Cheng Jing-liang, Yang Yun-jun, Li Hua-li, Wang Juan, Wang Mei-hao, Zhang Yong
Department of Radiology, First Affiliated Hospital, Zhengzhou University, China.
Chin J Traumatol. 2010 Jun 1;13(3):173-7.
To label rat bone marrow mesenchymal stem cells (BMSCs) with superparamagnetic iron oxide (SPIO) in vitro, and to monitor the survival and location of these labeled BMSCs in a rat model of traumatic brain injury (TBI) by susceptibility weighted imaging (SWI) sequence.
BMSCs were cultured in vitro and then labeled with SPIO. Totally 24 male Sprague Dawley (SD) rats weighing 200-250 g were randomly divided into 4 groups: Groups A-D (n equal to 6 for each group). Moderate TBI models of all the rats were developed in the left hemisphere following Feeney's method. Group A was the experimental group and stereotaxic transplantation of BMSCs labeled with SPIO into the region nearby the contusion was conducted in this group 24 hours after TBI modeling. The other three groups were control groups with transplantation of SPIO, unlabeled BMSCs and injection of nutrient solution respectively conducted in Groups B, C and D at the same time. Monitoring of these SPIO-labeled BMSCs by SWI was performed one day, one week and three weeks after implantation.
Numerous BMSCs were successfully labeled with SPIO. They were positive for Prussian blue staining and intracytoplasm positive blue stained particles were found under a microscope (200). Scattered little iron particles were observed in the vesicles by electron microscopy (5000). MRI of the transplantation sites of the left hemisphere demonstrated a low signal intensity on magnitude images, phase images and SWI images for all the test rats in Group A, and the lesion in the left parietal cortex demonstrated a semicircular low intensity on SWI images, which clearly showed the distribution and migration of BMSCs in the first and third weeks. For Group B, a low signal intensity by MRI was only observed on the first day but undetected during the following examination. No signals were observed in Groups C and D at any time points.
SWI sequence in vivo can consecutively and noninvasively trace and demonstrate the status and distribution of BMSCs labeled with SPIO in the brain of TBI model rats.
体外使用超顺磁性氧化铁（SPIO）标记大鼠骨髓间充质干细胞（BMSCs），并通过磁敏感加权成像（SWI）序列监测这些标记的BMSCs在创伤性脑损伤（TBI）大鼠模型中的存活及定位情况。
体外培养BMSCs，然后用SPIO进行标记。将24只体重200 - 250 g的雄性Sprague Dawley（SD）大鼠随机分为4组：A - D组（每组n = 6）。按照Feeney法在所有大鼠左半球建立中度TBI模型。A组为实验组，在TBI建模后24小时将经SPIO标记的BMSCs立体定向移植到挫伤灶附近区域。其他三组为对照组，B、C、D组分别在同一时间进行SPIO移植、未标记的BMSCs移植和注射营养液。移植后1天、1周和3周通过SWI对这些经SPIO标记的BMSCs进行监测。
大量BMSCs成功被SPIO标记。普鲁士蓝染色呈阳性，显微镜下（200倍）可见胞质内有蓝色阳性染色颗粒。电子显微镜下（5000倍）在囊泡中观察到散在的少量铁颗粒。A组所有受试大鼠左半球移植部位的MRI在幅度图像、相位图像和SWI图像上均显示低信号强度，左侧顶叶皮质病变在SWI图像上呈半圆形低信号，清晰显示了第1周和第3周BMSCs的分布和迁移情况。B组MRI仅在第1天观察到低信号强度，后续检查未检测到。C组和D组在任何时间点均未观察到信号。
体内SWI序列可连续、无创地追踪并显示TBI模型大鼠脑中经SPIO标记的BMSCs的状态和分布。
