Impact of platelets in vitro function on different time after acquisition for cryopreservation

Objective To explore impact of platelets in vitro function on different time after acquisition for cryopreservation. Methods From December 2011 to December 2013, a total of 180 bags platelets which were collected in Dongying Central Blood Station were included into this study. All the platelets were divided into two groups by computer randomly. Within 12 h frozen group (n=90) included 90 bags platelets, which were frozen stored within 12 h after collection. After 72 h frozen group (n=90) also included 90 bags platelets, which were frozen stored before general preservation for 72 h. Melting and collection methods of platelets in two groups were the same, and there were no statistically significant in platelet counts or other baseline data before cryopreservation in two groups (P>0.05). After one year cryopreservation, platelets were melted and 10 mL platelets were collected for in vitro function tests. Platelets in vitro function tests included CD62P expression rate, adhesion function, hypotonic shock response (HRS) and aggregation function. Above indexes in two groups were compared. Results After one year cryopreservation, the platelet counts, CD62P expression rate, adhesion function and HRS value in two groups were (2.5±0.4)×109/L vs (2.5±0.4)×109/L, (20.2±4.6)% vs (19.9±4.3)%, (71.3±4.7)% vs (70.8±4.5)%, (43.5±6.7)% vs (52.5±5.5)%, and (53.4±11.1)% vs (52.8±10.5)%, respectively. There were no statistical differences between two groups in each index (u=0.00, 0.05, 0.08, 0.04, 1.04; P>0.05). Max aggregation rate of platelets in two groups after adding with collagen, ristocetin, thrombin and arachidonic acid were (35.6±12.1)% vs (33.4±14.0)%, (23.5±11.2)% vs (21.5±12.1)%, (47.0±8.8)% vs (46.8±7.9)%, and (40.2±26.3)% vs (38.4±23.3)%, respectively. There were no statistical differences in max aggregation rate between two groups (u=0.12, 0.12, 0.02, 0.05; P>0.05). Conclusions The method that platelets frozen stored after 72 h general preservation could not only meet the clinical needs of the fresh liquid platelets, but also protect clinical emergency blood needs. Key words: Blood platelets; Cryopreservation; Blood preservation