Zhu Q, Layne J R, Claydon M, Hicks G L, Wang T
Department of Surgery, University of Rochester, New York 14642.
Cryobiology. 1992 Aug;29(4):478-84. doi: 10.1016/0011-2240(92)90050-c.
This study investigated the effect of thawing rate on the preservation of frozen isolated rat hearts. The hearts were flushed with a hyperosmotic cardioplegic solution, CP-14/EtOH (1.15 Osm/kg), frozen at a rate of 0.18 degree C/hr for 6 h to -3.2 degrees C. Thereafter, the hearts were thawed at rates ranging from 0.08 to 1.1 degrees C/min for 1 to 14 min until the heart temperature reached -2.1 degrees C, the melting point (MP) of the flush solution; then they were held at -1 degree C for 11 to 24 min so that the total thaw time was 25 min. Post-thaw function was assessed by working reperfusion and expressed as percentage of unstored control function. Cardiac output (CO) and other hemodynamic performance showed biphasic responses to the thaw rate. At 0.08 degree C/min rate, CO recovered to 29.1 +/- 4.1 ml/min (40.8 +/- 5.8% of control). Thawing at 0.13 degree C/min enhanced the recovery of CO to 60.5 +/- 4.9%. Between 0.13 and 0.34 degree C/min, recovery was statistically insignificant. Faster thawing at 0.59 and 1.1 degrees C/min caused progressively less recovery. Overall, 0.13 degree C/min offered the highest recovery. In conclusion, function in slowly frozen heart is intimately affected by the thawing rate; there was an optimal intermediate thawing rate and both too slow and too fast thawing were detrimental.
本研究调查了复温速率对冷冻保存的离体大鼠心脏的影响。心脏先用高渗心脏停搏液CP-14/乙醇（1.15 Osm/kg）冲洗，然后以0.18℃/小时的速率冷冻6小时至-3.2℃。此后，心脏以0.08至1.1℃/分钟的速率复温1至14分钟，直至心脏温度达到冲洗液的熔点（MP）-2.1℃；然后将其在-1℃保持11至24分钟，使总复温时间为25分钟。复温后的心脏功能通过工作再灌注进行评估，并表示为未保存对照功能的百分比。心输出量（CO）和其他血流动力学性能对复温速率呈现双相反应。以0.08℃/分钟的速率复温时，CO恢复至29.1±4.1毫升/分钟（为对照的40.8±5.8%）。以0.13℃/分钟的速率复温可使CO恢复率提高至60.5±4.9%。在0.13至0.34℃/分钟之间，恢复率在统计学上无显著差异。以0.59和1.1℃/分钟的速率更快复温导致的恢复逐渐减少。总体而言，0.13℃/分钟的复温速率可实现最高的恢复率。总之，缓慢冷冻心脏的功能受复温速率的密切影响；存在一个最佳的中间复温速率，复温过慢和过快均有害。
