骨髓间充质干细胞预防手术后肿瘤肺转移动物模型研究

背景与目的:近年来研究发现,肿瘤患者术后髓系抑制细胞(myeloid-derived suppressor cells,MDSCs)较术前升高,且其促肿瘤血管生成和肿瘤生长作用增强,骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)可抑制MDSCs活化与增殖.但围手术期MDSCs的变化与肿瘤术后转移的关系及BMSCs能否通过抑制MDSCs预防手术后肿瘤转移尚不清楚.该研究拟探讨围手术期MDSCs变化与手术后肿瘤转移的相关性及BMSCs对围手术期MDSCs和手术后肿瘤转移的影响.方法:C57BL/6小鼠经尾静脉注射LLC细胞后分为4组:对照组(C组)、麻醉组(A组)、麻醉后开腹组(AL组)及麻醉后开腹并肝叶切除组(ALH组).AL组小鼠手术后分为2组:术后无治疗组(AL1组)和术后给予同系BMSCs治疗组(ALB组).流式细胞术检测小鼠外周血单个核细胞(peripheral blood mononuclear cells,PBMCs)中Gr-1+CD11b+细胞的含量;第14天计数小鼠肺表面转移灶.小鼠骨髓细胞体外诱导MDSCs体系中加入BMSCs共培养的方法探讨BMSCs对MDSCs生成的影响.结果:与C、A组相比,AL和ALH组小鼠肺转移灶显著增多(P<0.01);且ALH组较AL组显著增多(P<0.05).手术后AL和ALH组小鼠PBMCs中Gr-1+CD11b+细胞与C、A组相比显著升高;与AL组比较,ALH组Gr-1+CD11b+细胞显著升高.第14天,AL及ALB组小鼠肺表面转移灶数量分别为38.00±9.57和6.54±1.49,差异有统计学意义(P<0.01).ALB组小鼠PBMCs中Gr-1+CD11b+细胞与AL1组相比明显降低.小鼠骨髓细胞体外诱导MDSCs体系中加入BMSCs可显著抑制MDSCs的活化和增殖.结论:手术应激诱导MDSCs并促肿瘤肺转移形成,BMSCs可以抑制MDSCs的生成进而抑制手术后肺转移形成.

Bone marrow mesenchymal stem cells prevent pulmonary tumor metastasis after surgery in a mouse model

Background and purpose:In recent years, the studies indicated that postoperatively induced myeloid-derived suppressor cells (MDSCs) were qualified with potent proangiogenic and tumor-promotive ability. Bone marrow mesenchymal stem cells (BMSCs) significantly inhibited the induction and proliferation of MDSCs. However, the relationship of MDSCs and tumor metastasis during perioperative period, and whether BMSCs could prevent tumor metastasis through inhibiting MDSCs are not clariifed. This study aimed to investigate the change of MDSCs during perioperative period and its correlation with tumor metastasis after surgery, and the inlfuence of BMSCs on the induction of MDSCs and the development of postoperative tumor metastasis.Methods:LLC cells were injected intravenously into C57BL/6 mice. Two hours later, these mice were divided into 4 groups: controls (C group); mice given anesthesia (A group); mice given anesthesia and laparotomy (AL group) and mice given anesthesia, laparotomy, and hepatic lobectomy (ALH group). The AL mice were divided into 2 groups after surgical operation: the AL mice without treatment (ALL group) and the AL mice treated with syngeneic BMSCs (ALB group). The percentage of Gr-1+CD11b+ cells in peripheral blood mononuclear cells (PBMCs) was detected by flow cytometry. The numbers of metastases on the lung surface were counted on the 14th day after LLC infusion. BMSCs were also co-culturedin vitro with myeloid cells in order to illustrate the effects of BMSCs on the generation of MDSCs.Results:The numbers of lung metastases in AL and ALH group signiifcantly increased as compared with C and A group (P<0.01). The number of lung metastases in ALH group signiifcantly increased as compared with AL group (P<0.05). The percentage of Gr-1+CD11b+ cells in PBMCs during postoperative period signiifcantly increased in AL and ALH group as compared with C and A group, and the percentage of Gr-1+CD11b+ cells in ALH group also signiifcantly increased as compared with AL group. The numbers of lung metastases in AL and ALB group were (38.00±9.57) and (6.54±1.49), the difference was statistically signiifcant (P<0.01) on day 14 after LLC infusion. Meanwhile, the percentage of Gr-1+CD11b+ cells in ALB group signiifcantly decreased as compared with AL1 group. This study also demonstrated that BMSCs inhibited the induction and proliferation of MDSCs from myeloid cells in vitro.Conclusion:Surgery stress induces MDSCs and promotes tumor metastasis. Syngeneic BMSCs could inhibit the generation of MDSCs and further suppress tumor metastasis after surgery.