Journal of Evolutionary Biochemistry and Physiology · Jun 2026
Blood Rheological Properties in Rats of Different Ages
By Николаевна ШВ, Gorshkova OP
Abstract To ensure adequate tissue perfusion, along with a properly functioning endothelium that enables vasodilation, the rheological properties of blood, such as hematocrit, blood viscosity, erythrocyte (RBC) deformability and aggregation, are important components of the circulatory system. Experiments on Sprague–Dawley rats aged 4, 18, and 23 months have shown that with age, hematocrit decreases, plasma and blood viscosity increase, and the degree of RBC aggregation rises. The RBC deformability index also significantly increases, indicating a decline in cell deformability. Along with age-related changes in blood rheological properties, an increase in desquamated endothelial cell count was observed in the blood plasma, indicating endothelial dysfunction. Overall, such changes lead to impaired microcirculation. The age-related changes in blood rheological parameters, as recorded in our study, are consistent with the results of cerebral cortex perfusion using Doppler ultrasonography and indicate a deterioration in microcirculation. Rheological parameters, such as blood viscosity, the degree of RBC aggregation, and their deformability index, in rats change as early as 18 months of age and can serve as markers of age-related changes in healthy animals.