Biological Activity Study Of Cryopreserved Composite Tissue With Different Thawing Methods

BACKGROUND: With the rapid development of industrialization andmodernization of the society, caused by trauma to the limb (finger) in patients withincreasing. The proportion of patients due to systemic multi-trauma condition ofinstability can not be the emergency line replantation to be in stable condition afterlimb (finger) is often the ability to save technology, but relevant to have necrosis, thelose replanted opportunity, these patients tend to lose some of the features and evendaily living, a heavy burden to the society and the family. From off limbs securelystored until the patient’s condition is stable, can still line the limbs (finger)replantation, will this part of the patient to bring the Gospel. In addition, clinicalreports of successful transplantation of allogeneic tissue, we hope that willsuccessfully save these limbs (fingers) and the establishment of the limb librariesprovide opportunities for replantation of patients with limbs missing. Compositetissue and the whole limb preservation has been a pressing problem of the field ofregenerative medicine and microsurgery, mainly in the cooling-rewarming process ofice crystal formation and aggregation of ice crystals in the process of being undonetemperature form will be cells caused fatal injury; composite tissue preservation andtransplantation success of the blood supply is a key factor. Based on the abovebackground, the proposed three kinds of rewarming to cryopreserved composite tissuethawed, the activity of vascular endothelial cells to identify the composite tissue in adeep-frozen thawed rewarming methods for composite tissue preservation andtransplantation to provide a certain basis.OBJECTIVE: To compare three different rewarming methods of deep-frozencomposite tissue vascular activity to identify a minimum vascular injury in compositetissue rewarming methods.METHODS:20New Zealand white rabbits were selected in our test, the y wererandomly divided into four groups.The rabbits hind legs are cut as the specimens(butthe control group without any treatment). Three experimental groups are stored in the liquid nitrogen for7days after after gradient freezing. The test specimens are thawedby three different methods(at37℃for thawing (group A), air thawing (group B),-20℃ice thawing (Group C)).The histological changes are observed by lightmicroscopy and immunohistochemical methods,and the result are analysised by thestatistical methods.RESULTS: The result of optical microscope: There is a large loss in endothelialcells and deformation in smooth muscle cells in Group A and B. And Group C is closeto the control group,which is well preserved to the endothelial cells and smoothmuscle cells. The result of Immunohistochemistry: There was patchy weak expressionin vascular endothelial after3different kind thawing methods. Among the3groups,-20℃ice thawing (Group C) is closer to the control group in VEGF expression, andit is higher than the other2thawing methods(at37℃for thawing (group A), airthawing (group B)（p<0.05）.CONCLUSIONS:1. There are different damage on the vascular activity of the composite tissueafter programmed freezing-thawing process.2. Among the3kinds of thawing method (37℃water bathing、air temperatureand-20℃ice), the method of-20℃ice have the least impact on the activity ofvascular endothelial.