<Original Articles>Evaluation of Oxygen Necessity during Hypothermic Liver Perfusion

Abstract

Need of oxygen by the liver during hypothermic perfusion was evaluated using isolated perfusion model. Livers were perfused by a continuous perfusion system with oxygen saturated perfusate or nitrogen saturated perfusate, or simply stored for 12 hours at 5°C. Quality of individual liver was assessed at one hour after normothermic reperfusion. Tissue edema was significant in all experimental groups, but the extent of which was much higher in nitrogen and simple cold storage groups. AST, ALT, LDH and PNP in the perfusate at the end ofnormothermic reperfusion were significantly higher in nitrogen and simple storage groups and those of oxygen group were similar to the control. Tissue adenine nucleotide and purine catabolite concentration in oxygen group was almost identical to the control at the end of hypothermic preservation, while ATP and energy charge in nitrogen and simple cold storage groups were significantly low . Conjugated dienes before and after reperfusion showed no difference in any groups, indicating no involvement of free radical injury on reperfusion in this asanguineous perfusion model. These resuts suggest that continuous supply of oxygen is necessary for liver preservation even though the temperature is lowered to inhibit celluar metabolism.

肝移植における保存臓器の障害が, 低温, 虚血, 再灌流時の活性酸素のいずれの要因によるものかを調べるため, ラット肝灌流モデルを用いて実験を行った. ラット肝を Simple Cold Storage 法にて保存もしくは, 酸素で飽和した灌流液または窒素により酸素を置き換えた灌流液をもちいて5度で12時間持続灌流し, 37度1時間再灌流にて評価した. 組織浮腫は窒素加および Simple Cold Storage 群で著明であった. 再灌流後の灌流液中 AST, ALT, LDH, および PNP は窒素加とよび Simple Cold Storage 群で有意に高く, 酸素加群で、はコントロールと有意差を認めなかった. 低温保存後の組織中 Adenine Nucleotide Profile は酸素加群とコントロール群がほぼ一致し, 窒素加および Simple Cold Storage 群においては ATP 量, Energy Charge が有意に低値を示した. Conjugate Dienes は再灌流前後において有意の増加を示さず, 再灌流時の活性酸素の関与は認められなかった. これらの結果より保存中, および再灌流直後の障害は主に低酸素によることが示唆された.