The effect of glycerol on aggregation and ultrastructure of human platelets

Cryopreservation of platelets depends on the use of cryoprotectants to reduce freezing damage. However, the cryoprotectants may in themselves be harmful, and it is important to determine the amount of damage caused by these compounds. Platelets were incubated at 37 °C in plasma containing 0, 0.5 and 1.0 mol/liter glycerol. The aggregation response to 10 and 5 μmol/liter ADP was determined after 2, 15, 30, 60, and 120 min of incubation. Samples were prepared for electron microscopy after 30 min at 37 °C. Glycerol at a concentration of 0.5 mol/liter had no effect on the extent of aggregation, whereas 1.0 mol/liter glycerol caused a progressive decline in the response. However, platelet ultrastructure appeared to be undisturbed by 1.0 mol/liter glycerol. The results demonstrated a lack of toxicity of 0.5 mol/liter glycerol and support the use of glycerol at concentrations less than 1.0 mol/liter for cryopreservation.