Five side populations isolated from rat bone marrow‑derived mesenchymal stem cells

Abstract

Over the past decade, there has been marked enthusiasm surrounding the potential application of mesenchymal stem cells (MSCs) as universally compatible donor cells in the field of regenerative medicine. Due to their distinctive immune‑tolerant characteristics, these entities hold promise for potential applications in cell replacement, gene therapy and immunomodulatory therapy. MSCs have been defined and characterized based on adhesion properties and different surface markers that are negative for hematopoietic stem cells and positive for MSCs, and their capacity for differentiation into osteocyte, chondrocyte and adipocyte is observed under suitable circumstances. However, this protocol is costly and time‑consuming and cannot confirm the homogeneity of the isolated population of stem cells. Since no unique cell surface marker for prospective MSC isolation has yet been reported, at least to the best of our knowledge, the study, evaluation and characterization of MSCs greatly depend on their capacity to attach to, and subsequently undergo proliferation on a plastic surface. In the present study, MSCs were isolated from rat bone marrow, and these cells were divided into five groups according to their morphology, colony formation and proliferation rate. The expression levels of four pluripotency genes responsible for the differentiation, proliferation and self‑renewal of MSCs were examined in each group with the aim of identifying an alternative protocol for stem cell characterization which can be used instead of the current protocols (trilineage differentiation and flow cytometry), which are costly and time‑consuming. The molecular characterization of the MSCs revealed different expression levels of each gene, suggesting that the adherence isolation protocol led to the isolation of heterogenous populations that had different molecular patterns.