冷冻速率对猪主动脉冷冻保存效果的影响

The influence of the cooling-rate to the effect of the porcine aortic cryopreservation

目的 比较不同冷冻速率对大口径猪动脉功能及内皮的影响。方法 16头乳猪切取胸主动脉 ,每根主动脉分 3段 ,作为对照、- 1℃ min冷冻和 - 5℃ min冷冻处理。分别测定内皮细胞死亡率和血管活性药物引起的收缩、舒张程度。结果 - 5℃ min冷冻组内皮细胞死亡率明显高于 - 1℃ min冷冻组和对照组 ,P <0 0 1。冷冻组由去甲肾上腺素引起的收缩张力值明显低于未冷冻对照组P <0 0 1。- 5℃ min组明显低于 - 1℃ min组 ,P <0 0 1。冷冻组由乙酰胆碱引起的张力下降绝对值与对照组差异无显著性 ,P >0 0 5 ;舒张程度与对照组有明显差异 ,P <0 0 1。 - 5℃ min组舒张程度明显低于 - 1℃ min组 ,P <0 0 1。内皮细胞死亡率与乙酰胆碱舒张作用呈负相关 ,P <0 0 5。结论 冷冻对猪主动脉的结构和功能造成损伤。慢速冷冻对内皮细胞破坏小 ,对血管平滑肌的收缩和内皮依赖性舒张的损害小。

Objective: To estimate the influence of the cooling-rate on the endothelial viability and function of the artery of large caliber. Methods: Thoracic aorta harvested from 16 piglets, each aorta divided into 3 segments. One is the control, the other two were frozen with the cooling-rate of -1℃/min and -5℃/min to -40℃. The measurement after thawing includes endothelial mortality, vascular contraction caused by noradrenaline (NA) the endothelial-dependent relaxation caused by acetylcholine (Ach). Results: The epithelial viability of 2 frozen groups was significantly lower than controlled group (P<0.01). And the endothelial viability of -5℃/min group was significantly lower than -1℃/min group (P<0.01). The value of contraction caused by NA of 2 frozen groups was significantly lower than controlled group (P<0.01). And the contraction of -5℃/min group was significantly lower than that of -1℃/min group (P<0.01). There was no difference about the values of relaxation caused by Ach among 2 frozen groups and the controlled group (P>0.05). But there was significant difference about the percentage of the relaxation among 2 frozen groups and the controlled group (P<0.01). There was negative correlation between the endothelial mortality and endothelial-dependent relaxation (P<0.05). Conclusion: Cryopreservation caused structural and functional damage to aorta. Slow cooling-rate caused lower epithelial mortality, less damage to smooth muscular contraction and the endothelial-dependent relaxation than fast cooling-rate.