炎症性疾病的发生是当今临床医学攻克的重点。M1型巨噬细胞分泌炎症因子产生炎症, 而M2型巨噬细胞分泌抑炎因子抑制炎症的发生。M1型巨噬细胞向M2型极化, 则是从炎症状态转变成抑制炎症发生的状态, 因此研究巨噬细胞向缓解炎症的M2型极化将有利于炎症性疾病的治疗。本研究利用骨髓间充质干细胞(BMSC)培养液处理已被脂多糖(LPS)诱导呈M1型的Raw264.7巨噬细胞, 探究骨髓间充质干细胞培养液(BMSC-CM)对巨噬细胞向M2型极化的影响及其分子机制。提取来源于3周龄C57BL/6鼠的骨髓间充质干细胞; 再收集BMSC-CM处理M1型的Raw264.7巨噬细胞; 半定量PCR检测M1型标记基因[肿瘤坏死因子α(TNF-α)和诱导型一氧化氮合酶(INOS)]和M2型标记基因[精氨酸酶1(ARG-1)和转化生长因子β1(TGF-β1)]mRNA表达以及白介素10(IL-10)mRNA表达水平; Western蛋白质印迹法检测信号传导及转录激活蛋白3(STAT3)和磷酸化STAT3(p-STAT3)的表达。本研究发现,经过BMSC-CM培养后的M1型的Raw264.7巨噬细胞, 其M2型相关指标ARG-1和TGF-β1 mRNA水平明显上升, 并且IL-10 mRNA水平和p-STAT3蛋白水平也明显上升。这些结果说明,骨髓间充质干细胞培养液通过IL-10/STAT3信号通路促进STAT3磷酸化, 诱导巨噬细胞Raw264.7细胞向M2型极化。

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 anti-inflammatory 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 marrow-derived mesenchymal stem cell culture medium (BMSC-CM) to induce the Raw264.7 cell differentiation towards M2 macrophages, bone marrow-derived mesenchymal stem cells were derived from 3 week-old 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 marrow-derived mesenchymal stem cells. The mRNA relative expression of TNF-α, INOS, ARG-1, TGF-β1 and IL-10 was detected by semi-quantitative PCR. Western blotting was used to detect the expression level of proteins involved in the STAT3 signaling pathway. After cultured in BMSC-CM and induced by LPS, M2 markers (ARG-1, TGF-β1) and IL-10 of the Raw264.7 cells was increased and the p-STAT3 protein level was promoted significantly. The results show that BMSC-CM can induce Raw264.7 cells differentiation towards M2 macrophages by promoting STAT3 phosphorylation via IL-10/STAT3 signaling pathway.