Scharf Alexandra, Holmes Shannon, Thoresen Merrilee, Mumaw Jennifer, Stumpf Alaina, Peroni John
Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, H-322, Athens, GA, 30602, USA.
Department of Biological and Agricultural Engineering, College of Engineering, University of Georgia, Athens, GA, 30602, USA.
Contrast Media Mol Imaging. 2015 Sep-Oct;10(5):388-97. doi: 10.1002/cmmi.1642. Epub 2015 Jun 1.
The goal of this study was to establish an SPIO-based cell-tracking method in an ovine model of tendonitis and to determine if this method may be useful for further study of cellular therapies in tendonitis in vivo. Functional assays were performed on labeled and unlabeled cells to ensure that no significant changes were induced by intracellular SPIOs. Following biosafety validation, tendon lesions were mechanically (n = 4) or chemically (n = 4) induced in four sheep and scanned ex vivo at 7 and 14 days to determine the presence and distribution of intralesional cells. Ovine MSCs labeled with 50 µg SPIOs/mL remained viable, proliferate, and undergo tri-lineage differentiation (p < 0.05). Labeled ovine MSCs remained detectable in vitro in concentrated cell numbers as low as 10 000 and in volumetric distributions as low as 100 000 cells/mL. Cells remained detectable by MRI at 7 days, as confirmed by correlative histology for dually labeled SPIO+/GFP+ cells. Histological evidence at 14 days suggested that SPIO particles remained embedded in tissue, providing MRI signal, although cells were no longer present. SPIO labeling has proven to be an effective method for cell tracking for a large animal model of tendon injury for up to 7 days post-injection. The data obtained in this study justify further investigation into the effects of MSC survival and migration on overall tendon healing and tissue regeneration.
本研究的目的是在绵羊肌腱炎模型中建立基于超顺磁性氧化铁（SPIO）的细胞追踪方法，并确定该方法是否有助于体内肌腱炎细胞治疗的进一步研究。对标记和未标记的细胞进行功能测定，以确保细胞内SPIO不会引起显著变化。在生物安全性验证后，对四只绵羊进行机械（n = 4）或化学（n = 4）诱导肌腱损伤，并在第7天和第14天进行离体扫描，以确定损伤部位细胞的存在和分布。用50μg SPIO/mL标记的绵羊间充质干细胞（MSC）保持存活、增殖并进行三系分化（p < 0.05）。标记的绵羊MSC在体外低至10000个细胞的浓缩细胞数以及低至100000个细胞/mL的体积分布中仍可检测到。如双标记SPIO+/GFP+细胞的相关组织学所证实，在第7天时通过磁共振成像（MRI）仍可检测到细胞。第14天的组织学证据表明，尽管细胞已不存在，但SPIO颗粒仍嵌入组织中，提供MRI信号。已证明SPIO标记是一种在注射后长达7天的大型动物肌腱损伤模型中进行细胞追踪的有效方法。本研究获得的数据为进一步研究MSC存活和迁移对整体肌腱愈合和组织再生的影响提供了依据。
