甲状旁腺激素在体外对破骨细胞分化及骨重吸收能力的影响

目的 探讨甲状旁腺激素(PTH)在体外直接对破骨细胞(OCs)分化及骨吸收能力的影响，以及其与成骨细胞(OBs)中核因子kB受体激活剂受体配体(ligand of receptor activator of nuclear factor kappa B，RANKL)基因和OPG(osteoprotegerin)基因表达的关系。方法体外直接用PTH诱导C3h小鼠全骨髓分化出OCs，用牙片小坑法(pits assayr)观察OCs对骨的重吸收能力。并采用多重RT-PCR方法检测在不同PTH作用浓度和不同作用时间的条件下,OBs中RANKL基因和OPG基因的表达情况。结果(1)PTH在体外可诱导C3h小鼠全骨髓分化出OCs，且在一定浓度范围内，随着PTH增加，OCs的形成数目和骨组织的破坏程度随之增加；(2)在一定PTH浓度和时间范围内，OBs中的RANKL-mRNA及OPG-mRNA表达呈剂量依赖性和时间依赖性。结论 PTH在体外可通过诱导RANKL基因和OPG基因表达而直接影响OCs的分化和骨重吸收功能。

Effect of parathyroid hormone on differentiation and resorption of osteoclasts in vitro

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.