ELECTROKINETIC PROPERTIES OF HUMAN CRYOPRESERVED PLATELETS

A method for the cryopreservation of human platelets with glycerol/glu cose is described which was a simplified modification of the method of Dayian and Pert (1979). The effect of cryoinjury of the platelet surf ace membrane was investigated by studying the surface electrokinetic p roperties of the platelet. A significant increase in platelet electrop horetic mobility was found after cryopreservation. The fresh platelets had a mean electrophoretic mobility of 1.04 +/- 0.05 mu m s(-1) V-1 c m(-1) and cryopreserved platelets 1.18 +/- 0.05 mu m 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 1 0(-9) platelets after cryopreservation, P < 0.001. Similarly, the neur aminidase-labile sialic acid was 26.4 +/- 4.3 nmol 10(-9) platelets fo r fresh platelets and 17.6 +/- 4.0 nmol 10(-9) platelets after cryopre servation, P < 0.001. Using polyacrylamide gel electrophoresis with We stern blotting, we showed a reduction in the platelet glycoprotein Gp Ib after cryopreservation, this was confirmed by using crossed immunoe lectrophoresis. Electron microscopy revealed a significant change in p latelet morphology after the cryopreservation procedure with disruptio n of the platelet membrane and also platelet shape change. These featu res may explain the changes in platelet electrokinetic properties.