Effects of different cryopreservation methods on the ultrastructure and viability of amniotic membrane / 中国组织工程研究

ABSTRACT

BACKGROUND: There are currently many cryopreservation methods for the aminotic membrane, which have varying effects on the ultrastructure and biological activity of amniotic membrane, but on no one is effective. OBJECTIVE: To compare the effects of different cryopreservation methods on the ultrastructure and viability of aminotic membrane and to seek the ideal cryopreservation method. METHODS: Aminotic membrane separated from the fresh placenta was preserved respectively with deep-frozen cryopreservation and vitrification, and everyway was run for 3 and 6 months. Fresh aminotic membrane was used as control. The ultrastructure of aminotic membrane was observed by transmission electron microscopy, and the viability of aminotic membrane was assessed by microcomputer analysis system for biological oxygen consumption, and immunohistochemical staining combined with image analysis system was used for lactate dehydrogenase activity. RESULTS AND CONCLUSION:After 3 and 6 months of crypreservation, the damage to the ultrastructure of aminotic membrane by vitreous cryopreservation was slighter than that of amniotic membrane cryopreserved at-80℃. Compared with the fresh aminotic membrane, the gray value of lactate dehydrogenase and partial pressure of oxygen were significantly decreased in the cryopreserved aminotic membrane by deep-frozen cryopreservation at 3 and 6 months (P < 0.05) and by vitreous cryopreservation at 6 months (P < 0.05), but there was no statisticaly significant difference in the change rate of oxygen partial pressure and the gray value of lactate dehydrogenase between the fresh aminotic membrane and the cryopreserved aminotic membrane by vitreous cryopreservation at 3 months. The present study led to the conclusion that vitreous cryopreservation protocol alows to not only maintain the integrity of AM, but also to preserve the viability of the cels. So the vitreous cryopreservation is superior to the deep-frozen cryopreservation for cryopreservation of aminotic membrane.