An animal model to study erythrocyte senescence with a narrow time window of erythrocyte production

Using the method of inducing spherocytic anemia in the rabbit with antibody serum, we have developed an animal model in which red blood cells (RBCs) can nearly grow synchronously. With this model, we determined that the surface charge density on the RBC membrane decreased with cell aging. The change was not linear, being much more profound in the latter half of RBC life span. There was a positive correlation between the mean RBC density and its “age” ( $r=0.847$ , $p<0.01$ ). However, the density distribution of the RBCs at the same “age” showed a broad range, and the density values for RBC groups with different ages showed considerable overlap. This indicates that the density gradient technique can be used to separate RBC population into fractions with different mean ages, but has a low resolving power for obtaining individual RBCs of a given “age”.