[Macrophage colony-stimulating factor production and c-fms expression in cultured rat aortic vascular smooth muscle...

The resulats of this study are as follows. (1) As measured by a bioassay, a macrophage colony-stimulating activity was detected in the serum-free conditioned medium of rat aortic vascular smooth muscle cells (VSMCs), which could be subdued by the addition of specific anti macrophage colony-stimulating factor (MCSF) antibody. (2) The presence of MCSF receptor was confirmed by immunocytochemistry using a specific anti c-Fms antibody. (3) The presence of mRNAs for MCSF and c-fms (which encoded MCSF receptor) was determined by Northern blot analysis. Their expressions were detectable in quiescent VSMCs and markedly increased after addition of serum. These data demonstrated for the first time the production of MCSF and the presence of MCSF receptor in cultured rat VSMCs. It is suggested that MCSF might modulate VSMCs functions via both autocrine and paracrine mechanisms. Rat VSMCs appear to be a suitable cell model for studying the cell proliferation effect of MCSF.