Aim: The aim of this study was to find a correlation between the rheological properties and morphological changes of Red Blood Cells (RBCs) during the oxidative injury induced by 2,2-azo-bis (2-amidinopropane) dihydrochloride (AAPH) in blood donors with borderline level of hyperlipidemia compared with a control group.

Methods: Haemolysis was evaluated spectrophotometrically. The RBCs deformability index (elasticity) was determined by creep tests performed on a Dynamic Stress Rheometer (DSR-500) and morphological changes were observed with an DSM 940 scanning electron microscope.

Results: The total elasticity values suggest a RBCs deformability reduction in the borderline group compare to control group causing an enhancement of the solid-like behaviour of RBCs suspensions. The deformability reduction is associated to a decreased globular resistance and acanthocytes formation in a AAPH exposure time-dependent manner. The increased viscosity observed in the control group is a typical trend of suspensions of materials in which the suspended particles have a greater rigidity, while in the borderline group probably rouleaux and RBCs lysis induce a compensatory effect on viscoelastic behavior.

Conclusions: RBCs shown shape changes under oxidative injury and can be permanently altered by excessive exposure affecting deformability in a time dependent-manner rather than aggregability in subjects with borderline level of hyperlipidemia.