人脐血间充质干细胞移植修复骨髓造血损伤

文题释义：间充质干细胞：是一种多功能干细胞，由胚胎发育早期的中胚层发展而来，存在于人的各种组织、器官中，如骨、软骨、脂肪、外周血和肌肉等。骨髓组织中的间充质干细胞最多，但其在骨髓细胞中的比例仍很低，只有0.01%-1.00%，且年龄越大其含量越少，骨髓中的间充质干细胞分化能力也呈下降趋势。与骨髓相比，脐血中所含的间充质干细胞更加原始，因而有更强的增殖、分化能力。相较于骨髓间充质干细胞而言，人脐血间充质干细胞具有来源广泛、取材方便、无伦理方面的限制，使得人脐血间充质干细胞成为再生医学中的另一重要来源。骨髓造血损伤动物模型：建立骨髓造血损伤动物模型的方法有很多，主要分为物理方法、化学方法及物理化学方法等。物理方法包括各种射线，如X射线等，化学方法主要指以环磷酰胺为代表的烷化剂类化疗药物，而物理化学方法也叫混合性方法，联合应用放射线和化疗药物建立动物模型。  摘要背景：大多数研究间充质干细胞体外培养对造血干细胞的增殖作用和骨髓间充质干细胞移植可降低辐照引起的造血细胞死亡，增加骨髓细胞存活，修复造血功能，而少有研究人脐血间充质干细胞移植对骨髓造血损伤的修复。目的：探讨人脐血间充质干细胞对骨髓造血微环境的修复情况。方法：选用雄性BALB/c小鼠随机分为3组，实验组和对照组小鼠进行总剂量为6 Gy的X射线全身照射，建立骨髓造血损伤模型，正常组为未经处理的正常小鼠。实验组小鼠照射当天经尾静脉输入CM-DiL标记的人脐血间充质干细胞5×10⁶/只(0.2 mL)，对照组和正常组经尾静脉输入生理盐水0.2 mL，移植后第1，5，7，14，21天观察外周血血象恢复情况和骨髓造血微环境修复情况。结果与结论：①外周血常规：移植后第1，5，7天，实验组和对照组小鼠与正常组小鼠比较，白细胞、血小板、红细胞计数及血红蛋白浓度进行性下降，第7天下降最为明显，移植后第14天三系较前有所恢复，移植后第21天基本恢复正常，与实验组相比，对照组三系下降更为明显，移植后第14天实验组较对照组恢复快；②骨髓涂片情况：移植后第1，5，7，14天实验组及对照组小鼠骨髓出现造血功能抑制，以第7天最为明显，移植后第14天骨髓增生较前有所恢复，实验组优于对照组；移植后第21天实验组及对照组小鼠骨髓造血功能恢复，与正常组相比无差异；③骨髓病理切片情况：移植后第1，5，7，14天实验组及对照组小鼠骨髓出现造血功能抑制；移植后第14天实验组及对照组小鼠的骨髓造血功能较前开始恢复，实验组小鼠的骨髓增生情况优于对照组小鼠, 移植后第21天实验组及对照组小鼠骨髓增生情况与正常组比较无差异；④结果表明，人脐血间充质干细胞对骨髓造血功能恢复均有明显促进作用。ORCID: 0000-0002-7547-9664(高坤莉) 中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程

Transplantation of human umbilical cord blood mesenchymal stem cells in the repair of hematopoietic injury in bone marrow

BACKGROUND: A large number of studies mainly concern the proliferation effect of mesenchymal stem cells on hematopoietic stem cells in vitro and that bone marrow mesenchymal stem cell transplantation can reduce the death of hematopoietic cells caused by irradiation, increase the survival of bone marrow cells and repair hematopoiesis, while few of them investigate the repair of human umbilical cord blood mesenchymal stem cells transplantation on bone marrow hematopoiesis injury. OBJECTIVE: To explore the repair of hematopoietic microenvironment of bone marrow by human umbilical cord blood mesenchymal stem cells. METHODS: Male BALB/c mice were randomly divided into three groups. The mice in experimental group and control group were irradiated with total dose of 6-Gy X-ray to establish a mouse model of bone marrow hematopoietic injury. The normal group contained untreated normal mice. In the experimental group, CM-DiL labeled human umbilical cord blood mesenchymal stem cells were injected into the tail vein of each mouse at 5×10^6 (0.2 mL). The control group and the normal group received normal saline 0.2 mL through the tail vein. The peripheral blood hematology and bone marrow hematopoietic microenvironment repair were observed at 1, 5, 7, 14 and 21 days after cell transplantation. RESULTS AND CONCLUSION: Peripheral blood condition: At 1, 5 and 7 days after transplantation, the leucocyte, platelet, erythrocyte count and hemoglobin concentration in the experimental group and control group decreased progressively compared with the normal group. The most obvious decrease occurred on day 7. The trilineage recovered on day 14 after transplantation, basically returned to normal on day 21 after transplantation. Compared with the experimental group, the decrease of the trilineage in the control group was more obvious. The recovery was obvious faster in the experimental group than in the control group on day 14 after transplantation. Bone marrow smears: Bone marrow smears showed that the hematopoietic function was inhibited in the experimental group and the control group at 1, 5, 7, and 14 days after transplantation, especially on day 7. Bone marrow proliferation recovered on day 14 after transplantation. It was better in the experimental group than in the control group. On day 21 after transplantation, the hematopoietic function of bone marrow of mice in the experimental group and the control group recovered, and there was no difference between the experimental group and the control group compared with the normal group. Bone marrow pathological section: Bone marrow pathological sections showed that at 1, 5, 7, and 14 days after transplantation, the hematopoietic function of bone marrow in the experimental group and the control group was inhibited. On day 14 after transplantation, the bone marrow hematopoietic function of the experimental group and the control group began to recover, but the bone marrow proliferation of the experimental group was better than that of the control group. On day 21 after transplantation, there was no difference in the bone marrow proliferation between the experimental and the control groups and the normal group. The results suggested that human umbilical cord blood mesenchymal stem cells can promote the recovery of hematopoietic function of bone marrow.