The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST), School & Hospital of Stomatology, Wuhan University, 237# Luoyu Road, Wuhan 430079, China.
Biochem Biophys Res Commun. 2012 Jul 20;424(1):182-8. doi: 10.1016/j.bbrc.2012.06.106. Epub 2012 Jun 27.
Endochondral ossification is a complex process involving chondrogenesis and osteogenesis regulated by many hormones and growth factors. Parathyroid hormone (PTH), one of the key hormones regulating bone metabolism, promotes osteoblast differentiation and osteogenesis by intermittent administration, whereas continuous PTH administration inhibits bone formation. However, the effects of PTH on chondrocyte proliferation and differentiation are still unclear. In this study, intermittent PTH administration presented enhanced effects on condylar chondrocyte differentiation and bone formation, as demonstrated by increased mineral nodule formation and alkaline phosphatase (ALP) activity, up-regulated runt-related transcription factor 2 (RUNX2), ALP, collagen type X (COL10a1), collagen type I (COL1a1), osteocalcin (OCN), bone sialoprotein (BSP), bone morphogenetic protein 2 (BMP2) and osterix (OSX) mRNA and/or protein expression. On the contrary, continuous PTH administration promoted condylar chondrocyte proliferation and suppressed its differentiation, as demonstrated by up-regulated collagen type II (COL2a1) mRNA expression, reduced mineral nodule formation and down-regulated expression of the mRNAs and/or proteins mentioned above. Our data suggest that PTH can regulate condylar chondrocyte proliferation and differentiation, depending on the type of PTH administration. These results provide new insight into the effects of PTH on condylar chondrocytes and new evidence for using local PTH administration to cure mandibular asymmetry.
软骨内骨化是一个复杂的过程，涉及软骨生成和骨生成，受许多激素和生长因子调节。甲状旁腺激素（PTH）是调节骨代谢的关键激素之一，通过间歇给药促进成骨细胞分化和骨生成，而连续给予 PTH 会抑制骨形成。然而，PTH 对软骨细胞增殖和分化的影响尚不清楚。在这项研究中，间歇给予 PTH 对髁突软骨细胞分化和骨形成有增强作用，表现为矿化结节形成和碱性磷酸酶（ALP）活性增加，上调 runt 相关转录因子 2（RUNX2）、ALP、胶原 X 型（COL10a1）、胶原 I 型（COL1a1）、骨钙素（OCN）、骨涎蛋白（BSP）、骨形态发生蛋白 2（BMP2）和osterix（OSX）mRNA 和/或蛋白表达。相反，连续给予 PTH 促进髁突软骨细胞增殖并抑制其分化，表现为 COL2a1 mRNA 表达上调，矿化结节形成减少，上述 mRNAs 和/或蛋白表达下调。我们的数据表明，PTH 可以根据给药类型调节髁突软骨细胞的增殖和分化。这些结果为 PTH 对髁突软骨细胞的作用提供了新的见解，并为使用局部 PTH 给药治疗下颌骨不对称提供了新的证据。
