首页 | 本学科首页   官方微博 | 高级检索  
     


Transforming growth factor-beta inhibition of mineralization by neonatal rat osteoblasts in monolayer and collagen gel culture
Authors:Deanna J. Talley-Ronsholdt  Evelyn Lajiness  Kishan Nagodawithana
Affiliation:(1) Department of Basic Health Sciences, Marquette University School of Dentistry, 604 N. 16th Street, 53233 Milwaukee, Wisconsin
Abstract:Summary The latent form of transforming growth factor-beta (TGF-β) is a component of the extracellular matrix of bone. The active form, when locally injected in vivo, stimulates both inflammation and ectopic bone formation. The present study was undertaken to determine if TGF-β also stimulated mineralization by isolated rat calvarial osteoblasts cultured in collagen gels. Gels were used because they should mimic in vivo conditions better than classical monolayer culture. Compared to cells in monolayers, osteoblasts cultured in collagen gels exhibited slower growth, but higher alkaline phosphatase activity and mineral deposition. Cultured cells also synthesized the osteoblast-specific marker, osteocalcin. The increase in osteocalcin in cell layers was parallel to the increase in mineral deposition. In the presence of TGF-β, neither cell growth nor alkaline phosphatase activity increased. Instead, a small decrease occurred in both parameters when compared to untreated cultures. Accumulation of collagen, the major component of the extracellular matrix where mineralization occurs, was similar in untreated and TGF-β1-treated cultures. However, 8 pM TGF-β1 dramatically suppressed mineral deposition in both types of cultures. Despite TGF-β1 stimulating a fourfold increase in lactic acid, the consequent increase in culture medium acidity did not account for the inhibitory effects of TGF-β1 on mineralization. These results demonstrate that collagen gel culture is an improved technique over conventional monolayer culture for demonstrating differentiated osteoblast function and sensitivity to TGF-β1. TGF-β1, at a concentration that has little effect on cell growth, alkaline phosphatase activity, or collagen accumulation, is a potent inhibitor of mineralization. The mechanism by which TGF-β1 inhibits mineralization remains to be determined.
Keywords:osteoblasts  bone  collagen gels  mineralization  TGF-beta
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号