The structural and cellular viability in cryopreserved rabbit carotid arteries.
OBJECTIVE
We investigated the histological and mechanical changes in addition to viable cellular recovery in cryopreserved blood vessels.


METHODS
Rabbit carotids were cryopreserved in a cryoprotective medium containing 1.5 M of 1,2-propanediol (PD) and then were thawed slowly in an ice bag that had been precooled in liquid nitrogen. Fresh carotids were used as the control. The fresh and freeze-thawed arteries were cultured for the growth of vascular smooth muscle cells (VSMCs). The freeze-thawed arterial tissues were perfused in vitro for 6, 12, or 24 h, respectively, to assess the integrity of carotid walls and the mechanical properties.


RESULTS
The results showed that it took almost the same time (24 approximately 36 h) for the VSMCs of the PD-cryopreserved arteries to regenerate as those from the fresh arteries. Their growing speeds also were similar. On the contrary, Me2SO-cryopreserved (1.5 M) arteries were unable to regenerate VSMCs in culture. After freeze-thawing, the mechanical properties decreased significantly (P < 0.003 for elastic modulus and P < 0.001 for fracture strength). After in vitro perfusion of the freeze-thawed carotid arteries, all of the survived endothelial cells fell off, and some of the VSMCs denaturalized or necrosed. The internal elastic fibers and collagen showed various degrees of cracking. The mechanical properties were decreased (P < 0.05).


CONCLUSIONS
Our findings demonstrate that the PD-containing cryoprotective medium can preserve regenerative capacity of VSMCs, which makes it a useful technique for viable VSMC recovery. However, the freeze-thawing process and the in vitro perfusion caused serious disruption in the arterial mechanical properties, rendering the cryopreserved blood vessels less useful for vessel reconstruction.
Wang
Peitao
P
Department of Thermal Science and Energy Engineering, University of Science and Technology of China (USTC), Hefei, China. peit_wang9@ustc.edu
Shu
Zhiquan
Z
He
Liqun
L
Chen
Shuxia
S
Wang
Yuzhen
Y
Li Wang
Xing
X
D000818:Animals; D001696:Biomechanical Phenomena; D002339:Carotid Arteries / Q000033:anatomy & histology* / Q000166:cytology*; D002470:Cell Survival; D015925:Cryopreservation; D042783:Endothelial Cells; D005260:Female; D008297:Male; D011817:Rabbits