Electrokinetic properties of human cryopreserved platelets

SUMMARY. A method for the cryopreservation of human platelets with glycerol/glucose is described which was a simplified modification of the method of Dayian and Pert (1979). The effect of cryoinjury of the platelet surface membrane was investigated by studying the surface electrokinetic properties of the platelet. A significant increase in platelet electrophoretic mobility was found after cryopreservation. The fresh platelets had a mean electrophoretic mobility of 1.04 ± 0.05 μm s^-1 V^-1 cm^-1 and cryopreserved platelets 1.18 ± 0.05 μm s^-1 V^-1 cm^-1, P < 0.05. However, the total platelet sialic acid of fresh platelets was 62.5 ± 5.6 nmol 10^-9 platelets compared to 47.2 ± 4.6 nmol 10^-9 platelets after cryopreservation, P < 0.001. Similarly, the neuraminidase-labile sialic acid was 26.4 ± 4.3 nmol 10^-9 platelets for fresh platelets and 17.6 ± 4.0 nmol 10^-9 platelets after cryopreservation, P < 0.001.
Using polyacrylamide gel electrophoresis with Western blotting, we showed a reduction in the platelet glycoprotein Gp Ib after cryopreservation, this was confirmed by using crossed immunoelectrophoresis. Electron microscopy revealed a significant change in platelet morphology after the cryopreservation procedure with disruption of the platelet membrane and also platelet shape change. These features may explain the changes in platelet electrokinetic properties.