Arterial smooth muscle function after prolonged exposure to a medium containing dimethyl sulfoxide (Me2SO) and storage at -196 degrees C.

Changes in smooth muscle responsiveness were investigated in vitro after storage of canine femoral arteries at room temperature (21 degrees C) and in liquid nitrogen (-196 degrees C) in Krebs-Henseleit solution containing 50% fetal calf serum, 2.0 M dimethyl sulfoxide, and 0.1 M sucrose as cryoprotectants. Both contractile responses to noradrenaline and relaxant effects of bimakalim were unchanged after exposure of arterial smooth muscle preparations for 1 h to the cryomedium without freezing. However, after exposure of the tissues for increasing time periods to the cryomedium with subsequent cryopreservation the post-thaw functional recovery was progressively diminished. Optimal post-thaw functional recovery was obtained with tissues that had been frozen within 10 min of being placed in the cryomedium. The results suggest that exposure to the cryomedium without freezing is well tolerated by the arterial smooth muscle, whereas a progressive reduction of the contractile activity occurs with prolonged exposure of the preparations to room temperature cryomedium before starting the cooling process.