Influence of the Difference in Temperature and Duration of Storage on the Rejection of Cryopreserved Rat Tracheal Homograft

Won, Taehee; Jang, Ji Won; Ahn, Jae Ho

Abstract

BACKGROUND: It has been known that cryopreservation can reduce the rejection in the tracheal homograft implantation with preserving its viability. However, the effect of difference in the temperature and duration of storage on the rejection has not been proven. Therefore we investigated the effects of storage temperature and duration on the rejection of cryopreserved rat tracheal homograft. MATERIAL AND METHOD: Twenty four rat's tracheas were harvested from rats and stored in -80degrees C deep freezer and -196degrees C nitrogen tank for 1, 3, and 6 months respectively. The forty eight tracheal segment(each trachea divided into two) were implanted in peritoneal cavity with omental wrapping. The 48 recipient rats were divided into six groups(8 rats/group). Group 1, 3, and 5 were rats implanted with trachea of preservation in -80degrees C for 1 month, 3 months and 6 months respectively. And Group 2, 4, and 6 were rats implanted with trachea of preservation in -196degrees C for 1 month, 3 months and 6 months, respectively. Group 7(n=8) was control group that fresh trachea without cryopreservation was implanted. After 14 days, the implanted tracheas were harvested and the degrees of rejection were investigated with moncellular infiltration and luminal obliteration of trachea by fibrous tissue. RESULT: Most of the tracheas in each group showed moderate or severe degree of moncellular infiltration and there was no statistically significant difference between the 7 groups. The luminal obliterations were less in groups 1,2,3,4,5, and 6 compared to group 7, however, there was no statistical difference. The cartilages were maintained their viability even in the severe perichondral moncellular infiltration in all groups.
CONCLUSION
There was no difference in rejection between groups of different storage temperature and duration. It is supposed that proper use of immunosuppressants is required even after cryopreserved tracheal homograft implantation.