目的 探索昆布多糖基于调节巨噬细胞极化抑制肺纤维化的作用机制。方法 将昆布中提取的硫酸多糖经自由基降解，得到低相对分子质量昆布多糖（low molecular weight fucoidan，LMWF），并通过高效液相色谱测定了其单糖结构组成。通过免疫组化检测肺纤维化小鼠与LMWF治疗组小鼠M2巨噬细胞极化生物标志物的表达，并通过Western blotting和qRT-PCR检测M1/M2标志物的表达。分别用脂多糖（lipopolysaccharide，LPS）联合γ干扰素（interferon-γ，IFN-γ）和白细胞介素-4（interleukin-4，IL-4）诱导MH-S细胞，构建体外M1和M2巨噬细胞极化模型，探索LMWF调节巨噬细胞极化延缓肺纤维化的作用机制。结果 LMWF可显着降低肺纤维化小鼠肺组织中M1/M2巨噬细胞标志物的表达（P＜0.05、0.01、0.001）。同样，LMWF可有效抑制细胞模型中M1和M2型标志物的表达（P＜0.05、0.01、0.001）。结论 LMWF可以通过早期抗炎作用调节M1巨噬细胞极化，并在后期通过抑制M2巨噬细胞极化有助于减少纤维化。

Objective To exploring the mechanism of Ecklonia kurome polysaccharides in inhibiting pulmonary fibrosis by regulating macrophage polarization. Methods Low molecular weight fucoidan (LMWF) was obtained by free radical degradation of sulfated polysaccharide extracted from E. kurome, and its monosaccharide structure was determined by high performance liquid chromatography. The expressions of polarized biomarkers in M2 macrophages of pulmonary fibrosis mice and LMWF treated mice were detected by immunohistochemistry, and the expressions of M1/M2 markers were detected by Western blotting and qRT-PCR. Lipopolysaccharide (LPS) combined with interferon-γ (IFN-γ) and interleukin-4 (IL-4) were used to induce MH-S cells respectively, and the polarization models of M1 and M2 macrophages in vitro were constructed to explore the mechanism of LMWF in regulating macrophage polarization and delaying pulmonary fibrosis. Results LMWF significantly decreased the expressions of M1/M2 macrophage markers in lung tissue of mice with pulmonary fibrosis (P < 0.05, 0.01, 0.001). Similarly, LMWF effectively inhibited the expressions of M1 and M2 markers in cell model (P < 0.05, 0.01, 0.001). Conclusion LMWF can regulate the polarization of M1 macrophages through anti-inflammatory effect in the early stage, and help to reduce fibrosis by inhibiting the polarization of M2 macrophages in the later stage.

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山东省自然科学基金联合基金资助项目（ZR2021LZY030）；临沂大学大学生创新创业训练计划项目（X202210452199）