液氮保存对人同种瓣组织代谢及活性的影响

目的　主要观察液氮 (- 1 96℃ )保存 1～ 2 4个月不同时间瓣膜组织葡萄糖代谢率和同位素标记的胸腺嘧啶核苷掺入量的变化 ,为临床适用的冷冻保存人同种主动脉瓣的适宜保存期限提供实验依据。方法　选取健康成年男性的主动脉瓣膜 2 0个。实验依据保存时间分为 1 0组 ,Ⅰ组为新鲜对照组 ,Ⅱ～Ⅹ组分别为冷冻保存 1～ 2 4个月瓣膜。新鲜瓣膜取材后直接供实验用 ,冷冻组各瓣膜缓慢降温 (1℃·min- 1 ) ,液氮中保存 ,快速复温。瓣膜置入培养液 2 4h ,置入前后分别测定培养液中的葡萄糖含量并计算其差值。同位素测定标本加入氚标记的胸腺嘧啶核苷 ,做CBPM计数 ,计算每mg组织3H TdR掺入量。结果　新鲜瓣膜组葡萄糖消耗量和3H TdR掺入量均最高 ,冷冻保存组随液氮保存时间延长 ,组织的葡萄糖消耗量和3H TdR掺入量逐渐减低 ;冷冻保存 1～ 1 5个月瓣膜葡萄糖代谢率与新鲜瓣膜组比较无统计学意义 ,冷冻保存 1 8～ 2 4个月瓣膜葡萄糖消耗量明显减低 (P <0 .0 5 ) ,冷冻保存 1 2～ 2 4个月瓣膜3H TdR掺入量较对照组明显减低 (P <0 .0 5 )。结论　液氮保存对人同种瓣膜组织葡萄糖代谢率和胸腺嘧啶核苷掺入量有一定影响 ,其程度随保存时间增长而加重 ,液氮保存 1 5～ 2 4个月瓣膜组织代谢率明显减低 ,因此瓣膜耐久性可?

Influence of liquid nitrogen on metabolism and tissue viability of human aortic valve homografts

Objective To observe the tissue glucose utilization and 3H TdR incorporation of human aortic valves after cryopreserved in-196?℃ liquid nitrogen. Methods Twenty valves, which were harvested from healthy adult donors, were randomly divided into 10 groups: Group I, the control group, was fresh valve; Group Ⅱ Ⅹwere valves preserved in liquid nitrogen at month(s) of 1,3,6,9,12,15,18,21,24,respectively. Fresh valves were examined directly. All the cryopreserved valves were thawed by the method of immersing in 37?℃ saline pool. All specimens were divided into two portions. One portion was examined for tissue glucose consumption. Another portion was measured for 3H TdR incorporation. Glucose content was measured in each specimen tested for glucose utilization pre and post incubating in the culture medium at 37?℃. Valve tissues tested for isotopic measurement were incubated in RPMI 1640 containing 3H TdR for 14～16 hours at 37?℃, then scintillation fluid were added to count the CBPM.Results The fresh valves had the most rates of glucose consumption and 3H TdR incorporation. Valves of group Ⅷ Ⅹ significantly decreased in glucose consumption compared with that of fresh valve (13.9～11.2? vs .26.5, P <0.05). 3H TdR incorporation was decreased markedly in group Ⅵ Ⅹcompared with that of the fresh valves (100.9～20.6? vs .175.1, P <0.05).Conclusion Long term cryopreservation in liquidnitrogen can reduce the tissue glucose utilization and 3H TdR incorporation of human valves. Thelonger the cryopreserved duration, the lower the rates of glucose consumption and 3H TdR incorporation. Valves preserved for over 15 months have lower glucose utilization and valves preserved for over 12 months decrease markedly in 3H TdR incorporation. The durability of those valves in clinical use would be shortened correspondingly.