降温速度对冷冻保存异体小静脉通畅率的影响

目的:探讨不同降温速度对异体小静脉内皮细胞代谢活性,超微结构和移植通畅率的影响。材料和方法:采用快速冷冻和二步冷冻两种不同的降温速度对异体小静脉进行冷冻,在液氮中保存48小时后施行移植。观察方法包括四唑盐还原试验、扫描电镜、静脉造影及病理检查。结果:经二步冷冻保存的异体小静脉,其代谢活性和内皮细胞形态得到良好保持,移植后排斥反应减弱,90天通畅率80％。结论:二步冷冻降温是异体小静脉冷冻保存理想的方法。

EFFECT OF FREEZING RATE ON THE PATENCY OF CRYOPRESERVED ALLOGENIC SMALL VEINS

Objective: In the prsent study, the effect of different freezing rate on the metabolic activity, ultrastructure and patency of cryopreserved-allogenic small veins was investigated. Methods: The allogenic small veins were cryopreserved in vitro either by freezing rapidly to-196℃ or by a two-step freezing schedule and then implanted into femoral venous defects after storage in liquid nitrogen for 48 hours .The allogenic small veins were observed after cryopresservation using tetrazolium test and electron microscope and analysed postoperatively by angiography and pathologic examination. Results: The metabolic activity and ultrastructure of cryopreserved allogenic small veins were well preserved by the two-step freezing procedure. There was a 80% patency rate at 90 days for such allografts with a decreased immunologic reaction. Conclusions: The two-step freezing schedule is the optimal method for cryopreservation of the small venous allografts.