【原】等容冰点下温度到-8℃及78 MPa条件下的心脏保存

罂粟花anesthGH 2021-07-21

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Preservation of rat hearts in subfreezing temperature isochoric conditions to -8℃ and 78 MPa

背景

等容冰点下温度（体积恒定）保存是一种保存细胞和器官的新方法。这项研究对新的心脏保存方法做出首次评价，并对合适的保存参数进行初步概述。

方法

为了建立进一步研究其基础，把大鼠心脏分别在0℃（大气压-0.1MPa）、-4℃（41 MPa）、-6℃（60 MPa）、-8℃（78 MPa）的UW液中保存1小时。使用Langendorff灌注模型和组织学检查评估心脏的活力。

结果

在-4℃（41 MPa）与冰点下保存的心脏，其生理机能相当、组织学损伤评分没有统计学差异。然而，与传统的4℃低温保存相比较，在-4℃（41 MPa）条件下保存的心脏，细胞间质水肿减轻，表明血管通透性显著降低。在-6℃（60 MPa）条件下保存的心脏，细胞广泛膨胀及水肿，而在-8℃（78 MPa）条件下，细胞形态严重紊乱。据我们所知，在不使用冷冻保护剂的情况下，这是第一例哺乳动物器官在低于冰点温度下的存活。降低保存温度会降低新陈代谢并提高器官保存质量，这些结果表明，在-4℃、低到中等大气压下提高供心冷保存质量还是可能的。低温（-6℃或更低）与其相关的压力增大可能导致组织损伤。

结论

冰点下温度器官保存方法应该还可以改进，压力和温度相结合可以保持低温与新陈代谢降低所带来的益处，而副作用相对较少。

原始文献摘要

Abstract

Isochoric (constant volume) preservation at subfreezing temperatures is being investigated as a novel method for preserving cells and organs. This study is a first initial effort to evaluate the efficacy of this method for heart preservation, and to provide a preliminary outline of appropriate preservation parameters. To establish a baseline for further studies, rat hearts were preserved in a University of Wisconsin (UW) intracellular solution for one hour under isochoric conditions at: 0℃ (atmospheric pressure- 0.1 MPa), - 4 ℃ (41 MPa), - 6 ℃ (60 MPa) and -8℃C (78 MPa). The viability of the heart was evaluated using Langendorff perfusion and histological examination. The physiological performance of hearts preserved at -4℃ (41 MPa) was comparable to that of a heart preserved on ice at atmospheric pressure, with no statistically significant difference in histological injury score. However, hearts preserved at -4℃ displayed substantially reduced interstitial edema compared to hearts preserved by conventional hypothermic preservation in UW on ice at atmospheric pressure, suggesting significant protection from increased vascular permeability following preservation. Hearts preserved at-6℃ (60 MPa) suffered injury from cellular swelling and extensive edema, and at -8℃(78 MPa) hearts experienced significant morphological disruption. To the best of our knowledge, this is the first publication showing that a mammalian organ can survive low subfreezing temperatures without the use of a cryoprotective additive. Lowering the preservation temperature reduces metabolism and improves preservation quality, and these results suggest that improvements in preservation are possible at subzero temperatures with low to moderate pressures observed at -4℃. Notably, tissue damage was observed at lower temperatures (-6℃or below) accompanying further elevation of pressure associated with isochoric preservation that may prove detrimental. Therefore, subfreezing temperature isochoric preservation protocols should
optimize, a combination of temperature and pressure that will minimize the negative effects of elevated pressure while retaining the beneficial effect of lower temperatures and reduced metabolism.