title: [Morphological assessment of different amniotic membrane epithelial denuding techniques].
abstract: OBJECTIVE
  To evaluate the morphological features of the amniotic membrane denuded by different techniques.
  
  
  METHODS
  Human amniotic membrane was collected at the time of delivery, fixed in increasing concentrations of glycerol (0-50% in DMEM) and preserved at -80 degrees C until the time of use. The study consisted of 4 groups: intact epithelium (control) and denuded by trypsin (2 mg/mL at 1:250), dispase (1.2 U/mL in Mg2+ and Ca2+ free Hank's balanced salt solution) or ethylenediaminetetraacetic acid (EDTA), 0.02%. Specimens were submitted to electron (scanning and transmission) microscopy analysis.
  
  
  RESULTS
  Scanning electron microscopy disclosed intact epithelium in the control group and its absence in the amniotic membranes denuded by trypsin and dispase. In those denuded by ethylenediaminetetraacetic acid there were areas with and without epithelium. When assessed by transmission electron microscopy, the epithelium was intact and firmly adhered to the basement membrane by hemidesmossomes in controls and in parts of ethylenediaminetetraacetic acid group. There were only collagen fibers in the dispase- and trypsin-treated groups.
  
  
  CONCLUSIONS
  Trypsin and dispase treatment of the amniotic membrane may cause complete denuding of the epithelium and basement membrane whereas ethylenediaminetetraacetic acid may leave some intact epithelium-areas and partially destroy the basement membrane in others.
authors.affiliation: Universidade Federal de São Paulo, São Paulo, SP, Brasil. gustavobmelo@oftalmo.epm.br
authors.forename: Gustavo Barreto
authors.initials: GB
authors.lastname: de Melo
authors.forename: José Alvaro Pereira
authors.initials: JA
authors.lastname: Gomes
authors.forename: Maria Aparecida
authors.initials: MA
authors.lastname: da Glória
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Martins
authors.forename: Edna Freymüller
authors.initials: EF
authors.lastname: Haapalainen
mesh_terms: D000650:Amnion / Q000187:drug effects / Q000648:ultrastructure*; D018929:Cell Culture Techniques; D004492:Edetic Acid / Q000494:pharmacology; D010450:Endopeptidases / Q000494:pharmacology; D004847:Epithelial Cells / Q000648:ultrastructure*; D006801:Humans; D008854:Microscopy, Electron; D014357:Trypsin / Q000494:pharmacology
chemical_list: D004492:Edetic Acid; D010450:Endopeptidases; D014357:Trypsin; C023139:dispase