Study on Biological Characteristics of Cultured Rhesus Mesenchymal Stem Cells

This study was aimed to isolate and culture rhesus mesenchymal stem cells (MSC), and to analyze its phenotype and biological characteristics. Bone marrow was aspirated from femur of rhesus, mononuclear cells were extracted, the nonadherent cells were removed after 24 hours, adherent cells were subcultured when they grew 80% confluence. After the fifth passage, the cells were used for examination. The phenotypes of MSC were analyzed by flow cytometry, differentiated cells were identified by relevant specific staining. Cytokines' mRNA expressed by MSC were detected by RT-PCR. The results showed that rhesus MSC gave rise to a population of adherent cells characterized by the presence of a predominant cell type with a typical fibroblast-like morphology. During the log phase of growth, MSC proliferated to a two-fold population at 31-40 hours. MSC could be ex vivo expanded by successive cycles of trypsinization, seeding, and culture. The phenotypes expressed on rhesus MSC were Flk-1,CD29, CD105, CD166 positive and CD34, CD45,CD33 nearly negative. In various induction differentiation conditions, rhesus MSC could differentiate into the osteoblast and lipocyte. IL-6, TGF-β were highly expressed,TNF-α was lowly expressed and IL-2, Fas-L, IFN-γ were not detected on rhesus MSC using RT-PCR method. It is concluded that rhesus MSC can be successfully isolated and culture-expanded and the biological characteristics of rhesus MSC are similar to those of human MSC.