脐带间充质干细胞对狼疮鼠免疫细胞亚群的调节作用

Umbilical cord mesenchymal stem cell modulates immune cell subsets in lupus mice

目的探讨脐带间充质干细胞（UC-MSCs）移植治疗狼疮鼠后免疫细胞亚群变化，为阐明UC-MS（3s治疗SLE机制提供依据。方法将B6-MRL-Fas虹狼疮鼠采用随机数字表法随机分成3组：UC-MSCs治疗组、成纤维样滑膜细胞（FLs）治疗组与未治疗组；经尾静脉分别输注1×10^6UC-MSCs或FLS；治疗4周后，计算小鼠脾脏指数，苏木精．伊红（HE）染色观察小鼠肾脏病变，ELISA试剂盒检测IgG水平，流式细胞仪检测脾脏中各淋巴细胞亚群及腹腔和肾脏巨噬细胞比例，统计学方法采用方差分析。结果UC．MSCs治疗组狼疮鼠脾脏指数[（79±9）mg／10g]、血清IgG水平[（7．5±1．5）mg／ml]均较FLS组[（147±23）mg／10g，t=2．78，P〈0．01][（17．0±2．8）mg／ml，t=3．00，P〈0．01]及未治疗组[（156±16）mg／10g，t=4．29，P〈0．01][（16．7±1．6）mg／ml，t=4．01，P〈0．01]显著下降；FLS组[（2．412±0．297）％]及未治疗组[（2．612±0．318）％]脾脏浆细胞B220-CD138＋的比例显著高于UC—MSCs治疗组[（0．306±0．017）％]（t=7．07，P〈O．01；与t=7．22，P〈0．01）；UC—MSCs治疗组脾脏调节性T细胞（CD25＋Foxp3＋／CD4＋调节性T细胞）比例[（15．08±0．81）％]显著高于FLS组[（8．80±0．23）％，t=7．39，P〈0．01]及未治疗组[（8．02±0．47）％，t=7．45，P〈O．01]；UC—MSC组脾脏滤泡辅助T细胞（CXCR5＋PD1＋／CD4＋Tfh）比例[（14．3±1．5）％]及IFNγ＋／CD4＋Th1细胞比例[（1．78±0．27）％）]显著低于FLS组[（28．8±2．2）％，t=5．49，P〈0．01；（4．88±0．81）％，t=3．61，P〈0．01]及未治疗组[（31．5±3．3）％，拉5．25，P〈0．01；（5．93±1．56）％，t=2．60，P〈O．05]；UC—MSC治疗后，狼疮鼠肾脏巨噬细胞F4／80＋比例[（3．52±0．37）％]显著高于未治疗组[（1．58±0．29）％，t=3．25，P〈O．01]，但是与FLS组[（3．08±0．18）％，t=O．40，P〉0．05]差异无统计学意义。但是，3组小鼠脾脏IL-4＋／CD4＋Th2及IL-17＋／CD4＋Th17亚群及腹腔巨噬细胞差异均无统计学意义。结论UC—MSCs治疗SLE的机制可能通过增加调节性T细胞和肾脏巨噬细胞，并降低Tfh、Th1和浆细胞。

Objective The purpose of this study is to observe the changes of immune cell subsets in lupus mice after umbilical cord mesenchymal stem cells （UC-MSCs） transplantation. Methods B6.MRL-Faslpr lupus mice were randomly divided into the following three groups： the UC-MSCs treated group, the fibroblast like synoviocytes （FLS） treated group and the untreated group. MSC （lxl06） or FLS （1×10^6） were injected into the tail vein of lupus mice respectively. Four weeks after treatment, the spleen index was calculated. The pathological changes of kidney were assessed by HE staining. The frequencies of immune cell subsets in spleen and macrophage in kidney as well as abdominal cavity were analyzed by flow cytometry. Data were analyzed with t test. Results The spleen index of UC-MSCs treated lupus mice [（79±9） mg/10 g] and IgG level [（7.5±1.5） mg/ml] were significantly decreased when compared with FLS treated group [（147±23） mg/10 g, t=2.78, P〈0.01] [（17.0±2.8） mg/ml, t=3.00, P〈0.01] and the untreated group [（156±16） mg/10 g, t=4.29, P〈0.01] [（16.7±1.6） mg/ml,t=4.01, P〈0.01]. HE staining also showed that the pathological changes of kidney were alleviated after MSCs transplantation. In addition, the frequency of plasma cells in the untreated group [（2.612±0.318）% vs （0.306±0.017）%, t=7.22, P〈0.01] and the FLS treated group [（2.412±0.297）% vs （0.306±0.017）%, t=7.07, P〈0.01] were markedly higher than MSCs treatment [（0.306±0.017）%]. Moreover, the frequency of CD25＋Foxp3＋/CD4＋ Treg in the MSCs treated group [（15.08±0.81）%] was significantly increased compared with the untreated group [（8.02±0.47）%, t=7.45, P〈0.O1] and FLS treated group [（8.80±0.23）%, t=7.39, P〈0.01]. MSCs treatment resulted in a decrease in CXCR5＋PDI＋/CD4＋Tfh and IFNγ/CD4＋Th1 subset, compared with the untreated group [（14.3±1.5）% vs （31.5±3.3）%, t=5.25, P〈0.01] [（1.78±0.27）% vs （5.93±1.56）%, t=2.60, P〈 0.05] and the FLS treated group [（14.3±1.5）% vs （28.8±2.2）%, t=5.49, P〈0.01] [（1.78±0.27）% vs （4.88±0.81）%, t=3.61, P〈0.01]. The frequency of macrophage in kidney of the MSCs treated group [（3.52±0.37）%] was markedly increased compared with the untreated group[（1.58±0.29）%, t=3.25, P〈0.01], while neither the IL4＋/ CD4＋Th2 subset nor the IL17＋/CD4＋Thl7subset and the frequency of macrophage in abdominal cavity showed significant changes in the three groups. Conclusion ＇ These findings suggest that the therapeutic effects of MSCs on lupus mice may mediate through increasing the frequency of spleen Treg and renal macrophage and decreasing the frequency of Tfh, Thl and plasma cells.