Abstract. Mesenchymal stem cell (MSC) transplantation provides a novel strategy for the treatment of human disease. MR imaging (MRI) is able to track transplanted stem cells labeled with superparamagnetic iron oxide (SPIO) in vivo. However, the effect of SPIO upon labeled MSCs remains unclear on a cellular level. In this study, the biological characteristics of rat MSCs labeled with home-synthesized SPIO particles were evaluated. The MSCs were isolated from the bone marrow of 5 adult Sprague-Dawley rats and labeled with home-synthesized SPIO particles at a final iron concentration of 20 µg/ml. Labeled MSCs were confirmed with Prussian blue staining and transmission electron microscopy. The quantity of iron per cell was determined by atomic absorption spectrometry. Cell viability, proliferation, membranous antigen and multiple differentiation ability were compared between labeled and unlabeled MSCs. The rat MSCs were effectively labeled and the labeling efficiency was approximately 100%, as revealed by Prussian blue staining. The SPIO particles located in the endosomal vesicles of the MSCs were confirmed by transmission electron microscopy. No significant differences were observed in cell viability, proliferation, membranous antigen and multiple differentiation ability between the labeled and unlabeled MSCs (P>0.05). In conclusion, MSCs are able to be effectively labeled by home-synthesized SPIO particles without influencing their main biological characteristics.
IntroductionAs a potential interventional procedure, stem cell transplantation provides a new strategy for the treatment of incurable human diseases and organ failure (1-3). The plasticity of bone marrow mesenchymal stem cells (MSCs) has been intensively investigated, since this approach generates less ethical and social controversies. The use of bone marrow MSCs also offers several advantages, including ease of collection and rapid in vivo and in vitro repopulation. Numerous studies have shown that MSCs are capable of forming functional components of organ tissues, including the kidney, heart and liver (1-4).A non-invasive in vivo technique that permits evaluation of the efficiency of transplantation and the potential migration of transplanted cells would prove to be an essential tool for treatment assessment. To better understand the mechanisms of the cell therapy, in vivo monitoring of the cellular dynamics of the transplanted MSCs has been proposed. Recently, MR imaging (MRI) has proven to be effective in tracking the distribution of transplanted MSCs in vivo by way of labeling cells with superparamagnetic iron oxide (SPIO) particles (5-7).However, it is not clear whether the SPIO labeling technique of MSCs is safe. Additionally, the effect of SPIO upon labeled cells remains unclear on a cellular level (8). Thus, the purpose of the present study was to investigate whether and how the labeling of MSCs with SPIO affects the biological characteristics of MSCs.
Materials and methodsCell culture. This study was approved by our institutional Animal Use and...