Immunophenotype characterization of rat mesenchymal stromal cells

Background Mesenchymal stromal cells (MSC) have shown diverse therapeutic potential. While characterization of human and mouse MSC has seen significant advances, rat bone marrow-derived MSC (rBM-MSC) remain under-characterized. We detail the isolation, expansion, differentiation, and detailed immunocharacterization of rBM-MSC. Methods Rat MSC were isolated and expanded in multipotent adult progenitor cell (MAPC) media, and cell-surface marker expression through 10 passages was used to characterize the population and multipotency was confirmed via differentiation. Results By passage 3, rBM-MSC were found to be CD11b− , CD45− , CD29+ , CD49e+ , CD73+ , CD90+ , CD105+ and Stro-1+ , without the use of cell sorting. Media selection was responsible for the isolation of a nearly homogeneous population of rBM-MSC. The rBM-MSC immunophenotype changed by passage 10, showing decreases in CD73, CD105 and Stro-1 expression. Discussion Detailed characterization of cell populations facilitates accurate and reproducible cell therapy investigation. Given the expanding body of research involving rBM-MSC, these results advance our ability to compare rBM-MSC populations.