预冻技术参数对血小板冻干保存的影响

本研究采用正交设计方案探讨冻结速率、退火速率、退火温度和退火持续时间4个预冻条件参数对血小板冻干保存的影响．冻干血小板再水化后的数值恢复率、细胞形态和结构、血小板活化和聚集力等指标分别用血细胞计数计、扫描电子显微镜、3色流式细胞仪及对凝血酶的聚集反应进行检测并综合评价．结果显示：在不同的预冻条件组合方式下，冻干血小板的数值恢复率在（91．3％-53．5）％范围内；实验各组血小板冻干制品的冰晶大小和形状有所不同；冻干再水化血小板的活化标记物PAC-1和CD62p的表达和分布与新鲜血小板较为接近，其中PAC-1表达率均维持在较低水平（0．03％-0．22％），而各组样本CD62p的表达水平存在差异．实验中根据血小板数值恢复率得到预冻条件的最佳理论组合是A2B1C1D3，即将血小板悬液先以20℃／min的速率冻结至-40℃维持2小时。再以1．5℃／min对搁板升温至-30℃后维持0．5小时，最后进入冻干程序直至结束。结论：冻结速率、退火速率、退火温度和退火持续时间对冻千血小板的数值恢复率均有作用，预冻条件参数的不同组合方式影响血小板冻干保存效果．

Effect of prefreezing parameters on human platelet cryopreservation

This study was aimed to investigate the effect of prefreezing parameters such as freezing rate, annealing, rate, annealing temperature, holding time in annealing before lyophilization on lyophilized platelets by orthogonal tests. The recovery rate, the morphological and ultrastructural changes, the activation and aggregation of lyophilized platelet after rehydratation were detected by cytometer, scan electron microscopy, flow cytometry and aggregation reaction on thrombin, respectively, and complex evaluation was carried out. The results showed that the recovery rate of lyophilized platelets was 91% - 53.5% at different conditions of lyophilization, the size and shape of ice crystals in lyophilized platelets of different test groups were not similar, the expression and distribution of platelet activation markers (PAC-1 and CD62p) after rehydration were relatively similar to fresh platelets, expression rate of PAC-1 was lower (0.03% - 0.22%), meanwhile there were differences of CD62p expression levels between different groups. The optimal theoretic composition of prefreezing conditions obtained on basis of platelet recovery rate was A(2)B(1)C(1)D(3), i.e, first, suspensions of platelets on the program control cooling apparatus were lyophlized with a rate of 20 degrees C/min and maintained at -40 degrees C for 2 hours, then the annealing was conducted at -30 degrees C for 0.5 hours with a heating rate of 1.5 degrees C/min; finally, the freeze-drying program was carried out to the end. It is concluded that the freezing rate, annealing rate, annealing temperature and holding time of annealing all impact on the recovery of lyophilized platelets. The preservation qualities of lyophilized platelets were affected by the various combinations of prefreezing parameters.