Stimulation of the dentine-pulp complex of rat incisor teeth by transforming growth factor-beta isoforms 1-3 in vitro

Expression of transforming growth factor-beta (TGF-beta) isoforms by odonto blasts leads to their sequestration within dentine matrix. TGF-beta(1) and -beta(3) stimulate matrix secretion and also initiate odontoblast cytodiffe rentiation in vitro and in vivo. Using a recently established organ-culture model, the aim here was to examine the effects of TGF-beta isoforms on the response of the dentine-pulp complex during culture. Agarose beads were so aked in isoforms 1 3, and placed on the odontoblast area of slices of 28-da y-old rat incisor tooth. The slices were maintained in Trowel-type cultures for 7 days. Both TGF-beta(1) and -beta(3) stimulated a local increase in p redentine secretion at the site of the bead application when compared to co ntrol cultures. Mitogenic effects on the cells of the subodontoblast layer were also seen and occasionally small foci of newly differentiated odontobl ast-like cells could be observed a little distant from the application site of TGF-beta(3). TGF-beta(2) had 3 minimal effect on the cultured tissues. These results demonstrate that TGF-beta(1) and -beta(3) can stimulate secre tion of extracellular matrix by odontoblasts, are mitogenic to pulp cells, and that TGF-beta(3) may have inductive effects: on pulpal cells. Such acti vities might be important during reparative processes in the dentine-pulp c omplex after tissue injury. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.