Gd-DTPA标记骨髓间质干细胞在脊髓损伤模型中的磁共振示踪研究

目的 探讨用钆-二乙烯三胺五乙酸(Gd-DTPA)标记大鼠骨髓间质干细胞(MSCs)用于细胞示踪的可行性.方法 用jetPEITM-FluoF结合Gd-DTPA形成顺磁性颗粒,标记MSCs,电镜观察标记情况,并用MTT法测定标记细胞的活力.对标记的细胞进行体外和大鼠脊髓内磁共振成像(MRI).结果 Gd-DTPA可高效标记MSCs,同时对MSCs生长无影响.体外及MSCs移植大鼠脊髓损伤模型MRI T1wI均显示,标记细胞呈高信号强度.结论 Gd-DTPA成功标记的MSCs在体外和大鼠脊髓组织内均可检测到明显的MRI信号强度改变.Gd-DTPA可以用于MSCs标记的MRI示踪.

Tracking of mesenchymal stem cells labeled with Gd-DTPA by MR imaging in spinal cord injury model

Objective The aim of the study was to explore the possibility of the rat Mesenchymal stem cells (MSCs) labeled with Gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) for cell tracking. Methods jetPEI^TM-FluoF, a cationic polymer transfection reagent, conjugated with Gd-DTPA to form magnetic particles, was used to label MSCs. Electron microscopy was performed to detect the distribution of Gd-DTPA particles in MSCs, and labeling efficiency of Gd-DTPA particles on MSCs was evaluated using immunofluorescence. Viability and proliferation of labeled MSCs were evaluated using MTT assay. Apoptosis of labeled MSCs were evaluated using Hochest 33342 staining. Labeled MSCs was detected with T1-weighed MR imaging in vitro and in rat spinal cord. Results Transmission electron microscopy confirmed the presence of Gd-DTPA particles inside the cells. Labeling efficiency was approximately no less than 80%. MTT values of light absorption were 0.1594±0.0084 for labeled MSCs and 0.1675±0.0063 for unlabelled MSCs after 24 hours post labeling, which had no significant difference (P>0.05). Hochest 33342 staining showed that labeling did not influence the apoptosis of MSCs. Labeled MSCs demonstrated a significant increase signal intensity on T1-weighed MRI in vitro, and the signal intensity of labeled MSCs increased by 26.61% compared with the around spinal cord tissues (P<0.05). Conclusion Rat MSCs could be labeled with Gd-DTPA particles without change the cell viability, proliferation and apoptosis. Obviously labeled MSCs can be imaged in vitro and in vivo in rat spinal cord tissues. Gd-DTPA shows no evident adverse effect on the function of labeled MSCs. Gd-DTPA can be used for the MR imaging tracking of labeled MSCs.