To find a new source of seed cells for constructing tissue-engineered intervertebral disc, nucleus pulposus (NP) cells and mesenchymal stem cells (MSCs) were isolated from New Zealand white rabbits. The nucleus pulposus cells population was fluorescence-laelled and co-cultured with MSCs with or without direct contact. Morphological changes were observed every 12 h. Semi-quantitative reverse transcriptase-polymerase chain reaction was performed to assess the expression levels of Sox-9, aggreacan and type II collagen every 24 h after the co-culture. MSCs treated with direct contact rounded up and presented a ring-like appearance. The expression of marker genes was significantly increased when cells were co-cultured with direct contact for 24 h. No significant change was found after coculture without direct contact. Co-culture of NP cells and MSCs with direct contact is a reliable method for generating large amount of NP cells used for cell-based tissue engineering therapy.
Aggrecans/metabolism ; Cell Differentiation ; Cells, Cultured ; Coculture Techniques ; Collagen/metabolism ; Gene Expression ; Gene Expression Regulation ; High Mobility Group Proteins/metabolism ; Intervertebral Disk/*cytology ; Mesenchymal Stem Cells/*cytology ; Mesenchymal Stem Cells/metabolism ; Models, Biological ; Reverse Transcriptase Polymerase Chain Reaction ; SOX9 Transcription Factor ; Tissue Engineering/instrumentation ; Tissue Engineering/*methods ; Transcription Factors/metabolism