Objectives: The aim of the present study was to investigate the changes which occur to the arterial wall following cryopreservation and thawing and to determine whether these changes are reversible after a week of culture in an organ bath.
Materials and methods: Rat iliac arterial segments were cryopreserved. Once thawed, the arterial segments were cultured for a period of 0, 1, 2, 4 or 7 days. Freshly isolated rat iliac vessels cultured for 7 days served as the control group. Evaluation was made of ultrastructural changes, the expression of metalloproteinase activity (MMP-1, MMP-3 and MMP-9) and the apoptotic state of cells.
Results: The freezing-thawing process induced damage to the arterial segments compared to fresh control vessels. After 1 week of culture, arteries showed a high degree of tissue degeneration. Only a few individual endothelial cells remained on the luminal surface. There was a gradual increase in the proportion of apoptotic cells. The sequential expression of MMP-1 during the first 2 days and subsequent expression of MMP-3 and MMP-9 were of most significance.
Conclusions: Cryopreservation induced damage to the vessels which could not be reversed by organ culture. The changes observed in the expression of metalloproteinases may be indicative of the degenerative process which occurs in the extracellular matrix.