[Discharge and Contents of Exosome from Leukocyte-Reduced Apheresis Platelet Stored for Different Storage Time].

Objective: To explore the effect of storage time on discharge and content of exosome from leukocyte-reduced apheresis platelets (LRA-Plt).

Methods: Exosome (EXO) from LRA-Plt were acquired by ExoQuick, and its' morphology, immunological marker and particle size distribution were detected by transmission electron microscopy (TEM), Western blotting and dynamic light scattering (DLS), respectively. The changes in particle size distribution of EXO from LRA-Plt with different storage time were detected by DLS. The changes in content of protein and RNA of EXO from LRA-Plt with different storage time were detected by Nanodrop® ND-2000.

Results: EXO from LRA-Plt was acquired successfully, which was characterized by cup-like shape, CD63/TSG101 enriched and Calnexin negative, and the particle size of which ranged from 30 to 200 nm. At early stored stage (stored for 1 day and 2 days), particle size of EXO from LRA-Plt was small and ranges from 30 to 40 nm. Meanwhile, the contents of protein and RNA were low. The particle size distribution, contents of protein and RNA of EXO from LRA-Plt were not significanty different ammg groups (P＞0.05). At middle-late stored stage (stored for 3, 4 and 5 days), the particle size of EXO from LRA-Plt was larger than that of early stored stage, which ranges was from 130 to 200 nm. Meanwhile, the contents of protein and RNA were higher than those of early stored stage. Particle size distribution, contents of protein and RNA of EXO from LRA-Plt stored for middle-late stage were significant higher than those of early stored stage (P＜0.05).

Conclusion: Morphology of EXO from LRA-Plt stored for middle-late stage was different from that stored for early stored stage. Moreover, the particle size distribution, contents of protein and RNA of EXO from LRA-Plt stored for middle-late stage were higher than those of early stored stage. A large amount of protein and RNA contained in EXO from LRA-Plt may participate in the multiple functions caused by platelet transfusion.