RESUMO
The purpose of this study was to evaluate the in vivo viability of human platelets cryopreserved at -80 degrees C by using SCID mouse model and flow cytometry. The fresh human platelets were frozen with 5% DMSO at -80 degrees C for 10 days, thawed, and centrifuged for concentration. A 100 ml aliquot of concentrated platelets was injected into the SCID mouse tail vein by using a 1 ml insulin-syringe fitted with a 29-gauge ultra-fine needle. The whole blood was collected into heparinized capillary tube at 0.5, 2, 4, 6, 12, and 24 hours after infusion via a tail vein and was labelled with CD61-PE. Then the human platelets in mouse whole blood were detected by flow cytometry. The 30 minute time point was used as 100% to calculate the survival time of human platelets. The results showed that the survival time of cryopreserved human platelets were more significantly decreased than that of fresh platelets in SCID mice. Survival rates at 4 hours after transfusion of fresh platelets and cryopreserved platelets in SCID mice were 79.5% +/- 9.1% (n = 8) and 40.6% +/- 6.6% (n = 8) respectively, and a T(1/2) estimated were 7 hours for fresh platelets, but 2.5 hours for the cryopreserved. In conclusion, platelets survival time in SCID mice was shortened after frozen with DMSO at -80 degrees C.