Parathyroid hormone/parathyroid hormone-related peptide modulates growth of avian sternal cartilage via chondrocytic proliferation.
Parathyroid hormone (PTH; 10(-7) to 10(-15) M) decreased terminal chondrogenesis in the avian sterna. During the first half of an 8-day culture, 100 nM PTH (1-34) significantly increased sternal length and downregulated the deposition of type X collagen and its mRNA expression. However, it remains unclear how PTH increased cartilaginous growth. In this study, we examined growth by both cell proliferation and analysis of cyclin d1 and collagen mRNA. Types II, IX, and X collagens and cyclin d1 mRNA were quantified through real-time RT-PCR, while Ki-67 was used as an immunohistochemical proliferation marker. Extracellular matrix content was measured through mRNA quantification of types II, IX, and X collagen and observing deposition of the same collagens. PTH significantly increased the proliferation marker Ki-67 in the sternal cephalic region. There was less type II and X collagen in PTH-treated sterna with concomitant decreases in mRNA production, suggesting that proliferation was the major contributor to cartilage growth in the presence of PTH/PTH-related peptide receptor activation. In conclusion, these experiments demonstrated that PTH increased cartilage growth by upregulating cell proliferation or other extracellular matrix components.
Harrington
Erik Kern
EK
Biomedical Sciences, Texas A&M University System, Baylor College of Dentistry, Dallas, Texas 75246, USA.
Roddy
Gavin W
GW
West
Randy
R
Svoboda
Kathy K H
KK
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002642:Chick Embryo; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism*; D020219:Chondrogenesis / Q000187:drug effects; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D051457:Hyaline Cartilage / Q000187:drug effects / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D009924:Organ Culture Techniques; D010281:Parathyroid Hormone / Q000378:metabolism; D044162:Parathyroid Hormone-Related Protein / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013249:Sternum / Q000187:drug effects / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D019379:Teriparatide / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors
D019394:Ki-67 Antigen; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D012333:RNA, Messenger; D019379:Teriparatide; D019938:Cyclin D1; D003094:Collagen; C035748:parathyroid hormone (1-34)amide