Cryocornea - toward enhancing the capacity and throughput of ex vivo corneal model

Objective: The objective of this study was to investigate the effects of the concentration of two intracellular (i.e. propylene glycol and glycerol) and four extracellular (i.e. dextran, hydroxypropyl methylcellulose, polyvinylpyrolidone, trehalose) cryoprotective agents as well as the effects of freeze-thawing procedures on the corneal cryoprotection.Significance: The corneal cryopreservation may possibly become the long-term storage technique of choice for collection of animal corneas suitable for ex vivo drug testing.Methods: The integrity of corneal barrier was evaluated by measurements of transepithelial electrical resistance.Results: Under the investigated experimental conditions the best result was obtained for slow freezing (2 h at -20 °C followed by 46 h at -70 °C) and rapid thawing (0.25 h at 34 °C) procedure where 20% (w/V) trehalose in Krebs Ringer buffer solution was used as extracellular cryoprotective agent.Conclusions: The selection of corneal freeze-thawing protocol as well as the optimal type and concentration of a cryoprotective agent allows the cryostorage of porcine corneal tissues with suitable TEER properties (cryocornea).