Conclusion
The results of this study indicate that inflammatory stimuli also diminish the 1,25(OH)2 D3 -induced expression of osteogenesis-related factors in hPDLSCs under osteogenic conditions, while having no effect on the osteogenic differentiation.
Methods
Primary hPDLSCs of six donors were cultured in osteogenic induction medium containing either 1,25(OH)2 D3 (0-10 nM) or 25(OH)D3 (0-100 nM) in the presence and absence of Porphyromonas gingivalis lipopolysaccharide (LPS) or Pam3CSK4 for 7, 14 and 21 days. Osteogenic differentiation of hPDLSCs was evaluated by analysis of mineralization as assessed by Alizarin Red S staining and gene expression levels of osteogenesis-related factors osteocalcin, osteopontin and runt-related transcription factor 2 (RUNX2) were analysed with qPCR.
Results
Treatment with 1,25(OH)2 D3 significantly enhanced the osteogenic differentiation of hPDLSCs and their expression of osteocalcin and osteopontin. The 1,25(OH)2 D3 -triggered expression of osteogenesis-related factors was significantly lower in the presence of Pam3CSK4, but not P. gingivalis LPS. None of the inflammatory stimuli had significant effects on the 1,25(OH)2 D3 -induced osteogenic differentiation. 25(OH)D3 neither affected gene expression levels nor osteogenic differentiation of hPDLSCs cultured in osteogenic induction medium.