Modifications of erythrocyte membrane fluidity of in vivo functionally aged human erythrocytes.

The process of red blood cell senescence in the blood stream results in many changes in their physical and biochemical properties. In this work we have studied the physico-chemical state of erythrocyte membranes prepared from 5 subpopulations of erythrocytes of different age by using the fluorescence technique. Membrane fluidity has been evaluated by the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and a further study of the fluorescence decay of this probe has been performed by multifrequency phase and modulation fluorometry. DPH fluorescence polarization is significantly increased in the membranes prepared from the youngest fraction of erythrocytes, indicating a decreased fluidity without any significant change in DPH fluorescence decay.