title: Light and transmission electronic microscopy evaluation of lyophilized corneas.
abstract: OBJECTIVE
  Cornea storage for longer periods is still a challenge for corneal surgeons. The purpose of this study was to find a method to lyophilize corneas for anterior lamellar transplant and to evaluate them by light and transmission electronic microscopy.
  
  
  METHODS
  Corneal flaps were created by using a microkeratome. Corneas were lyophilized with a cryoprotectant (2.3 mol sacarousis for 40 minutes) and without a cryoprotectant in a lyophilization machine (Modulyon D). The corneas were rehydrated with distilled water, balanced saline solution (BSS), and phosphate-buffered saline, after which they were evaluated by microscopy. A cornea that did not undergo lyophilization served as a control.
  
  
  RESULTS
  Lyophilization without a cryoprotectant did not preserve the corneal structure. This finding was also observed when lyophilizing and rehydrating the corneas with distilled water or phosphate-buffered saline. We found that lyophilizing corneas and rehydrating them with 11 mL of BSS for 30 minutes preserved the general corneal structure, the parallelism of the collagen fibers, the Bowman layer, and the epithelial basement membrane for 15 and 30 days and for as long as 1 year or more.
  
  
  CONCLUSIONS
  Lyophilization with sacarousis and rehydration with BSS may be a good method for anterior lamellar transplantation.
authors.affiliation: Federal University of São Paulo, São Paulo, Brazil. roberta.farias@yahoo.com.br
authors.forename: Roberta J M
authors.initials: RJ
authors.lastname: Farias
authors.forename: Luciene B
authors.initials: LB
authors.lastname: Sousa
authors.forename: Acácio A S
authors.initials: AA
authors.lastname: Lima Filho
authors.forename: Andréa C S
authors.initials: AC
authors.lastname: Lourenço
authors.forename: Márcia H
authors.initials: MH
authors.lastname: Tanakai
authors.forename: Edna
authors.initials: E
authors.lastname: Freymuller
mesh_terms: D003315:Cornea / Q000648:ultrastructure*; D003319:Corneal Stroma; D003451:Cryoprotective Agents / Q000627:therapeutic use*; D005612:Freeze Drying / Q000379:methods*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D009926:Organ Preservation / Q000379:methods*; D013524:Surgical Flaps
chemical_list: D003451:Cryoprotective Agents