300 ESTABLISHMENT AND CHARACTERIZATION OF RAT MESENCHYMAL STEM CELLS

Abstract

Mesenchymal stem cells (MSC) are regarded as an attractive source for tissue engineering and regeneration, and bone marrow extract has been commonly used as a source of pluripotent MSC. However, skin tissue has recently been identified as a convenient alternative source of MSC. The present study was focused on the effect of characterised MSC derived from rat on expression of early transcriptional factors, alkaline phosphate (AP) activity, and in vitro differentiation into selected cell lineages. The MSC were isolated from 8-week-old s.d. rat’s ear skin and cultured in advanced DMEM supplemented with 10% fetal bovine serum at 37°C in a humidified atmosphere of 5% CO₂ in air. To evaluate AP activity, cells were fixed with 3.7% formaldehyde solution and stained with Western Blue^® (Promega, Madison, WI, USA). Expressions of early transcriptional factors (Oct-4, Sox2, and Nanog) were evaluated by RT-PCR. Differentiation into distinct mesenchymal lineages such as adipogenic, osteogenic, and neuron was done by following previously described protocols and assessed by lineage-specific stains. The specific genes in the osteocytes (osteocalcin, osteonectin, osteopontin, and Runx2), adipocytes (pparγ2, adiponectin, and aP2) or neuron (nestin, neurogenin 1, β-tublin, and nerve growth factor) were characterised by RT-PCR. The MSC were positive for AP activity and expressed Oct-4, Sox2, and Nanog. Following induction, MSC were successfully differentiated into adipocytes, osteocytes, and neurons. As adipocytes markers, aP2, pparγ2, and adiponectin were strongly detected in the adipocyte induced cells. Osteonectin, osteocalcin, Runx2, and osteopontin were expressed in the adipocyte induced cells. Futhermore, neuron-specific markers were clearly expressed in the neuronal differentiated cells. In conclusion, MSC have the capability of differentiation into multilineages including adipocytes, osteocytes, and neurons under the specific induction conditions. Skin tissue in rat can serve as an easily accessible and expandable alternative source for MSC harvesting and preclinical applications using an animal model.