Abstract: Objective To investigate the expression changes and significance of pri-miR-223 associated with prolonged storage time during platelet storage. Methods Blood cell analyzer was used to detect platelet mass at different preservation times (1, 3, 5 days), and metabolomic analysis was performed. The Droplet Digital PCR (ddPCR) method was developed to evaluate its sensitivity and reproducibility. The ddPCR was used to detect the expression level of pri-miR-223 in platelet at different storage times, and to analyze the effect and significance of PRI-Mir-223 on platelet storage lesion (PSL). Results There were no significant differences in platelet count (PLT), platelet-large cell ratio (P-LCR), mean platelet volume (MPV) and platelet distribution width (PDW) among different preservation times with extended times (P>0.05). A total of 955 metabolites were identified by metabolomics, of which 54 metabolites were up-regulated and 6 metabolites were down-regulated. The developed ddPCR method showed good specificity and high sensitivity. The standard curve showed good linear correlation (Y=0.973 6 X+0.083 2). The R² value was 0.9984, and linear dynamic range sensitivity was 3.3×10⁰~1.9×10⁵ copies /μL. The ddPCR results showed that the expression level of pri-miR-223 on day 3 and 5 was significantly lower than that on day 1. Conclusion With extended storage time, PLT, P-LCR, MPV, and PDW were not affected, and some metabolites were changed at the end of the storage period, and ddPCR analysis showed the expression level of pri-miR-223 decreased, which may be related with the regulation of pri-miR-223 expression.

Key words: Platelet storage, Metabolomics, Digital PCR, pri-miR-223