The Role of IL-6 in Osteogenic and Neurogenic Differentiation Potentials of Dental Pulp Stem Cells (DPSCs)

Introduction: Interleukin 6 (IL-6) is a pleiotropic soluble mediator which is involved with many different parts of inflammatory processes. Studies have shown that there is a significantly higher concentration of IL-6 in inflamed pulp tissues when compared to healthy pulp tissues. However, there are no comprehensive studies on how IL-6 can interact with dental pulp stem cells (DPSCs) from healthy (H-DPSCs) and inflamed pulp tissues (I-DPSCs) and how it can affect the differentiation potential of DPSCs. Therefore, I hypothesized that IL-6 can promote osteogenesis while inhibiting neurogenesis from DPSCs. The aims of this study were to investigate the baseline differences between the H-DPSCs and I-DPSCs, and determine how IL-6 can affect the osteogenic and neurogenic differentiation potentials of DPSCs. Materials and Methods: H-DPSCs and I-DPSCs were isolated and cultured from 28 teeth consisting healthy impacted third molars (n=14) from patients with 17-27 years of age, and severely decayed molars (n=14) with spontaneous, sharp pain from patients with 24 – 56 years of age, respectively. The levels of IL-6 from H-DPSCs and I-DPSCs were measured by ELISA, and IL-6 and neutralizing IL-6 were added to H-DPSCs and I-DPSCs, respectively. Immunofluorescence and Alizarin Red staining, and western blot were performed to assess the differentiation potentials of DPSCs. The independent unpaired two-tailed Student’s t-test were performed following quantification analysis. Results: H-DPSCs and I-DPSCs showed similar expression of stem cell markers including CD44, CD73, CD90, and CD105, while H-DPSCs showed lower level of IL-6 (p Conclusion: This study showed IL-6 has the capacities to enhance osteogenesis while hindering neurogenesis of DPSCs.