Decreased adhesion of oxidized LDL-stimulated platelets caused by cytochalasin D

The adhesion of human blood platelets is studied with an in vitro model using reflection contrast microscopy and an image analysis system. The adhesive feature is promoted by oxidatively modified low density lipoprotein, which also induces functional morphological changes of platelets. However, when washed platelets are pretreated with 0.05 mM cytochalasin D, oxidized low density lipoprotein (100 micrograms/ml) causes a slower increase of the adhesion area (11.6 microns 2/min) compared to untreated platelets (15.7 microns 2/min) or platelets treated by oxidized low density lipoprotein alone (20.5 microns 2/min, P < 0.01). These results are supported by light transmission analysis and by transmission electron microscopy. Our experiments suggest that cytochalasin D inhibits the change of platelets in shape induced by oxidized low density lipoprotein, hinders the adhesion, but does not prevent the adhesion entirely.