An experimental research on cryopreserving rabbit trachea by vitrification.

Vitrification is a promising alternative to tissue preservation, in which the tissue is permeated with cryoprotective agents (CPAs) in order to circumvent the hazardous effects associated with ice formation. In this study, we evaluate the effect of vitreous cryopreservation of rabbit trachea, by comparing vitrification procedure with conventional computer-programmed slow freezing approaches. Harvested rabbit trachea were tailored and divided into groups and cryopreserved by vitrification and programmed freezing, respectively. The morphology and ultrastructure of the thawed tracheal fragments including HE dyes, terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) staining, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were studied to assess the integrity of the tracheal fragments. Morphological studies demonstrated that both cryopreservation procedure retained the integrity of trachea, both epithelial cells, cilia and cartilage cells were in good shape. Compared with slow freezing methods, vitrification was less detrimental to cartilage cells and had a higher survival rate of chondrocytes and coverage of epithelium and cilia. Therefore, vitrification procedure can be a more satisfactory method to preserve trachea and the survival of chondrocytes in situ in cartilage tissue is adequate and respiratory epithelium is soundly present.