骨髓间充质干细胞联合胰岛移植对受体鼠树突状细胞成熟和功能的影响

The effect of co-transplantation of bone marrow-derived mesenchymal stem cells and islet on maturation and function of bone marrow-derived dendritic cells in recipient mice

目的：研究骨髓问充质干细胞（MSCs）对骨髓细胞（BMC）分化为成熟树突状细胞（DCs），以及MSCs联合胰岛移植对受体鼠BMC来源DCs成熟和功能的影响，以探讨MSCs如何通过OCs发挥免疫抑制作用的机制。方法：将BALB／e小鼠分离纯化骨髓MSCs按比例加入C57BL／6小鼠BMC，在含重组鼠粒细胞-巨噬细胞集落刺激因子（rmGM-CSF）和重组鼠自介素4（rmIL-4）的培养条件下制备DCs，加脂多糖（LPS）促DCs成熟，检测各组DCs免疫表型的变化，抗原摄取及其分泌白细胞介素一12的能力。观察MSCs联合胰岛移植的同种异基因糖尿病模型小鼠的血糖和组织学变化，并取受体鼠BMC体外诱导为DCs，检测成熟DCs免疫表型、抗原摄取和分泌IL-12能力。结果：体内外实验证明MSCs可使BMC来源的DCs表型CD11c，成熟表面标志CD83、协同刺激分子CD86和I—A^b表达明显降低（P〈0．05），抗原摄取和分泌IL—12能力显著下降（P〈0．01）。MSCs联合胰岛移植，可抑制同种异基因受体鼠免疫排斥反应的发生。结论：MSCs可通过抑制BMC来源的DCs的成熟和功能，降低DCs抗原摄取和分泌IL一12能力，诱导免疫耐受，减轻对移植胰岛的排斥反应的发生。

AIM： To investigate the effect of transplantation of bone marrow-derived mesenchymal stem cells （ MSCs）, or coransplantation of islet and MSCs, on maturation and function of bone marrow-derived dendritic cells （DCs） in recipient mice. METHODS： Bone marrow MSCs were isolated from BALB/c mice and co-cultured with bone marrow mononuclear ceils （BMCs） from CS？BL/6 mice at indicated ratios. The co-cultures were treated with recombinant mice granulocyte-macro-phage colony-stimulating factor （rmGM-CSF） and recombinant mice IL-4 （rmlL-4） for 7 days to induce the differentiation of DCs, with lipopolysaccharide （LPS） favoring the maturation of DCs. The differentiation markers and antigen uptake capability of DCs were analyzed by FCM. Production of Interleukin-12 in the superna- rants of the DC cultures was quantified by ELISA. BALB/c- derived MSCs and islet were co-transplanted to the capsule of kidney in allogeneic C57BL/c mice. The recipient mice were assayed for their tissue morphology, blood glucose level, and the in vitro differentiation ability of their BMC into mature and functional DCs. RESULTS： The transplantation of MSCs prevented BMC from differentiating into mature Des, as shown by down-regulated surface markers of DCs including CDllc, CD83, CD86 and I-Ab （ P 〈 0. 05）, impaired antigen uptake and decreased IL-12 secretion （ P 〈0.0]）. Co-transplantation of MSCs and islet inhibited immune rejection in the allogeneic recipient mice. CONCLUSION： Transplantation of MSCs inhibits maturation and function of monocyte-derived dendritic cells in the recipient mice, resulting in immune tolerance for the allogeneic islet.