Light and transmission electronic microscopy evaluation of lyophilized corneas.
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.
Farias
Roberta J M
RJ
Federal University of São Paulo, São Paulo, Brazil. roberta.farias@yahoo.com.br
Sousa
Luciene B
LB
Lima Filho
Acácio A S
AA
Lourenço
Andréa C S
AC
Tanakai
Márcia H
MH
Freymuller
Edna
E
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
D003451:Cryoprotective Agents