Treatments for intervertebral discs degeneration by stem cells transplantation : a therapeutic potential comparison between bone marrow stem cells and adipose-derived stem cells

Objective: The aim of this study was to compare the therapeutic effects between the transplanted bone mesenchymal stem cells (BMSCs) and adipose-derived stem cells (ADSCs) in rabbits by using a degenerative disc model. Methods: Firstly, the intervertebral discs degeneration animal model was constructed by the conventional punctured method. Then, BMSCs and ADSCs were transplanted into the rabbit’s model of disc degeneration, respectively. The nucleus pulposus cells (NPCs) transplantation group was set as the positive group, only Dulbecco’s modified Eagle’s medium (DMEM) injection group was set as the negative group and the health intervertebral disc group was set as the normal control (NC) group. The samples were harvested in 12 weeks after the transplantation. Disc degeneration degree was evaluated by plain radiography as well as the MRI imaging T2-weighted signal intensity, histology, sulfated glycosaminoglycan (sGAG)/DNA, immunochemical staining. Also, the gene expression levels of collagen II and aggrecan were evaluated. Results: Twelve weeks after cell-transplantation, the degeneration degree for the DMEM group was significantly higher than the other four groups (P<0.05). Histological analysis indicated no significant difference among NPCs, BMSCs and ADSCs groups, while the other results, including disc height index ratio (%DHI), standard T2-weighted image ratio (%ST2WI), sGAG/DNA assessment and mRNA expression levels of the aggrecan, showed that the therapeutic effects of NPCs and BMSCs groups were much better than that of the ADSCs group. While no significant differences between the NPCs and BMSCs groups were found. Conclusion: The results indicated that all types of cells in this study had a positive effect on restraining the discs degeneration. Especially, BMSCs showed a stronger potential in the extracellular matrix synthesis and water content recovery of the discs, similar to that of NPCs. The BMSCs transplantation was more effective in the disc degeneration treatment than ADSCs, which appears to be an ideal substitute for NPCs.