Old Mice: Marrow Response to Bleeding or Endotoxin 1

Abstract

Abstract

Peripheral blood hemoglobin, white cell, and lymphocyte levels decreased significantly with age in healthy female B6D2F₁ mice. However, these old mice maintained their hemoglobin levels in the face of chronic blood loss as well as did young mice by releasing younger than normal RBC into the peripheral circulation. In addition, before and after bleeding, the old mice had at least as many marrow and spleen CFU-S and CFU-C as did young mice. Old mice given endotoxin responded with greater elevations of peripheral blood lymphocytes and PMN than did young animals; the response of marrow CFU-S, CFU-C, and T-cell precursors to endotoxin was not impaired in old mice. Indirect evidence suggests that acute bleeding may increase the number of spleen CFU-S and T-cell precursors in old animals.