The effect of progressive tensional force on mRNA expression of osteoprotegerin and receptor activator of nuclear factor kappa B ligand in the human periodontal ligament cell / 대한치과교정학회지

ABSTRACT

Tooth movement is a result of mutual physiologic responses between the periodontal ligament and alveolar bone stimulated by mechanical strain. The PDL cell and osteoblast are known to have an influence on bone formation by controlling collagen synthesis and alkaline phosphatase activation. Moreover, recent studies have shown that the PDL cell and osteoblast release osteoprotegerin (OPG) and the receptor activator of nuclear factor kappa B ligand (RANKL) to control the level of osteoclast differentiation and activation which in turn influences bone resorption. In this study, progressively increased, continuous tensional force was applied to PDL cells. The objective was to find out which kind of biochemical reactions occur after tensional force application and to illuminate the alveolar bone resorption and apposition mechanism. Continuous and progressively increased tensile force was applied to PDL cells cultured on a petriperm dish with a flexible membrane. The amount of PGE2 and ALP synthesis were measured after 1, 3, 6 and 12 hours of force application. Secondly, RT-PCR analysis was carried out for OPG and RANKL which control osteoclast differentiation and MMP-1, -8, -9, -13 and TIMP-1 which regulate the resolution of collagen and resorption of the osteoid layer. According to the results, we concluded that progressively increased, continuous force application to human PDL cells reduces PGE2 synthesis, and increases OPG mRNA expression.