Characterization of age-associated changes in peripheral organ and brain region weights in C57BL/6 mice.

In order to further understand age-related physiological changes and to have in depth reference values for C57BL/6 mice, we undertook a study to assess the effects of aging on peripheral organ weights, and brain region weights in wild type C57BL/6 male mice. Peripheral organs, body and brain region weights were collected from young (3-4 months), mid (12 months), old (23-28 months) and very old (>30 months) mice. Significant increases are observed with aging in body, liver, heart, kidney and spleen organ weights. A decrease in organ weight is observed with aging in liver and kidney only in the very old mice. In contrast, testes weight decreases with age. Within the brain, hippocampi, striata and olfactory bulbs weight decreases with age. These data further our knowledge of the anatomical and biological changes that occur with aging and provide reference values for physiological-based pharmacokinetic studies in C57BL/6 mice.