GM-CSF stimulates mouse macrophages and causes inflammatory effects in vitro

Abstract

Macrophages are involved at an early stage of the inflammatory reaction and have an important role in wound healing. Granulocyte-macrophage colony stimulating factor (GM-CSF) stimulates the proliferation and differentiation of macrophages. We investigated the secretion of tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4) from mouse macrophages (RAW264.7) activated by GM-CSF. RAW264.7 cells were cultured on titanium (Ti) discs. Secretion of TNF-α and IL-4 was evaluated using enzyme-linked immunosorbent assay (ELISA) at 24 h and 48 h. Cell morphologies were observed using SEM, and cell viability was accessed by an MTT assay. GM-CSF caused rough and irregular surface morphology on the macrophages and resulted in a significant difference in cell viability after 48 h (p<0.05). TNF-α secretion significantly decreased after 48 h without GM-CSF compared with that at 24 h (p<0.05). GM-CSF significantly increased the secretion of TNF-α after 24 h and 48 h (p<0.05). IL-4 secretion was significantly different with or without GM-CSF stimulation at 24 h and 48 h (p<0.05). There was a significant increase in IL-4 secretion 24 h and 48 h after GM-CSF stimulation (p<0.05). These results suggest that macrophage stimulated GM-CSF may promote secretion of anti-inflammatory and pro-inflamma-tory cytokines on Ti.