Effects of Force and Inflammatory Factors on the Expressions of Osteogenesis Regulators in Human Periodontal Ligament Cells.

ABSTRACT

Objective To observe the effects of force signals and inflammatory cytokines on the expressions of functional proteins during the differentiation of periodontal ligament cells(PDLCs) into osteoclasts. Methods The caries-free premolars that needed to be removed for orthodontic treatment were collected,human periodontal ligament cells were cultured in vitro.Human PDLCs were exposed to inflammatory cytokines including interleukin(IL)-1ß,-6,-23,and tumor necrosis factor alpha(TNF-α). Cyclicmechanical tension with a maximum 5% elongation for different durations(0,2,4,8,12,and 24 hours) were applied. Then the expressions of signaling molecules related to osteoclastogenesis(OPG) and receptor activated nuclear factor κB ligand(RANKL) were determined at protein levels by Western blotting. Results Inflammatory cytokines improved the expressions of osteoclastgenesis regulators in hPDLCs,while cyclic-tension force reduced their expressions. However,the combined effect of inflammatory cytokines and cyclic-tension force resulted in high expressions of osteoclastgenesis regulators. Conclusion Inflammatory cytokines can promote the expressions of the osteoclastgenic factors,which can not be offset by cyclic-tension force.