Effects of cell culture time and cytokines on migration of dental pulp stem cell-derived chondrogenic cells in collagen hydrogels.

The transplantation of collagen hydrogels encapsulating human dental pulp stem cell (DPSC)-derived chondrogenic cells is potentially a novel approach for the regeneration of degenerated nucleus pulposus (NP) and cartilage. Grafted cell migration allows cells to disperse in the hydrogels and the treated tissue from the grafted location. We previously reported the cell migration in type I and type II hydrogels. It is important to explore further how cell culture time affect the cell motility. In this study, we observed the decreased motility of DPSC-derived chondrogenic cells after culturing for 2 weeks compared with cells cultured for 2 days in these gels. The Alamarblue assay showed the cell proliferation during the two-week cell culture period. The findings suggest that the transitions of cell motility and proliferation during the longer culture time. The result indicates that the early culture stage is an optimal time for cell transplantation. In a degenerated disc, the expression of IL-1β and TNFα increased significantly compared with healthy tissue and therefore may affect grafted cell migration. The incorporation of IL-1β and TNFα into the collagen hydrogels decreased cell motility. The study indicates that the control of IL-1β and TNFα production may help to maintain cell motility after transplantation.