The Tracking Study Of MRI After Transplanttation Of Bone Marrow Stromal Cells Labeled By Superparamagnetic Iron Oxide In Vivo In Rat Parkinson's Disease Models

In this study,we made administration of labeling bone marrow stromal cells(BMSCs) with superparamagnetic iron oxide ( SPIO),and track labeled cells with 1.5Tesla 47mm inner diameter micro-coil in vitro and in vivo after implantation.To explorethe feasibility of labeling BMSCs with SPIO in vitro and to monitor the labeled cells aftertransplantation into the PD rats with MRI scanning .The study was divided into two parts:Objective: To label BMSCs with SPIO and study the relaxivity of labeled cells withMRI in vitro.Identify the best sequences and numbers of label BMSCs for MRI scaning ,and as abasis for the next part.Methods:BMSCs were labeled with SPIO mediated by PLL(poly-l-lysine).Prussianblue staining was conducted to identify the iron particles in these BMSCs.The subjectswere divided into seven groups,including 1×10 labeled cells,5×10~5 labeled cells,6×10~6labeled cells,1×10~5 unlabeled cells,5×10~5 unlabeled cells,6×10~6 unlabeled cells andagarose .MRI scanning sequences included TSE-T1WI,TSE- T2WI,FFE-T2WI .Signalintensity of labeled cells were calculated and compared with unlabeled cells.Results :BMSCs could be labeled with SPIO and labeling efficiency was 100% .Prussian blue staining showed numerous blue stained iron particles in the cytoplasm.Thesignal intensity had significant difference between labeled cells however there was nosignificant difference between the results in unlabeled cells ,the signal intensities of labeledcells were changed to varying degrees with different sequences and the most significantchange occurred in FFE-T2WI sequence.Conclusion :SPIO can be used to label BMSCs effectively ;MRI can be used to track labeled cells in vitro and FFE-T2WI sequence was the most sensitive sequences fordetecting the SPIO-labeled BMSCs.The signal intensity of subjects changed dependant onthe numbers of SPIO-labeled BMSCs.Objective:To explore the feasibility of labeling BMSCs with SPIO(Feridex) and tomonitor the labeled cells after transplantation into the PD rats with 1.5T MRI 47mm innerdiameter micro-coil scanning.Methods:30 PD rats were andomly divided into four groups,including direct injectionwere transplanted labeled cells,direct injection were transplanted unlabeled cells ,intravenousinjection were transplanted with labeled cells and intravenous injection were transplanted withunlabeled cells .In vivo MRI exam ination was conducted on rat brains at first day and2,4,6 and 8 weeks after transplanted .After MR imaging,two rats of each group werekilled and Prussian blue staining and immunofluorescent staining of the histologicalsections were performed.Results:In vivo tracking magnetic resonance images showed that darks signalappeared in the transplanted area in direcd injecttion method ;brain patho-tissue alsoshowed that SPIO labeled BMSCs .In vivo tracking magnetic resonance images showedno dark signal appeared in PD brain in intravenous injection ;but brain patho- tissuesshowed a few SPIO labeled BMSCs in brain of PD rats.Conclusion:1.5T MRI 47mm inner diameter micro-coil tracking in vivo was apromising method for direcd injecttion with BMSCs labeled by SPIO however it was aunpromising method for intravenous injection with BMSCs labeled by SPIO.