大鼠骨髓间充质干细胞和免疫调节作用

目的 研究一氧化氮(nitric oxide,NO)在骨髓间充质干细胞(mesenchymal stem cells,MSCs)的免疫调节作用.方法 贴壁筛选法分离培养Lewis大鼠骨髓间充质干细胞.以刀豆蛋白A(concanavalin A,ConA)作为刺激因素,SD大鼠外周血分离的T淋巴细胞作为反应细胞,采用CCK-8法检测T淋巴细胞与MSCs共培养后其增殖能力的变化.然后采用RT-PCR、Western blot检测MSCs诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)mRNA与蛋白的表达;Griess法检测上清液亚硝酸盐含量;ELISA检测上清液Th1细胞因子IFN-γ和Th2细胞因子IL-4的水平.结果 MSCs明显抑制ConA诱导的T淋巴细胞增殖,抑制作用因细胞比例的不同而有所区别.当实验组MSC:T为1:10时最明显,增殖率为(33.83±2.10)%,而1:80组[(78.62±3.80)%]与不含MSCs的阳性对照组[(79.03±1.70)%]差异无统计学意义(P＞0.05).实验组MSCs的iNOS mRNA与蛋白的表达以及上清液中亚硝酸盐含量均较阳性对照组明显上调,1:10～1:40的范围内呈明显递增趋势,但1:80组与1:40组差异无统计学意义(P＞0.05).在加入iNOS特异性抑制剂2-甲基-2-巯基硫酸脲(S-methylisothiourea sulfate,SMT)后,各组T淋巴细胞增殖率基本恢复.实验组IFN-γ含量随MSCs所占比例的降低而增加,各组IL-4含最差异无统计学意义(P＞0.05).结论 MSCs对同种异体外周血T淋巴细胞的增殖有免疫调节作用,机制可能与其分泌的可溶性因子NO影响了 Th1/Th2平衡有关.

Abstract：

Objective To observe the role of nitric oxide(NO) in the immune regulatory effect of bone marrow mesenchymal stem cells(MSCs). Methods Bone marrow MSCs were isolated from Lewis rats by adherence screening. Concanavalin A (ConA) was adopted as the stimulator and T-lymphocyte isolated from peripheral blood of SD rats as the reactive cells. The changes of the ability of T-lymphocyte proliferation, when co-cultured with MSCs, were measured by CCK-8 assay. The inducible nitric oxide synthase (iNOS) mRNA and protein expression on MSCs and were detected by RT-PCR, Western blot. The contents of nitrites and the levels of Th1 type cytokine IFN-γand Th2 type cytokine IL-4 were measured by Griess test and ELISA respectively, in the co-cultured supernatant. Results T-lymphocyte proliferation was inhibited by co-cultured MSCs, which was concentration-dependent. In this study, the inhibition was most obviously group[ (79.03 ± 1.70)% ] (P ＞ 0.05 ). The I NOS mRNA expression, protein and nitrite levels were signifigroups, the proliferation rate of T-lymphocyte recovered. The content of IFN-γwas increased with the ratio decline of MSCs in the experimental group and IL-4 in each group has no significant difference( P ＞ 0.05 ).Conclusion MSCs inhibited T-lymphocyte proliferation by influencing Th1/Th2 balance, and the secretion of soluble factor NO, which secreted by MSCs, may plays an important role in the immune regulation.

Immunosuppressive effects and mechanism of rat bone marrow mesenchymal stem cells on allogeneic T lymphocytes

Objective To observe the role of nitric oxide(NO) in the immune regulatory effect of bone marrow mesenchymal stem cells(MSCs). Methods Bone marrow MSCs were isolated from Lewis rats by adherence screening. Concanavalin A (ConA) was adopted as the stimulator and T-lymphocyte isolated from peripheral blood of SD rats as the reactive cells. The changes of the ability of T-lymphocyte proliferation, when co-cultured with MSCs, were measured by CCK-8 assay. The inducible nitric oxide synthase (iNOS) mRNA and protein expression on MSCs and were detected by RT-PCR, Western blot. The contents of nitrites and the levels of Th1 type cytokine IFN-γand Th2 type cytokine IL-4 were measured by Griess test and ELISA respectively, in the co-cultured supernatant. Results T-lymphocyte proliferation was inhibited by co-cultured MSCs, which was concentration-dependent. In this study, the inhibition was most obviously group[ (79.03 ± 1.70)% ] (P ＞ 0.05 ). The I NOS mRNA expression, protein and nitrite levels were signifigroups, the proliferation rate of T-lymphocyte recovered. The content of IFN-γwas increased with the ratio decline of MSCs in the experimental group and IL-4 in each group has no significant difference( P ＞ 0.05 ).Conclusion MSCs inhibited T-lymphocyte proliferation by influencing Th1/Th2 balance, and the secretion of soluble factor NO, which secreted by MSCs, may plays an important role in the immune regulation.