The effect of injecting bone mesenchymal stem cells into nucleus pulposus on the biochemistry of intervertebral disc

Objective: To explore the effect of injecting bone mesenchymal stem cells into nucleus pulposus on the biochemistry of intervertebral disc. Methods: Totally 32 rabbits were used, each of whose lumbar discs from the second to fifth were randomly divided into normal group, saline group, cell transplantation group I, and cell transplantation group K (group of the transferring gene coding BMP). At 1 month-, 3 month-, 6 month-time point after operation, immunohistochemistry was used to determine the change of phenotype of collagen, real time PCR was used to analyze the expression of collagen type I and II and proteoglycan, followed by repeated ANOVA used to analyze the data. Results: At 1 month-, 3 month-, 6 month-time point after operation, there were more cells in cell transplantation group than in normal group or saline group. Toludine blue staining showed that there was deeper blue in cell transplantation group than in normal group or saline group. Immunohistochemistry showed there was deeper red in cell transplantation group than in normal group or saline group in collagen type II, whereas there was no change in collagen I among the groups. Real time PCR showed that the expression of proteoglycan or collagen type II was increased in cell transplantation group whereas collagen type I remained unchanged among the groups. In addition, compared to that of cell transplantation group I, the expression of proteoglycan or collagen type II was increased in cell transplantation group II. Conclusion: The transplanted bone mesenchymal stem cells can increase the amount of proteoglycan or collagen type II; combined with the transfer of BMP₂, the effect is overlaying, suggesting that the therapeutic strategy based on bone mesenchymal stem cells may be effective in prevention and treatment of intervertebral disc degeneration.