title: Effects of topical vitamin E on keratocyte apoptosis after traditional photorefractive keratectomy.
abstract: OBJECTIVE
  To evaluate the keratocyte apoptosis and effects of topical vitamin E on keratocyte apoptosis after photorefractive surgery.
  
  
  METHODS
  Rabbits were divided into 7 groups, and all groups were compared with controls after epithelial scraping, epithelial scrape and photorefractive keratectomy (PRK) (traditional PRK), transepithelial PRK, production of a corneal flap with microkeratome and laser-assisted in situ keratomileusis (LASIK). The effects of topical Vitamin E treatment were investigated in the traditional PRK group. The terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay (to detect DNA fragmentation in situ) and light microscopy have been used to detect apoptosis in rabbit cornea.
  
  
  RESULTS
  Transepithelial PRK induced minimal keratocyte apoptosis, less than in all other refractive surgical procedures. The greatest amount of keratocyte apoptosis was observed after traditional PRK (p = 0.001), therefore we tested the effects of topical vitamin E in this group. The number of apoptotic keratocytes significantly reduced after vitamin E therapy (p < 0.005).
  
  
  CONCLUSIONS
  Keratocytes undergo apoptosis after refractive surgery in response to mechanical epithelial removal, preparing of corneal flap and excimer laser stromal photoablation. The topical application of vitamin E immediately after surgery can prevent keratocyte apoptosis, and this result suggests that free radicals may be partly responsible for keratocyte apoptosis after excimer laser keratectomy.
authors.affiliation: Department of Ophthalmology, Gazi University Medical School, Ankara, Turkey. bilgihan@med.gazi.edu.tr
authors.forename: K
authors.initials: K
authors.lastname: Bilgihan
authors.forename: U
authors.initials: U
authors.lastname: Adiguzel
authors.forename: C
authors.initials: C
authors.lastname: Sezer
authors.forename: G
authors.initials: G
authors.lastname: Akyol
authors.forename: B
authors.initials: B
authors.lastname: Hasanreisoglu
mesh_terms: D000287:Administration, Topical; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D003319:Corneal Stroma / Q000166:cytology / Q000601:surgery*; D004247:DNA / Q000032:analysis; D005347:Fibroblasts / Q000187:drug effects*; D020287:In Situ Nick-End Labeling; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D009883:Ophthalmic Solutions; D018903:Photorefractive Keratectomy; D011817:Rabbits; D017382:Reactive Oxygen Species; D054140:Refractive Surgical Procedures; D013524:Surgical Flaps; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D009883:Ophthalmic Solutions; D017382:Reactive Oxygen Species; D014810:Vitamin E; D004247:DNA