Merayo-Lloves
mesh_terms: D000287:Administration, Topical; D000477:Alkylating Agents / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D002645:Chickens; D003131:Combined Modality Therapy; D003315:Cornea / Q000187:drug effects* / Q000473:pathology / Q000601:surgery*; D060527:Corneal Keratocytes / Q000473:pathology; D004357:Drug Synergism; D000431:Ethanol / Q000633:toxicity; D020287:In Situ Nick-End Labeling; D016685:Mitomycin / Q000008:administration & dosage / Q000633:toxicity*; D023421:Models, Animal; D058628:Myofibroblasts / Q000473:pathology; D018903:Photorefractive Keratectomy; D014945:Wound Healing / Q000502:physiology*
chemical_list: D000477:Alkylating Agents; D000431:Ethanol; D016685:Mitomycin