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

The influence of age on platelet lipid peroxide (LPO), platelet membrane fl uidity 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 signifi cantly higher (p<0.05) in the platelets of upper age groups than in those o f 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-hexatr iene (DPH) fluorescence polarization, was significantly reduced with age. T he composition of fatty acid demonstrated an age-related elevation (p<0.05) in the unsaturation index. The rises in the LPO levels revealed a signific antly positive correlation with DPH-polarization (r=0.73, p<0.0001). Thus o ur results suggested that the age-related deterioration of platelet membran e fluidity, despite a significant elevation in the unsaturation index, was due to the age-related higher basal, levels of LPO in platelets.