Changes in HS mouse erythrocyte mass and area with respect to donor age

Interferometric photographs of blood smears from heterogeneous stock (HS) mice were analyzed for age-related changes in erythrocyte mass using quantitative cytophotometry. Blood smears were obtained from 96 mice (half male/half female) sacrificed at 172, 272, 374, 482, 581, and 664 days of age as part of a larger biomarkers of aging study. Blood smears from each animal were photographed with a Leitz Mach-Zehnder interferometer, and the erythrocyte images on these negatives were measured for dry mass using a Vickers M85a microdensitometer. Cell area measurements were made from a video-microscope image traced with a computer digitizer. Results indicated that animals from middle-age groups (272, 374, and 482 days) have higher red blood cell mass than animals at either young (172 days) or older (581 and 664 days) age groups. Mass changes with respect to age followed similar trends when data were further examined with regard to sex of the animals. Erythrocyte area measurements showed a general age-related decrease in cell size.