Inhibition of cyclooxygenase 2 in mice increases production of g-csf and induces radioprotection.

Meloxicam, a selective inhibitor of cyclooxygenase 2, was tested to determine its ability to modulate hematopoiesis and to influence survival of mid-lethally gamma-irradiated mice. A single dose of meloxicam (20 mg/kg) administered to mice intraperitoneally 1 h before irradiation was shown to enhance serum levels of granulocyte colony-stimulating factor (G-CSF) during the first 24 h after irradiation, to elevate numbers of granulocytic precursor cells in bone marrow and granulocyte counts in peripheral blood on day 10 after irradiation, and to increase 30-day survival of these mice. The results provide new evidence for the protective ability of meloxicam administration to mice irradiated with mid-lethal doses and contribute to the understanding of the mechanisms of this meloxicam action by drawing attention to the possible role of increased endogenous G-CSF production.