Association of age-related decrease in platelet membrane fluidity with platelet lipid peroxide.

The influence of age on platelet lipid peroxide (LPO), platelet membrane fluidity and the composition of fatty acid was investigated in female Wistar rats widely ranging in age from 14 to 720 days old. LPO levels were significantly higher (p<0.05) in the platelets of upper age groups than in those of lower age groups, showing a significantly positive correlation with age (r=0.84, p<0.0001). Membrane fluidity, assessed by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence polarization, was significantly reduced with age. The composition of fatty acid demonstrated an age-related elevation (p<0.05) in the unsaturation index. The rises in the LPO levels revealed a significantly positive correlation with DPH-polarization (r=0.73, p<0.0001). Thus our results suggested that the age-related deterioration of platelet membrane fluidity, despite a significant elevation in the unsaturation index, was due to the age-related higher basal levels of LPO in platelets.