Abstract
Cytokine levels of interleukin-lα (IL-lα), interleukin-1β (IL-1β), interleukin-3 (IL-3), interleukin-6 (IL-6), erythropoietin (EPO) and tumor necrosis factorα (TNFα) in bone marrow of Wistar rat were measured with immunofluorescent assay. The levels of IL-lα, IL-1β, IL-3, IL-6 and EPO were high in young (4 weeks old), and gradually decreased thereafter. In contrast, TNFα level in bone marrow was low by 18 weeks old and high at 26 and 52 weeks old. These results indicated that age-associated changes of bone marrow cell composition in rat are well correlated with the levels of cytokine related to bone marrow cell differentiation.