中文摘要：

冷冻干燥法是使血小板能够长期保存的一种理想方法。冻结过程对血小板的冻干保存至关重要。采用梯度降温、搁板预冷、液氮冻结等三种冻结方式，研究了冻结速率对血小板冷冻干燥保存恢复率的影响。实验结果表明用搁板预冷的方式冻结并干燥的血小板复水后的恢复率最高，达到（93．0±5．2）％，此时的冻结速度约为10℃／min。扫描电镜照片显示冻干复水后的血小板保持了完整的细胞结构，但与新鲜血小板相比略呈球形。冻干复水后的血小板对1U／ml凝血酶的最大聚集率接近于新鲜血小板，但聚集速度比新鲜血小板慢。

英文摘要：

Freeze-drying is an ideal alternative for long-term preservation of platelets in blood banks. Freezing process is important for recovery of freeze-dried of platelets. In this study, the effect of freezing rates on the recovery of freeze-dried human platelets in the presence of 1% bovine serum albumin and 20% trehalose were investigated. Three cooling methods were employed, including gradient cooling, shelf cooling and plunging the sample into liquid nitrogen. The results show that shelf cooling was the best way to cool the sample, the highest recovery of freeze-dried and rehydrated platelets reached （93.0±5.2）%, the optimum rate of freezing is about 10℃/ min. Furthermore, SEM was employed to investigate the morphology of freeze-dried and rehydrated platelets but more rounder compared with fresh platelets. The maximum aggregation rate of these platelets to thrombin （1 U/ml） was close to that of fresh platelets, but aggregation speed was more slowly than the fresh ones.