骨髓间充质干细胞输注对MRL/lpr狼疮鼠B淋巴细胞CXCR4表达的影响

Effects of bone marrow mesenchymal stem cells infusion on CXCR4 expression in B cells of MRL/lpr lupus mice

目的:研究骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSCs)输注对狼疮鼠血浆C3、IgG浓度及B细胞、浆细胞表面CXCR4表达的影响,分析BMMSCs改善系统性红斑狼疮疾病活动的机制。方法:分离培养C57BL/6小鼠的BMMSCs,并对MRL/lpr狼疮鼠进行尾静脉输注。实验分为C57BL/6组(C57BL/6小鼠未进行尾静脉输注)、MRL/lpr组(MRL/lpr鼠未进行尾静脉输注)、BMMSCs组(MRL/lpr鼠12周龄注射BMMSCs)和PBS组(MRL/lpr鼠12周龄注射PBS)。在20周末取小鼠的外周血、骨髓、脾脏进行流式细胞分析,检测B细胞、浆细胞表面CXCR4表达;同时取4组血浆,酶联免疫吸附试验(ELISA)检测C3、IgG浓度。取小鼠肾脏组织行苏木精伊红(HE)染色。结果:①MRL/lpr组较C57BL/6组小鼠血浆C3浓度明显降低、IgG浓度明显增高(P均<0.01);MRL/lpr组较C57BL/6组小鼠B细胞表面CXCR4的表达在外周血明显下降,在骨髓和脾脏明显升高(P均<0.01);MRL/lpr组小鼠骨髓(P<0.05)及脾脏(P<0.01)浆细胞表面CXCR4表达明显高于C57BL/6小鼠。②BMMSCs组较PBS组、MRL/lpr组C3浓度明显升高、IgG浓度明显降低(P均<0.01);BMMSCs组较PBS组B细胞表面CXCR4表达在外周血明显增加(P<0.01),在骨髓(P<0.01)和脾脏(P<0.05)明显下降,较MRL/lpr组在骨髓和脾脏均明显下降(P均<0.01)。③BMMSCs组较PBS组、MRL/lpr组浆细胞表面CXCR4表达在骨髓和脾脏均明显降低(P均<0.05)。④肾脏HE染色提示输注BMMSCs后狼疮鼠肾脏炎症改善。结论:BMMSCs输注可调节B细胞、浆细胞表面CXCR4的表达,改善MRL/lpr鼠病情活动指标。

Objective:To study the effects of bone marrow mesenchymal stem cells(BMMSCs)infusion on plasma C3 and IgG concentrations,and CXCR4 expression of B cells and plasma cells in MRL/lpr lupus mice,and to explore the mechanism of BMMSCs in regulating disease activity of systemic lupus erythematosus.Methods:BMMSCs were isolated from C57BL/6 mice and cultured,and then injected into MRL/lpr lupus mice by tail transfusion.All mice were divided into C57BL/6 group(C57BL/6 mice were not injected),MRL/lpr group(MRL/lpr mice were not injected with BMMSCs),BMMSCs infusion group(MRL/lpr mice were injected with BMMSCs at 12 weeks),and PBS control group(MRL/lpr mice were injected with PBS at 12 weeks).At the end of the 20th week,peripheral blood,bone marrow and spleen of mice were taken for flow cytometry analysis to detect CXCR4 expression in B and plasma cells,and then the plasma of the 4 groups were taken for ELISA to detect IgG and C3 level.The kidney of mice was stained with hematoxylin-eosin.Results:①Compared with the C57BL/6 group,the plasma C3 level were decreased and IgG level were significantly increased in the MRL/lpr group(all P<0.01).Compared with C57BL/6 group,the expression of CXCR4 on B cell surface in MRL/lpr group was significantly decreased in peripheral blood,and was significantly increased in bone marrow and spleen(all P<0.01).The proportion of CXCR4 on plasma cell surface in bone marrow(P<0.05)and spleen(P<0.01)of MRL/lpr group was significantly higher than that of C57BL/6 mice.②Compared with PBS or MRL/lpr group,the level of C3 in BMMSCs group was significantly increased,while the level of IgG was significantly decreased(all P<0.01).Compared with the PBS group,the expression of CXCR4 on B cell surface of BMMSCs group was significantly increased in peripheral blood(P<0.01),and significantly decreased in bone marrow(P<0.01)and spleen(P<0.05).Compared with the MRL/lpr group,the expression of CXCR4 on B cell surface of bone marrow and spleen was significantly decreased(all P<0.01).③Compared with PBS group or MRL/lpr group,the expression of CXCR4 on plasma cell surface in bone marrow and spleen of BMMSCs group was significantly decreased(all P<0.05).④Renal HE staining suggested attenuation of renal inflammation in MRL/lpr mice after infusion of BMMSCs.Conclusion:BMMSCs infusion can regulate the expression of CXCR4 on the surface of B and plasma cells and improve the disease activity index of MRL/lpr mice.