RESUMO
Objective To study the direct effect of parathyroid hormone(PTH) on osteoclasts (OCs) differentiation and bone resorption in vitro and to explore the relationship between PTH and expression of RANKL (ligand of receptor activator of nuclear factor kappa B)gene and OPG (osteoprotegerin) gene in osteoblasts (OBs) in order to provide some theoretic evidence for understanding the pathogenesis of high-transferred renal osteodyslrophy (ROD). Methods PTH was directly used to induce OCs differentiation from whole bone marrow of C3h mouse by using OCs formation assay and then inspected the bone resorption of these OCs in vitro by using pits assay. Multiple RT-PCR assay was used to examine the expression of RANKL-mRNA and OPG-mRNA in different PTH concentrations and different treating times by PTH. Results (1) PTH in vitro could induce OCs formation form whole bone marrow of wild-type C3h mice.In a certain concentration scope, as the concentration of PTH increased, the number of differentiated OCs and the degree of bone destruction of OCs increased. (2) Expression of RANKL-mRNA and OPG-mRNA was in dose-dependent and time-dependent manner within a certain range of concentration and time. Conclusion PTH in vitro mediates OCs differentiation and bone resorption probably through the up-regulated expression of RANKL-mRNA and OPG-mRNA.