Effect of granulocyte-macrophage colony-stimulating factor on treatment of acute osteomyelitis - An experimental investigation in rats

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that affects the various developmental steps of hematopoietic cells and enhances the phagocytic activity of these cells. The effect of GM-CSF on acute osteomyelitis, developed in rats, was investigated. For this purpose, osteomyelitis was firstly developed through the direct inoculation of Staphylococcus aureus into rat tibial metaphysis. Twenty-four rats in which diagnosis of osteomyelitis was histopathologically established were divided into two groups. Antibiotic only was given to the first group, and antibiotic as well as CM-CSF to the second roup. Rats were followed up for 3 months with plain radiographs and scintigraphic methods using (67)Gacitrate. Material obtained from the rats that had been killed at the end of the 3rd month were histopathologicalIy investigated. One rat in the first group died. In another rat, chronic osteomyelitis developed and fracture was observed. In 12 rats of the second group, physical examination, plain radiographs, and histopathologic findings were normal. In scintigraphic studies with Ga-67-citrate, when the pre- and posttreatment values of the same groups were evaluated by the Mann-Whitney U-test, the mean values at 48 h after treatment were found to be significant (P < 0.05), indicating a decrease in the 2nd group (experimental group). In conclusion, the antibiotics were effective in the elimination of infection only together with neutrophils. In this manner, infections may be eliminated by strengthening the host's defense mechanism as well as by administering antibiotics. We believe that an adequate number of long-term studies will shed light on this issue. Besides we consider that this factor will be more important in the study of chronic osteomyelitis.