连续冻融对硫酸软骨素保存心脏瓣膜的影响

Influence of successive freeze-thawing on cardiac valves cryopreserved in liquid nitrogen with chondroitin sulfate

①目的观察舍硫酸软骨紊（cs）的液氮冷冻保存的心脏瓣膜在连续冻融下细胞活力及瓣膜组织学结构的变化。②方法选取60只兔主动脉随机分成6组，每组10只并经灭茵处理。对照组灭茵后立即检测；实验Ⅰ—Ⅴ组转入装有7．5％硫酸软骨素的抗冻剂的无茵冻存管内。实验Ⅰ、Ⅲ、V组分别于瓣膜保存4、16、32周后取出复温，然后立行Ⅰ检测。实验Ⅱ、Ⅳ组分别于4、16周后取出，解冻后在室温下放置10min，更换保存液后再次按照程序控速降温法冷冻保存，4周后再次取出复温，然后检测。③结果实验I、Ⅲ、Ⅴ组瓣膜组织学结构损伤较轻。与对照组相比，实验Ⅰ组细胞活力下降不明显（P〉0．05）；实验Ⅲ、Ⅴ组细胞活力明显低于对照组（P〈0．05），实验Ⅰ、Ⅲ、Ⅴ组之间比较，细胞活力差异无显著性（P〉0．05）。实验Ⅱ、Ⅳ组瓣膜组织学结构损伤较重。实验Ⅱ、Ⅳ组细胞活力明显低于对照组和实验Ⅰ、Ⅲ、Ⅴ组（P〈0．05）。④结论舍硫酸软骨素的液氮冷冻保存的心脏瓣膜在单次冷冻保存32周内皆可作为移植瓣膜选用；连续冻融的瓣膜，不管首次保存时间多短，一旦融化则不可再用，即便是用程序控速降温法并加入辅保护剂硫酸软骨素的冷冻液保存的亦无法再用。

Objective To investigate the influence of successive freeze - thawing on the histological structure and cellular vi ability of eryopreserved homograft cardiac valves in liquid nitrogen with ehondroitin sulfate （ CS ）. Methods Sixty rabbit aortic valves were randomLy divided into control and experiment groups （ I - Ⅴ ） （n= 10）. All the valves were germicidal treated. Then, the cytoactive of endothelial cells in control group was immediately examined and the specimens were observed under light and elec tron microscopes. The experiment groups were eryopreserved in liquid nitrogen contained 7.5% volume percentage of CS. In group I, III and V, the valves were thawed and examined after 4,8,12 weeks respectively. In group Ⅱ and IV, the valves were thawed after 4 ＇and 8 weeks respectively and were eryopreserved again after being left at room temperature 10 minutes. The two groups were thawed again after 4 weeks and examined. Results Slight morphologic changes occurred in group I, III and V while significant mor phologic damages in GroupⅡ and IV. Compared with the control, cytoactive of Group I was not significantly declined （ P 〉 0.05 ） and eytoaetive of Group III/rod V were significantly delined （ P 〈 0.05）. Compared with the control, Group I , m and V, cy tozetive of Group Ⅱ and IV was significantly declined （ P 〈 0.05）. Conclusion Within 32 weeks after single eryopresezvation, the valves have better availability. While successive freeze - thawing do harm to histological structure and cellular viability of eryopre served homograft cardiac valves, these valves have little availability. It is not necessary to reeryopreserve the once - eryopreserved and thawed rabbit aortic valves for use.