Differentiation of Menstrual Blood-Derived Stem Cells Toward Nucleus Pulposus-Like Cells in a Coculture System With Nucleus Pulposus Cells

Study Design. Human stromal stem cells derived from menstrual blood (MenSCs) and nucleus pulposus (NP) cells were cocultured under normal or low oxygen (O-2) condition. Objective. To assess the differentiation capability of MenSCs toward nucleus pulposus cells under normal or low oxygen condition. Summary of Background Data. Given the proliferative capacity and pluripotentiality of mesenchymal stem cells, mesenchymal stem cells transplantation is thought to be a promising approach to managing intervertebral disc degeneration. Methods. Using coculture plates with 0.4-mu m pore size polyethylene terephthalate track-etched inserts, MenSCs and NP cells (1: 1 ratio) were cocultured with cell-to-cell contact for 2 weeks in normal (20% O-2) or low oxygen tension (2% O-2), respectively. Extracellular matrix accumulation was quantified by dimethylmethylene blue assay, histological staining, and quantitative reverse-transcription polymerase chain reaction. Novel characteristic human NP markers cytokeratin-19 (KRT19), carbonic anhydrase XII (CA12), and forkhead box F1 (FoxF1) were also detected by quantitative reverse-transcription polymerase chain reaction. Results. The result of quantitative reverse-transcription polymerase chain reaction showed that aggrecan and COL2A1 genes expression was significantly increased in differentiated MenSCs (P < 0.05). There was significantly more COL2A1 gene expression in normoxic group than that in low O-2 group (P < 0.05). But no significant difference was observed in aggrecan gene expression between normoxic group and low O-2 group. These aforementioned results were also confirmed by histological analysis. We also found that the characteristic NP markers (KRT19, CA12, FoxF1) were significantly upregulated in differentiated MenSCs. Moreover, low O-2 tension (2%) further enhanced these genes expression (P < 0.05). Conclusion. In our study, MenSCs were successfully differentiated into NP-like cells and may become a new source of seed cells for the treatment of intervertebral disc degeneration in the future.