Freezing preservation of the mammalian cardiac explant. V. Cryoprotection by ethanol.
We studied the colligative cryoprotective effect of ethanol (EtOH) in preserving the isolated rat heart frozen at -3.4 degrees C or unfrozen at -1.4 degrees C. Addition of 4.7% (v/v) EtOH to a cardioplegic solution, CP-14, raised the osmolality from 280 to 1100 mOsm/kg H2O and lowered the melting point from -0.52 to -2.1 degrees C. Freezing of the cardiac explant at -3.4 degrees C for 6 h resulted in 34.3 +/- 1.9% of the tissue water as ice; recovery of cardiac output (CO) was 50%. Polyethylene glycol, which at 5% (w/v) has been shown to cryoprotect the hearts during freezing at -1.4 degrees C, did not improve the protective effect of 4.7% EtOH. CP-14 + 4.7% EtOH did not freeze at -1.4 degrees C. After 6 h storage, CO in hearts flushed with CP-14 + 4.7% EtOH oxygenated with 95% O2/5%CO2 returned to almost control level and was much higher than that in hearts flushed with 100% O2 saturated-CP-14 + 4.7% EtOH. Storage of 8 and 12 h reduced CO to 87 +/- 9 and 60 +/- 5% of control. By employing EtOH as a colligative cryoprotectant, we preserved the adult mammalian heart frozen at -3.4 degrees C or unfrozen at -1.4 degrees C, suggesting that this small molecular weight, penetrating substance may be a suitable cryoprotectant for long-term storage of the cardiac explant at high subzero temperatures.
Wang
T
T
Department of Surgery, University of Rochester, New York 14642.
Banker
M C
MC
Claydon
M
M
Hicks
G L
GL
Layne
J R
JR
D000818:Animals; D002302:Cardiac Output; D015925:Cryopreservation / Q000379:methods*; D000431:Ethanol / Q000633:toxicity; D005069:Evaluation Studies as Topic; D006321:Heart / Q000187:drug effects / Q000502:physiology; D007053:Ice; D066298:In Vitro Techniques; D008297:Male; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D051381:Rats; D017207:Rats, Sprague-Dawley; D013696:Temperature; D013997:Time Factors
D007053:Ice; D000431:Ethanol; D011092:Polyethylene Glycols