title: [Viability of corneal epithelial cells and cleavage of corneal basement after ethanol effect].
abstract: OBJECTIVE
  To evaluate the viability of corneal epithelial cells and to determine the anatomic cleavage on the epithelial basement membrane after various exposure times to 20% ethanol during epithelial flap preparation in laser-assisted subepithelial keratectomy (LASEK) in cadaver eyes.
  
  
  METHODS
  Six human cadaver eyes were exposed to 20% ethanol for 20, 30 and 40 seconds (2 eyes for each group), and another one eye was used as the control. PCNA staining was performed to determine the viability of corneal epithelial cells. Immunofluorescence staining using monoclonal antibodies against collagen VII, and immunohistological staining using monoclonal antibodies against laminin were performed to detect the anatomic location of the cleavage plane on the corneal epithelial flaps created by 20 seconds exposure to 20% ethanol in cadaver eyes.
  
  
  RESULTS
  Hematoxylin and eosin staining of epithelial flaps revealed a coherent stratified epithelium. The PCNA positive rates of the epithelial cells in the flap decreased in the 20-second group, 30-second group and 40-second group successively. Immunohistological staining to laminin was patchy in the lifted flap and the remaining corneal basement membrane. Immunofluorescence to collagen VII, the main component of anchoring fibrils remained exclusively in the corneal bed.
  
  
  CONCLUSIONS
  Viability of the epithelial flap decreased with longer time exposure to ethanol. The cleavage plane of the ethanol-treated corneal epithelial flap is located between the lamina lucida and the lamina densa of the basement membrane where laminin forms hemidesmosome.
authors.affiliation: Department of Ophthalmology, the General Hospital of Shenyang Military Command, Shenyang 110016, China. cyx156@163.com
authors.forename: Ying-xin
authors.initials: YX
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Lan
authors.forename: Ming-hong
authors.initials: MH
authors.lastname: Gao
authors.forename: Zhong-yi
authors.initials: ZY
authors.lastname: Fan
authors.forename: Fu-lin
authors.initials: FL
authors.lastname: Song
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
authors.forename: Jing
authors.initials: J
authors.lastname: Yu
mesh_terms: D001485:Basement Membrane / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002470:Cell Survival; D019573:Epithelium, Corneal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D049008:Keratectomy, Subepithelial, Laser-Assisted / Q000379:methods; D013524:Surgical Flaps
chemical_list: D000431:Ethanol