title: Effects of intermittent versus continuous parathyroid hormone administration on condylar chondrocyte proliferation and differentiation.
abstract: 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.
authors: 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.
authors: Qi
authors: Q
authors: Liu
authors: Qilong
authors: Q
authors: Wan
authors: Rongtao
authors: R
authors: Yang
authors: Haihua
authors: H
authors: Zhou
authors: Zubing
authors: Z
authors: Li
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects*; D024043:Collagen Type II / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D005260:Female; D008335:Mandibular Condyle / Q000166:cytology* / Q000254:growth & development* / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D053495:Osteopontin / Q000378:metabolism; D010281:Parathyroid Hormone / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; C511513:COL2A1 protein, rat; D024043:Collagen Type II; D050659:Core Binding Factor Alpha 1 Subunit; D010281:Parathyroid Hormone; C506897:Spp1 protein, rat; D053495:Osteopontin