Molecular Mechanism Of Adipose Tissue-derived Mesenchymal Stem Cells Differentiating Into A Nucleus Pulposus-like Phenotype

【Objective】To investigate the mechanism of adipose-derived mesenchymal stem cells which derive from female SD rat differentiating into nucleus pulposus-like phenotype, so as to lay a foundation for the cell transplantation therapy of intervertebral discs degeneration.【Methods】Rat ADSCs were isolated from the subcutaneous inguinal and perirenal region, purified using the method of limited dilution. Rat NP cells were cultured using tissue culturing method. The cell surface markers(Sca-1, CD44, CD45, CD11b) of ADSCs were examined by Fluorescence Activated Cell Sorter(FASC). To induce ADSCs towards a nucleus pulposus-like phenotype, ADSCs were cultured in 6-well culture plate with nucleus pulposus cells cocultured in a BD Falcon Cell Culture Insert. RNA expression of selected genes were then evaluated after 2 weeks′coculture.【Results】The results of flow cytometry showed that ADSCs were positive for Sca-1 and CD44, negative for CD11b and CD45. The outcome of RT-PCR showed that the gene expression of aggrecan, collagen type II and Sox-9, which were chondrocyte specific, were upregulated in ADSCs coculcured with NP cells. Also, the gene expression of Smad3 and Smad4 was higher than that of control groups. The fluorescence intensity of experimental groups is higher than control groups.【Conclusions】ADSCs can be directed towards the NP cell-like phenotype by coculturing with NP cells.