In Vitro Study On Interaction Between Adipose Tissue-derived Mesenchymal Stem Cells And Nucleus Pulposus Cells Through Paracrine Stimulation

Objective Co-culture adipose tissue-derived mesenchymal stem cells (AMSCs )and autologous nucleus pulposus(NP) cells without direct contacting under hypoxia. To investigate the interaction between NP cells and AMSCs through paracrine stimulation.Methodsâ‘ Rat AMSCs were isolated from the subcutaneous inguinal region only, purified by limited dilution.â‘¡AMSCs of the third passage were analyzed by Fluorescence Activated Cell Sorter (FASC) to detect the cell surface markers.â‘¢Co-culture AMSCs and degenerative NP cells without direct contacting in different ratios under hypoxia.â‘£Two weeks later, NP cells proliferation and RNA expression of selected genes were then evaluated after co-cultured; immunohistochemical analysis and RNA expression were used to detect AMSCs after induced.Resultsâ‘ Proliferation of NP cells significantly rose even after cocultured with a few AMSCs. The biologic and metabolic viability of NP cells were upregulated, the results of RT-PCR manifested that there was significant difference in gene expression of aggrecan and collagen II among two groups (P<0.01). Immunohistochemical analysis showed that AMSCs started to express collagen II, the results of RT-PCR demonstrated that the gene expression of HIF-alpha, Sox-9, aggrecan and collagen type II, which were chondrocyte specific, were upregulated. There was significant difference in gene expression (P<0.01).Conclusions The results showed a possible mechanism of interaction between AMSCs and NP cells mediated by secreted factors:â‘ NP cells promoted AMSCs differentiated into nucleus pulposus-like cells, the differentiate ratios was depended on the number of NP cells.â‘¡Proliferation of NP cells significantly rose even after cocultured with a few AMSCs. The biologic and metabolic viability of NP cells were upregulated.