[In vitro tracing of rat bone marrow mesenchymal stem cells using the fluorescent dye CFSE].

OBJECTIVE: To determine the optimal condition for labeling rat mesenchymal stem cells (MSCs) using the fluorescent dye CFSE and the maximum time length allowed by CFSE staining for MSC tracing in vitro. METHODS: Rat MSCs were labeled with CFSE at different concentrations (2.5, 5.0, 10.0, 20.0 and 40.0 micromol/L) for 1, 5 or 10 min. The transfection efficiency and fluorescence intensity in the cells were measured by flow cytometry and fluorescence microscope to determine the optimal condition for MSC labeling. Under the optimal condition, the effect of CFSE on the growth of MSCs was evaluated by MTT assay, and flow cytometry and fluorescence microscope were used to determine the maximum time length following CFSE labeling to allow MSC tracing. RESULT AND CONCLUSION: Staining with CFSE at 20.0 micromol/L for 5 min was optimal for labeling rat MSCs in vitro, which allowed detection of the MSCs as long as 21 days after the labeling without obviously affecting the cell growth (P>0.05).