不同复温速率对含硫酸软骨素的液氮保存心脏瓣膜的影响

The effects of different thawing methods on cardiac valves cryopreserved in liquid nitrogen with chondroitin sulfate

目的比较不同复温速率对液氮保存的同种异体心脏瓣膜的细胞活性及瓣膜结构的影响。方法将48只兔主动脉瓣随机分成4组，每组12只，均经灭菌处理。对照组于灭菌后立即行瓣膜细胞活力测定及组织学检查；实验Ⅰ～Ⅲ组采用程序控温降温法将瓣膜保存在含硫酸软骨素的液氮深低温中1个月后，分别采用100、30、15℃/min的平均复温速率进行复温，复温后行瓣膜细胞活力测定、光镜及电镜检查。结果3种复温方法对瓣膜均有损害，与对照组比较，实验Ⅰ组瓣膜组织学结构损伤较重，细胞活力下降显著（ P＜0.05）；实验Ⅱ组瓣膜组织学结构损伤较轻，细胞活力下降显著（ P＜0.05）；实验Ⅲ组瓣膜组织学结构改变轻微，瓣膜细胞活力下降不明显（ P＞0.05）。结论冷冻保存后将复温速率控制在15℃/min能更好地保护心脏瓣膜，经此法复温的瓣膜组织学结构损伤轻微，细胞活力佳，瓣膜可用性大。

Objective To estimate the effects of different thawing methods on the histological structure and vitali -ty of cryopreserved homograft cardiac valves in liquid nitrogen with chondroitin sulfate （ CS） .Methods A total of 48 rab-bit aortic valves were randomly divided into control group and experiment groups （Ⅰ-Ⅲ, n=12 ） .All the valves were sterilized, after which the activity of endothelial cells in control group was examined and the valve tissues were observed under light and electron microscopes .In experiment groups , valves were cryopreserved for 1 month in liquid nitrogen con-tained CS by the same programmed cooling procedure , after which the valves in Group Ⅰ,ⅡandⅢwere thawed at rates of 100, 30, 15 ℃/min, respectively.The cellular activity and pathological observation were also performed .Results Compared with controls , significant morphologic changes and cellular activity impairment were revealed in both Group ⅠandⅡ（P〈0.05）;while there was no significant difference was observed in Group Ⅲ （P〈0.05）.Conclusion The thawing rate of 15℃/min is proven the best procedure in reserving the histological structure and cellular activity of cryopr -eserved valves .