【目的】研究机体中枢神经系统受放射损伤时骨髓间充质干细胞(MSCs)的迁徙定植特性的改变,从而为应用MSCs治疗中枢神经系统放射损伤提供理论和实验依据。【方法】用8周龄SD大鼠接受22GyX线照射制作枢神经系统放射损伤模型;从GFP鼠抽取骨髓,分离和扩增MSCs。中枢神经系统受放射损伤的SD大鼠4个月后予静脉输注GFP-MSCs。于移植后几个时间点取脑、骨髓、肝、脾等做冰冻切片,用双光子共聚焦红外脉冲激光显微镜检测GFP-MSCs。【结果】在最早24h内实验组和对照组的骨髓中检测到外源性GFP阳性细胞,至第7天后实验组骨髓中GFP阳性细胞显著多于对照组。脑内第1天未检测到外源性GFP阳性细胞,第4天后中枢神经系统受放射损伤的SD大鼠,脑组织检测到带绿色荧光的外源性GFP阳性细胞;而对照组脑内一直未检测到带绿色荧光的外源性MSCs。实验组和对照组脾脏在输注MSCs后第1天即检测到大量GFP阳性细胞,并持续存在,第21天实验组GFP阳性细胞较对照组减少。【结论】在放射损伤条件下外源性MSCs可透过血脑屏障到达脑组织,中枢神经系统放射损伤可诱导外源性MSCs向脑组织迁徙定植。 【Objective】 To investigate the migration and colonization characteristics of bone marrow mesenchymal stem cells (MSCs) in the central nervous system under radiation injury, and to provide theoretical and experimental evidence for the application of MSCs in the treatment of central nervous system radiation injury. 【Methods】 Radiosensitization model of the central nervous system (CNS) was established by irradiation of 22Gy line of 8-week-old SD rats. MSCs were isolated and expanded from GFP mice. Four-month-old GFP-MSCs were infused intravenously in SD rats injured by radiation in the central nervous system. At several time points after transplantation, the brain, bone marrow, liver, spleen and other frozen sections were taken and GFP-MSCs were detected by two-photon confocal infrared pulse laser scanning microscope. 【Results】 Exogenous GFP-positive cells were detected in the bone marrow of the experimental group and the control group in the first 24 hours. The number of GFP-positive cells in the bone marrow of the experimental group was significantly more than that of the control group after the 7th day. Exogenous GFP-positive cells were not detected on the first day in the brain, and exogenous GFP-positive cells with green fluorescence were detected in the brain of SD rats injured by radiation in the central nervous system after 4 days. In the control group, Exogenous MSCs with green fluorescence were not detected. A large number of GFP-positive cells were detected in the spleen of the experimental group and the control group on the first day after the MSCs were transfused, and the number of GFP-positive cells in the experimental group decreased on the 21st day. 【Conclusion】 Exogenous MSCs can reach the brain tissue through the blood-brain barrier under the condition of radiation injury. Radiation injury of the central nervous system can induce the migration of exogenous MSCs to brain tissue.