Modulation of Granulocyte Colony-stimulating Factor Effects on Haematopoiesis by Lipopolysaccharide and Pentoxifylline in CF<SUB>1</SUB> Mice

Abstract

Granulocyte colony‐stimulating factor (G‐CSF) at 250 μg kg−1 per day stimulates white blood cell (WBC) proliferation in mice with significant increases from 72–120 h. Lipopolysaccharide (LPS) treatment as a single dose (5 mg kg−1) at 72 h abolishes the induced WBC proliferation of G‐CSF from 72–120 h. Pentoxifylline at 50 mg kg−1 per day does not interfere with the proliferation effect of G‐CSF on white blood cells; the drug did not protect against the effects of LPS in abolishing WBC proliferation. LPS alone or with G‐CSF treatment at 250 μg kg−1 per day in‐vivo significantly elevated tumour necrosis factor‐α (TNF‐α) levels after 90 min. These levels were significantly reduced by pentoxifylline at 50 or 100 mg kg−1 per day after 72 h, but not when administered 30 min before LPS treatment. Factors other than TNF‐α levels appear to be involved in the regulation of haematopoiesis by G‐CSF.