Electrophoretic mobility of platelets and its physiological significance

Abstract

Increasing attention has been paid to the surface electrical charge of platelets in relation to their functions. However there are several criticisms in methodological respects. In the present investigation the effect of neuraminidase on platelets was examined utilizing newly developed instruments of electrophoresis. These are Free-Flow Electrophoresis model Vap-5 (Bender and Hobein, West Germany) and Laser-Zee System 3000 (Pen-Kem Inc., U. S. A.). Rabbits were catheterized in the carotid artery and blood was obtained with EDTA as an anticoagulant. Platelet rich plasma was washed twice with Tris-HCl buffered saline and platelets were finally suspended in pH 5.3 acetate buffered saline. Washed platelets added with various concentrations of neuraminidase or control saline were incubated at 37°C for an hour. After incubation platelets were washed and suspended in 3mM triethanolamine acetate or 0.001M HEPES-NaOH, 0.15M NaCl buffer for electrophoresis with Free-Flow or Laser-Zee system respectively.Results: Electrophoretic distribution of neuraminidase-treated platelets was shifted to the cathode side as compared with the control. The magnitude in shift of electrophoretic distribution depended upon neuraminidase concentration and there was a correlation between them (Fig. 1A, B). Relation between electrophoretic mobility and volume of platelets before and after the neuraminidase treatment was shown in Fig. 2A, B and 3. In general larger platelets were distributed in the anode side and smallers in the cathode side. With lower concentration of neuraminidase treatment this trend as shown by a regression line got greater. This result represents that the sensitivity of platelets to neuraminidase is various in accordance with the platelet volume and smaller platelets are more sensitive to neuraminidase. The platelet sensitivity to neuraminidase may have some role in platelet turn-over as smaller platelets have been believed as older ones.