ABSTRACT
Objective: To observe the outcomes of different cooling rates in the cryopreservation of platelets, so as to screen the best cooling rate for cyropreservation of platelets. Methods: Platelet concentrate was cooled down with the new cryopreserving solution at various cooling rates(1, 10, 20°C/min) and was kept at ∼80°C for one week. Then platelets were thawed to check platelet count, adrenaline induced aggregation, and expression of CD41, CD42b and CD62p; the results were compared with those of the non-programmed cooling group and fresh platelets. Results: The platelet counts of cryopreserved groups were lower than that of fresh platelet concentrate (P<0.05 or P<0.01). There were no differences in adrenaline induced aggregation between 10°C/min group, 1 °C/min group, and non-programmed cooling group; and the aggregation of the former 3 groups was lower than that of 1 °C/min group(P<0.01) and higher than that of 20 °C/min group (P<0.05). The CD42b expression in 10 °C/min group was higher than in other groups (P<0.05) and lower than in fresh platelet concentrate. The CD62p expression in 1 °C/min group, 20 °C/min group, none programme cooling group was higher than in fresh platelet concentrate (P<0.05). The CD62p ex: ression in 10 °C/min group was higher than other 3 groups (P<0.05) and lower than in fresh platelet concentrate, with no statistical significance. Conclusion. Cooling rate has great impact on the quality of cryopreservted platelets. Compared with 1 °C/min and 20 °C/min, 10 °C/min is the optimal cooling rate with the new cryopreservation solution in this study.