Dunning Mark D, Kettunen Mikko I, Ffrench Constant Charles, Franklin Robin J M, Brindle Kevin M
Cambridge Centre for Brain Repair, University of Cambridge, Cambridge CB2 2PY, UK.
Neuroimage. 2006 May 15;31(1):172-80. doi: 10.1016/j.neuroimage.2005.11.050. Epub 2006 Jan 25.
There is increasing interest in the use of magnetic resonance imaging (MRI) methods for tracking the fate of labelled cells in vivo post-implantation. The majority of studies have employed cell labels based on nanometer-sized ultrasmall dextran-coated iron oxide particles (USPIO), which are detected through signal hypointensity in T2-weighted images. Although sensitive to MR detection, these labels can be difficult to distinguish from other sources of signal loss in vivo and can be diluted by cell division. Recently, a micron-sized cell label has been described that is much more sensitive to MR detection and which allows detection of single labels in vivo. We show here that glial cells readily take up this label in culture and that the labelled Schwann cells can be detected in vivo by MRI following their implantation into a demyelinated lesion in the rat spinal cord. Signal loss due to the label is sufficiently great that the labelled cells can easily be distinguished from surrounding haemorrhage at the lesion site. Subsequent histological analysis of the lesion area showed that the transplanted cells were remyelinating the demyelinated axons, demonstrating that the labelled cells retained their biological function and that the majority of the label had remained within the transplanted cells.
利用磁共振成像（MRI）方法追踪植入后体内标记细胞的命运越来越受到关注。大多数研究采用基于纳米级超小葡聚糖包被氧化铁颗粒（USPIO）的细胞标记物，这些标记物通过T2加权图像中的信号低强度来检测。尽管对磁共振检测敏感，但这些标记物在体内可能难以与其他信号损失源区分开来，并且可能会因细胞分裂而稀释。最近，有人描述了一种微米级细胞标记物，它对磁共振检测更为敏感，能够在体内检测到单个标记物。我们在此表明，胶质细胞在培养中很容易摄取这种标记物，并且将标记的雪旺细胞植入大鼠脊髓的脱髓鞘病变后，可通过MRI在体内检测到它们。由于标记物导致的信号损失足够大，以至于标记的细胞能够很容易地与病变部位周围的出血区分开来。随后对病变区域进行的组织学分析表明，移植的细胞正在对脱髓鞘轴突进行重新髓鞘化，这表明标记的细胞保留了它们的生物学功能，并且大部分标记物仍留在移植细胞内。
