活体示踪BMSCs在大鼠癫痫模型中的可行性研究

Feasibility of tracking bone marrow mesenchymal stem cells in a rat model of epilepsy

目的探索活体示踪骨髓间充质干细胞(BMSCs)在大鼠癫痫模型中的可行性。方法体外分离纯化SD大鼠BMSCs,超微超顺磁性氧化铁(USPIO)纳米颗粒标记,而后诱导大鼠癫痫模型并接受USPIO标记的BMSCs(U-BMSCs)移植,进而通过MRI检测U-BMSCs体内外影像,示踪UBMSCs在癫痫模型中的分布,最后通过免疫组化验证USPIO标记对BMSCs抑制癫痫海马神经元损失的影响。结果 USPIO体外标记BMSCs的效率为99.2%±1.24%,体内外MRI T2W2显示U-BMSCs为可与脑实质区别明显的低信号影像。细胞移植两周后发现U-BMSCs低信号影像可分布于癫痫模型脑实质包括海马,免疫组化结果示U-BMSCs移植组海马CA1和齿状回门区(DH)神经元数量明显多于PBS组(P<0.05),且与BMSCs移植组无明显区别(P>0.05)。结论 USPIO标记BMSCs可依赖MRI检测实现其在大鼠癫痫模型中的活体示踪且不影响其神经保护功能。

Objective The feasibility of real time tracking of bone marrow mesenchymal stem cells （BMSCs） in a rat model of epilepsy is explored. Methods BMSCs were isolated from 4 SD rats and labeled with ultrasmall superparamagnetic iron oxide （USPIO） nanoparticles, and then the epileptic models were induced by Pilocarpine and received USPIO labeled BMSCs （U-BMSCs） administration. After that, MRI was performed to detect the U-BMSCs imaging in vitro and in vivo, as well as the distribution of U- BMSCs in a rat model of epilepsy. Finally, the neuroprotection of U-BMSCs on the epilepsy-induced hippocampal neuronal loss was verified by immunohistochemistry. Results Prussian blue staining results showed the uptaken efficiency of USPIO in BMSCs was 99.20% ＋ 1.24%. In vitro study manifested that U- BMSCs displayed as darker signal in MRI T2W2, and in vivo study showed that the darker signal distinguished from brain or eerebrospinal fluid imaging was observed in the right lateral after U-BMSCs transplantation for 24 h. After cell transplantation for 2 w, the darker signals of U-BMSCs were observed in the cortex, hippoeampus and other areas of the brain. Furthermore, immunohistochemistry results showed that U-BMSCs transplantation prevented the neuronal loss in CA1 and dentate gyrus hilus （ DH ） of the hippocampus in comparison to PBS group （ P 〈 0.01 ）, and no significant difference （ P 〉 0.05 ） was shown between U-BMSCs and BMSCs transplantation in the epileptic model. Conclusion USPIO labeling BMSCs can be detected in vivo using MRI and do not affect their neuroproteetion in a rat model of epilepsy.