摘要BACKGROUND: Nowadays, it is becoming more and more important to optimize safety of human derived cel s, label cel s efficiently and track cel s after cel s transplantation both in basic research and clinic application.OBJECTIVE: To compare the cel viability, labeling efficiency and imaging effect of the T2* weight image (WI) magnetic resonance (MR) between the human bone marrow and umbilical cord derived mesenchymal stem cel s labeled with the superparamaganetic iron oxide nanoparticles, as wel as to optimize their treatment efficiency.METHODS: The third generation of human bone marrow and umbilical cord derived mesenchymal stem cel s were cultured, and labeled with 5-30 mg/L Feridex Ⅳ and protamine sulfate.RESULTS AND CONCLUSION: The viability of human bone marrow mesenchymal stromal cel s was similar with human umbilical cord derived mesenchymal stem cel s (P >0.05). There was no significant difference of labeling rate between the bone marrow msenchymal stem cel s labeled with 5-30 mg/L Feridex Ⅳ(P >0.05); while there was significant difference of labeling rate between the umbilical cord derived mesenchymal stem cel s labeled with 5 mg/L Feridex Ⅳ and 20 and 30 mg/L Feridex Ⅳ(P <0.05); the positive labeling rate of umbilical cord derived mesenchymal stem cel s was lower than that of bone marrow msenchymal stem cel s after labeled with 10 mg/L FeridexⅣ(P <0.05). When two sources of cel s were labeled with Feridex Ⅳ more than 2 mg/L, the iron oxide particles were found in the cel suspension and could not be removed by elution and filtration. The signal intensity from 3.0T MR GRE T2*WI scan was decreased with the increasing of Feridex Ⅳ concentration in both cel types. It is safe and effective to label the two tissue-derived mesenchymal stem cel s with 10 mg/L Feridex Ⅳ-protamine sulfate complex, and can be observed with T2*WI MR.