白细胞介素4降低脐带间充质干细胞对造血干细胞分化潜能的维持能力

目的探讨白细胞介素4（IL-4）对脐带间充质干细胞（UC-MSC）维持造血干细胞分化的影响。 方法将UC-MSC与脐带血CD34⁺造血干细胞按照造血支持能力常用的方案共培养，实验分为对照组和IL-4组，IL-4处理组加入IL-4（20 ng/ml）培养14 d。收集细胞并计数，使用流式细胞仪检测表达CD34的细胞比例。取3×10³个细胞，加入到半固体培养基，培养14 d后，通过倒置显微镜观察比较各种集落的形成，并使用流式细胞仪分析其中巨噬细胞和粒细胞表面特异性蛋白CD11b、CD14和CD15的表达。对两独立样本进行t检验统计学分析。 结果加入IL-4后，共培养体系中细胞数量（1.31±0.05）×10⁵个/孔与对照组（2.80±0.28）×10^5?个/孔相比下降，差异有统计学意义（t = 7.31，P < 0.05），并且流式细胞分析显示其中的CD34⁺细胞比例也有降低。3×10³个IL-4组得到的细胞形成巨噬细胞集落形成单位的能力（9.33±1.53）?个/孔较对照组（17.67±0.58）个/孔有明显下降，差异有统计学意义（t = 8.84，P?< 0.001）；形成粒-巨噬集落形成单位的能力（15.67±3.22）个/孔较对照组（29.33±4.04）?个/?孔有明显下降，差异有统计学意义（t = 4.58，P < 0.05）；形成总集落单位的能力（39.33±9.07）个/?孔较对照组（62.67±6.66）?个/?孔也有下降，差异有统计学意义（t = 3.59，P < 0.05）。IL-4组得到的细胞分化出的细胞总数（3.67±1.71）×10⁵个/孔与对照组（9.50± 3.13）×10⁵个/孔相比也明显下降，差异有统计学意义（t = 2.83，P < 0.05），而流式细胞术分析发现分化成的细胞中CD14⁺细胞比例也下降。 结论IL-4可以降低UC-MSC对造血干细胞分化潜能的维持能力，提示在Ⅱ型辅助T细胞相关体液免疫疾病中使用间充质干细胞治疗时，也需要兼顾机体造血相关功能。

Interleukin-4 reduces the supportive ability of umbilical cord mesenchymal stem cells on differentiation potentialof hematopoietic stem cells

ObjectiveUmbilical cord mesenchymal stem cells (UC-MSC) are a hot research field because of its unique advantages. UC-MSC possess the ability of maintaince the differentiation potential of hematopoietic stem cells, and we studied the effect of interleukin-4 on this ability. MethodsUmbilical cord mesenchymal stem cells were co-cultured with cord blood CD34⁺ cells with or without IL-4. CD34⁺ cells were counted after 14 days. Moreover, colony forming ability of cells was evaluated. CD11b, CD14 and CD15 expression of cells from colony forming assay was assayed by flow cytometry. Statistical analysis was performed by unpaired t-test. After IL-4 was added, the number of cells (1.31±0.05) ×10⁵ cells/well decreased significantly compared with the control group (2.80±0.28) ×10⁵ cells/well (t = 7.31, P < 0.05) , and flow cytometry analysis showed that the proportion of CD34⁺ cells in the co-culture system also decreased. The ability of IL-?4-treated cells to form colony forming unit-macrophage (9.33±1.53 per well) was significantly lower than that of the control group (17.67±0.58 per well, t = 8.84, P < 0.001) ; The ability to form colony forming unit-granulocyte/macrophage (15.67±3.22 per well) was significantly lower than that of the control group (29.33±4.04 per well, t = 4.58, P < 0.05) . The ability to form total colony forming units (39.33±9.07 per well) was also lower than that of the control group (62.67±6.66 per well, t = 3.59, P < 0.05) . The total number of cells differentiated from IL-4 group (3.67±1.71) ×10⁵ cells/well was also significantly lower than that of the control group (9.50±3.13) ×10⁵ cells/?well, (t = 2.83, P < 0.05) , and flow cytometry analysis showed that the ratio of CD14⁺ cells in differentiated cells was also lower. ConclusionIL-4 can reduce the maintenance ability of umbilical cord mesenchymal stem cells on hematopoietic stem cells differentiation, suggesting that when mesenchymal stem cells are used in treatment of type II helper T cell-related humoral immune diseases, the hematopoietic related functions should also be considered.