Combined effect of TNF-α and cyclic stretching on gene and protein expression associated with mineral metabolism in cementoblasts

Abstract Objective This work aims to investigate how the combination of TNF-α and cyclic stretching affects the expression of gene and protein associated with mineral metabolism in cementoblasts in vitro. Design Cementoblasts were cyclically stretched using the Flexcell tension system 4000 in the presence of 10 ng/ml TNF-α. Subsequently, the gene and protein expression CAP, Col I, BSP, OPG, RANKL and RUNX2 were detected using RT- PCR and ELISA/Western immunoblotting methods, respectively. Results Cyclic stretching alone enhanced CAP, Col I, OPG, RANKL and RUNX2 expression in an amplitude manner, while decreased BSP expression. Expression of all these proteins was attenuated in the presence of TNF-α whether the cells were exposed to cyclic stretching or not. The ratio of RANKL/OPG was increased at any stimulation. Conclusion This results suggest that TNF-α affected the regulation of gene and protein expression induced by mechanical stimulation in cementoblasts. This may suppress anabolism and promote catabolism of cementum. It suggests that inflammatory cytokine may impair the cementum remodeling under mechanical stimulation.