Experimental Research On Corneal Cryoreservation Of The Whole Eyeballs

Background: Corneal cryopreservation technique is a kind of preservation method for corneal graft established by Capella in 1965, which can make cornea occupy"quiescence condition". The viability of corneal endothelial cells does not derease with the storage time."Moist-chamber storage at 4℃is a simple way to preserve the whole eyeball, by which the grafts are easily transported and not easy to be contaminated.But the viability of the corneal endothelia would be preserved for a short time. We'll combine the advantages of the two methods above to develop a new effective method to long-term preserve cornea.Objective: To develop the best mode of corneal cryopreservation technique and research the factors that affect the corneal endothelium viability at low-temperature.Methods: Eighty rabbits eyeballs were divided into 8 groups according to the methods of the injection of DMSO into the anterior chamber , the cool balancing time, freezing rate, the thawing condition.The storage time for these corneas was 30d. 10 fresh rabbit eyes were as the controle. ESR and morphology of the corneas were evaluated by trypan-alizarin red staining.Then the electron microscope examination and the histochemical staining of SDH and ATPase were carried out and compared with the controle group.Results: The best group with the highest ESR was selected which techniques were as follows.the aqueous fluid of the anterior chamber was evacuated ,followed by the injection of 7.5% (V/ V) DMSO and cool balance in refrigerator at 4℃for 30 min during which re-injection of DMSO was taken two times. Then the eyeballs were storaged in liquidnitrogen at -196℃after rate-freezing 30min at-30℃and 30 min at -80℃successively.The eyeballs were thawed in the water bath at 40℃. The ESR of the selected group was 87.53% on average which was similar to that of the controle group(98.20%).The mean value of IOD in the selected group was 133.0±19.2 which was similar to that(134.1±24.0) in the controle group. light color ,t=0.1,compared with the best freezing group and the contrast group (P>0.05).Conclusion: Corneal cryopreservation technique of the whole eyeball is simple, convenient and effective method which is suitable for the penetrating corneal transplantation.