The Relationship Among Platelet Age, Volume and Electrophoretic Mobility

Abstract

The platelet carries a net negative charge and its change may be an important factor in platelet adhesion and aggregation. Platelet age and volume are also believed to be important factors in its functions. Six male rabbits were injected with 50 μCi of 75Selenomethionine intravenously and EDTA-blood was drawn 3 days after. Platelets were washed 3 times and suspended in 3 mM triethanolamine acetate carrier buffer. Platelet electrophoresis was performed using with a Continuous Free-Flow Electrophoresis VAP-5 (Bender & Hobein, Munich). Electrode buffer used was 100 mM triethanolamine acetate buffer pH 7.4 and electrophoresis was performed at 17.5°C, 1250V and 80mA. Approximately 5×108 platelets were electrophoresed per hour into 90 fractions. The fraction #1 is the anode side and #90 cathode side. Platelets in each fraction obtained as a suspension in the buffer were studied for platelet count and volume determinations using with a Coulter Counter ZbI and a Channelyzer C-1000. The radioactivity was measured by a well-type scintilation counter. Platelets were separated well making a single peak at the 27±3.4 fraction. The radioactivity of platelet increased as the fraction number increased but platelet in bilateral side fractions was too small in number and determination of the radioactivity was difficult and the peak radioactivity was at the measurable extreme right fraction (68±3.8). The largest platelet volume also appeared at the measurable extreme right (cathode side) fraction. In conclusion, Continuous Free-Flow Electrophoresis separated platelets well by the difference of cell surface potentials. 75Selenomethionine labeled platelets which have been thought to be young seem to have low electrophoretic mobility and relatively large volume.