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Objective To investigate the feasibility of deep cryopreservation of fresh platelets after riboflavin photochemical-mediated virus inactivation. Methods A total of 24 samples of platelets were collected from O-type healthy free blood donors in our general hospital, with each sample of 200 mL. The platelet samples were subsequently divided into 4 groups: fresh platelets control group (group A), virus inactivated control group (group B), fresh platelet cryopreservation group (group C, stored at -80 ℃) and cryopreservation of virus inactivated platelets group (group D, riboflavin photochemical-mediated virus inactivation and then stored at -80 ℃). In group B and D, the platelets were treated with riboflavin photochemistry (150 μmol/L riboflavin solution and 1.5 J/cm2 UVB radiation). The next day after cryopreservation was defined as day 1, and the ultrastructural alterations of platelets were observed with scanning electron microscopy. The quantity, quality, functional and metabolism parameters of platelets were determined on days 1, 3, 5 and 7, respectively. Platelet count (PLT) and mean platelet volume (MPV) were measured using an automatic blood routine counter; the hypotonic shock response (HSR) of platelets was observed with colorimetry; Annexin V-FITC and CD62p-PE kits and flow cytometry were adopted to examine cell apoptosis and activation; thromboelastogram test (TEG) was conducted to detect the functional changes of platelets for the maximum amplitude (MA) value; and the changes of glucose and lactate content were also tested by rate methods. Results As compared with group A, the platelets in groups B, C and D were in irregular shape with more parapodia stretched out, which represented an obvious activated state. All groups showed augmented MPV with time prolonging, and the MPV ualues in groups C and D were significant greater than those of groups A and B (P < 0.01). The HSR of each group was decreased gradually with elapse of preservation time, with groups C and D presenting more obvious reduction than groups A and B (P < 0.01). The positive rates of CD62p and Annexin V in all groups were elevated over time, and the apoptosis and activation were most notable in group D. The MA value had no significant differences among groups. In addition, the glucose content was declined significantly during preservation, with groups A and B more obvious, while the alteration of lactate was opposite. We found that the morphology and quality of platelets were affected by cryopreservation, and the effect was significantly greater than that caused by virus inactivation. However, its effect on platelet function and metabolism was not distinct. Conclusion It is feasible for deep cryopreservation of platelets after riboflavin/UVB photochemical-mediated virus inactivation |
