Abstract：The occurrence of inflammatory diseases is the focus of today’s clinical medicine. M1 type macrophages induce the inflammatory response and release proinflammatory mediators while M2 type inhibit inflammation via secreting antiinflammatory factors. The polarization of M1 type macrophages to M2 type changes from an inflammatory state to a state in which inflammation is inhibited. Therefore, studying the M2 type polarization of macrophages to relieve inflammation will be beneficial to the treatment of inflammatory diseases. To explore the molecular mechanism of bone marrowderived mesenchymal stem cell culture medium (BMSCCM) to induce the Raw264.7 cell differentiation towards M2 macrophages， bone marrowderived mesenchymal stem cells were derived from 3 weekold C57BL/6 mice. We induced Raw264.7 cells to M1 macrophage with lipopolysaccharide (LPS，1 μg/mL). Then we cultured these Raw264.7 cells in culture mediums which were previously used to culture bone marrowderived mesenchymal stem cells. The mRNA relative expression of TNFα, INOS, ARG1, TGFβ1 and IL10 was detected by semiquantitative PCR. Western blotting was used to detect the expression level of proteins involved in the STAT3 signaling pathway. After cultured in BMSCCM and induced by LPS, M2 markers (ARG1, TGFβ1) and IL10 of the Raw264.7 cells was increased and the pSTAT3 protein level was promoted significantly. The results show that BMSCCM can induce Raw264.7 cells differentiation towards M2 macrophages by promoting STAT3 phosphorylation via IL10/STAT3 signaling pathway.
