Effect of Macrophages on Fibroblast DNA Synthesis and Proliferation

Mouse peritoneal macrophages incubated with mouse 3T3 fibroblasts modulate DNA synthesis by the fibroblasts as measured by 125IUDR incorporation into DNA. The factor responsible for this activity is soluble and inhibits fibroblast DNA synthesis when present in high concentrations, whereas stimulation was observed at lower concentrations. Similar findings were observed when soluble fractions from human peripheral monocytes were incubated with primary human skin fibroblasts. In addition to increased DNA synthesis, there was a significant increase in human fibroblast proliferation as measured by direct cell counting. These findings support the hypothesis that macrophages play a regulatory role in wound healing through their capacity for positive and negative regulation of fibroblast DNA synthesis and proliferation.