The Viability, Structure, and Mechanical Properties of Cryopreserved Rabbit Carotid Artery

摘要

New techniques have been developed for cryopreservation of arteries for use in transplantations or bypass surgery. In our experiments, rabbit carotid arteries were cryopreserved in a cryoprotective medium containing 1.5 M 1,2- propanediol (PROH). After storage in liquid nitrogen for over 10 days, the frozen arteries were thawed slowly in an ice bag that had been pre-cooled in liquid nitrogen to prevent thermal stress and fracture. Fresh carotids were used as normal controls. The fresh and cryopreserved arteries were cultured. The growth of smooth muscle cells (SMCs), the development of endothelial cells (ECs), the integrity of carotid walls (the elastic lamellae or fibers), and the mechanical properties of arteries (elastic modulus and fracture strength) were investigated. The results showed that SMCs survived cryopreservation. It took approximately the same amount of time (2436 h) for the SMCs of cryopreserved arteries to regenerate as those of the fresh arteries. After cryopreservation, only a small number of ECs survived. The mechanical properties and strength of cryopreserved arteries decreased significantly. After in vitro perfusion, the surviving ECs in carotid arteries exfoliated, and some of the SMCs necrosed. The internal elastic fibers and collagen showed various degrees of damage/cracking; and the mechanical properties and strength further decreased. In conclusion, mechanical strength and cell viability of arteries can change significantly after the cryopreservation process. Data from this study on these changes will be helpful for researchers and medical doctors when using cryopreserved arteries in research or clinical transplantation.