In VivoStimulation of Bone Formation by Transforming Growth Factor-β

Abstract

The effect of transforming growth factor-.beta. (TGF.beta.) on bone in vivo was examined. Twelve daily injections of 1 .mu.g TGF.beta. directly onto the periostea of parietal bones of neonatal rats stimulated the formation of periosteal woven bone. The thickness of the treated parietal bones increased at least 2-fold in a dose-dependent manner. This TGF.beta. effect was localized at the sites of injection, and no change was observed in contralateral parietal bones and tibiae. The body weight in these growing rats was not affected by TGF.beta.1. TGF.beta.2 had effects similar to those of TGF.beta.1 on the parietal bones in vivo. These results reveal for the first time that TGF.beta. stimulates bone formation in vivo and indicate its anabolic role in local bone metabolism.