Cryopreservation of the common carotid artery of the rabbit: optimization of dimethyl sulfoxide concentration and cooling rate.

This paper describes the continuation of studies that demonstrated the suitability of CP-Tes solution as a medium for the introduction and removal of dimethyl sulfoxide in rabbit common carotid arteries and established the kinetics of cryoprotectant permeation in that tissue. In this paper we report the tolerance of rabbit common carotid artery to dimethyl sulfoxide, in concentrations up to 30% (w/w), using a technique of exposure that was designed to control osmotic stress. The maximum concentration achieved without damage was 15% (w/w). Vessels were then equilibrated with 15% dimethyl sulfoxide and cooled to -80 degrees C at 0.22, 0.69, 2.15, or 9.63 degrees C/min: they were then transferred to the gas phase of a liquid nitrogen refrigerator (temperature below -160 degrees C) for storage. Thawing was carried out in a 37 degrees C water bath. The optimum rate of cooling for these conditions was found to be 0.69 degrees C/min. The maximal recovery of contractile force in response to 10(-6) M norepinephrine was 30-40%; relaxation to acetylcholine (an endothelium-mediated function) was 80% of control, and an estimated 71% of endothelial cells survived with minimal ultrastructural change.