Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.
NMR Biomed. 2012 Apr;25(4):620-31. doi: 10.1002/nbm.1778. Epub 2011 Aug 26.
The purpose of the present study was to use magnetic resonance imaging (MRI) as a tool for monitoring transplant-mediated repair of the adult rat visual pathway. We labelled rat olfactory ensheathing cells (OECs) using micron-sized particles of iron oxide (MPIO) and transplanted them by: i) intravitreal injection (ivit) and ii) intra-optic nerve (ON) injection (iON) in adult rats with ON crush (ONC) injury. We applied T(2)-weighted MRI and manganese-enhanced MRI (MEMRI) to visualise transplanted cells and ON axons at specific times after injury and cell engraftment. Our findings demonstrate that ivit MPIO-labelled OECs are unequivocally detected by T(2)-weighted MRI in vivo and that the T(1)-weighted 3D FLASH sequence applied for MEMRI facilitates simultaneous visualisation of Mn(2+-) enhanced regenerating retinal ganglion cell (RGC) axons and MPIO-labelled OEC grafts. Furthermore, analysis of MRI data and ultrastructural findings supports the hypothesis that iON OEC transplants mediate regeneration and remyelination of RGC axons post injury.
本研究旨在利用磁共振成像（MRI）作为监测成年大鼠视觉通路移植介导修复的工具。我们使用微米级氧化铁颗粒（MPIO）标记大鼠嗅鞘细胞（OEC），并通过以下两种方法进行移植：i）玻璃体内注射（ivit）和 ii）视神经内注射（iON），将其移植到视神经挤压（ONC）损伤的成年大鼠中。我们应用 T2 加权 MRI 和锰增强 MRI（MEMRI）在损伤和细胞移植后特定时间观察移植细胞和视神经轴突。我们的研究结果表明，ivit MPIO 标记的 OEC 可以通过体内 T2 加权 MRI 明确检测到，并且应用于 MEMRI 的 T1 加权 3D FLASH 序列有利于同时观察 Mn（2+）增强的再生视网膜神经节细胞（RGC）轴突和 MPIO 标记的 OEC 移植物。此外，MRI 数据和超微结构分析支持这样的假设，即 iON OEC 移植介导了损伤后 RGC 轴突的再生和髓鞘形成。
