FIG. 8.

Induction of G-CSF and GM-CSF mRNA expression in cocultures of bacterially exposed and unexposed osteoblasts. Mouse osteoblasts were used to seed the upper and lower chambers of Transwell plates. Osteoblasts in the lower chamber were left unexposed (lane 0) or exposed to S. aureus or Salmonella at the indicated ratios (250:1 and 75:1 or 10:1 and 3:1 bacterium-to-osteoblast ratios, respectively) for 45 min, and then extracellular bacteria were removed. Following exposure of osteoblasts in the lower chamber, upper chambers containing unexposed osteoblasts were positioned in the Transwell plates. RNA was isolated from the upper and lower chambers 12 h following exposure to bacteria, and a semiquantitative RT-PCR was performed for each mRNA species. Results are presented as amplified products electrophoresed on ethidium bromide-stained agarose gels. RT-PCR amplification of the G3PDH housekeeping gene was performed to ensure that similar amounts of input RNA and similar RT efficiencies were being compared. These studies were performed twice with similar results.