间充质干细胞对H-2半相合骨髓移植小鼠免疫功能的影响

Effect of bone marrow mesenchymal stem cells on immunoregulation in H-2 haploidentical bone marrow transplantation mice

目的探讨骨髓间充质干细胞(MSC)对半相合骨髓移植小鼠免疫功能的影响及机制。方法经8 Gy ^(60)Coγ射线照射后,BALB/c(H-2~d)雌性小鼠分为两组:MSC 组,尾静脉输注经 cm-Dil 膜染剂标记的 CB6F1(H-2^(bd))雌性小鼠的 MSC 和 CB6F1雄性小鼠的骨髓及脾的单个核细胞;对照组,单独输注 CB6F1骨髓及脾的单个核细胞。观察两组移植后不同时间外周血中的淋巴细胞亚群,ConA 和LPS 刺激的 T、B 淋巴细胞增殖,供受者及第三者混合淋巴细胞反应(MLR),供者骨髓及脾细胞在受者胸腺、骨髓和脾脏的植入率,供者 MSC 在受者体内分布,急、慢性 GVHD 的发生率和生存分析。结果移植后90天(+90天)内,MSC 组 CD3阳性细胞高于对照组(P<0.05),+30天 MSC 组 CD3CD4双阳性细胞百分比和 CDg/CD8值高于对照组(P<0.05)。两组 T 细胞增殖活性差异无统计学意义。MSC组+14天后 B 细胞增殖功能开始恢复,+30天达到正常值,而对照组+60天才恢复到正常值。供受者的 MLR 中 MSC 组的 RR 值始终低于对照组;第三者 MLR 中 MSC 组与对照组差异无统计学意义。+30天 MSC 组受者骨髓和脾中的 sry 基因多于对照组。移植后 MSC 主要集中在胸腺、骨髓、肝、小肠,并且大量扩增。对照组急性 GVHD 发生率高于 MSC 组(P<0.05),+90天对照组出现不同程度的慢性 GVHD,MSC 组+120天后出现慢性 GVHD,程度轻于对照组。MSC 组存活率高于对照组(P<0.05)。结论 MSC 促进骨髓干细胞植入,加快 CD4淋巴细胞恢复,促进体液免疫恢复,减少GVHD 发生率,并且在受者胸腺、骨髓、肝、肠和心内膜下大量扩增,起到修复损伤作用,提高半相合骨髓移植动物生存率。

Objective To explore immunoregulatory mechanism of mesenehymal stem cells （MSCs） in H-2 haploidentieal bone marrow cells transplantation mice. Methods BALB/e female mice irradiated with 8Gy ^60Co γ-rays were divided into two groups： MSCs group, infused cm-DiI labeled MSCs from female CB6F1 mice and monocytes from the bone marrow and spleen of male CB6F1 ;Control group, only infused monocytes from the bone marrow and spleen of male CB6F1. T-lymphocyte subpopulation of peripheral blood cells, T and B cells proliferation stimulated by ConA and LPS, mixed lymphocyte reaction between donor and recipient and third part, the sry-gene chimerism of bone marrow, spleen and thymus of the recipient, the distribution of MSCs in the recipient, the incidence rate of GVHD and survival were observed. Results The CD3 at ＋ 90 d the percent of CD3^＋ CD4^＋ cells, and CD4-/CD8 at ＋ 30 d in the MSCs group were higher than that in control post-transplantation, respectively（ P 〈 0.05）. The proliferation activity of B cells recovered more rapidly and that of T cells recovered comparably in MSCs group as compared with that in control group. The result of MLR between donor and recipient was lower in MSCs group than that in the control; and that between recipient and the third part had no difference. The sry-gene chimerism of bone marrow and spleen of the recipient was higher in MSCs group than in control at ＋ 30 d. The MSCs mainly distributed in intestine, thymus, bone marrow, liver, heart of the recipient after transplation. The incidence of acute GVHD was higher and the survival rate was lower in MSCs group than that in control group （P 〈 0.05）. Chronic GVHD occurred in the control group at ＋ 90 d, while in the MSCs group at ＋ 120 d. Conclusions MSCs might improve stem cell emgraftment, promote lymphcyte and humoral immunity recovery, decrease incidence of GVHD and increase survival by inducing specific immunologic tolerance and repairing organs injuries.