目的 观察髓源性抑制细胞（MDSCs）在荷瘤小鼠肺部组织的表达情况。方法 取12只C57BL/6小鼠随机分为实验组和对照组，每组6只。实验组：将体外培养的3LL细胞（0.3×106个）注射入小鼠尾静脉，成瘤后3周取小鼠肺组织，酶消化肺组织，制备肺组织单细胞悬液，采用流式细胞术检测MDSCs（GR1-FITC、CD11b-PE双染阳性）的表达量。对照组：在小鼠尾静脉注射PBS，其余步骤同实验组。结果 实验组小鼠肺部组织高表达免疫抑制细胞MDSCs（GR+CD11b+双阳性），表达量为（19.92±6.08）%；对照组MDSCs表达量为（7.06±2.67）%，两组比较差异有统计学意义（P<0.001）。结论 肺癌小鼠的肺组织高表达免疫抑制细胞MDSCs。

Objective To observe the expression of myeloid-derived suppressor cells (MDSCs) in lung tissues of tumor-bearing mice. Methods Twelve C57BL/6 mice were randomly divided into experiment group and control group, with 6 mice in each group. 3LL cells (0.3×106) cultured in vitro were injected into tail vein of mice in experiment group, and mouse lung tissues were obtained three weeks after tumor formation. Lung single cell  suspension was made with mixture of enzyme, and the expression of MDSCs (GR1-FITC and CD11b-PE double positive staining) was detected by flow cytometry. PBS was injected into tail vein of mice in control group, and the following treatment was the same as that in experiment group.ResultsMDSCs were highly expressed (19.92%±6.08%) in lung tissues of mice in experiment group (GR+CD11b+ double positive staining), that in control group was 7.06%±2.67%, and there were significant differences between two groups (P<0.001）. Conclusion MDSCs are highly expressed in lung tissues of mice with lung cancer.