Messenger RNA level and protein localization of transforming growth factor-beta1 in experimental tooth movement in rats.

Transforming growth factor-beta1 (TGF-beta1) is known to be associated with local bone remodeling. We hypothesize that TGF-beta1 is induced in bone and regulates adaptive alveolar bone modeling during tooth movement. To test this hypothesis, we examined the steady-state mRNA level of TGF-beta1 and the protein localization of TGF-beta1 and its type II receptor (TbetaR-II) during experimental tooth movement. Maxillary right molars, M1, M2 and M3, of rats were moved palatally for 1, 3 and 7 d by a finger coil spring anchored to the upper incisors. The contralateral side was used as a control. After 3 d of tooth movement, intense immunostaining for TGF-beta1 and TbetaR-II was observed in cuboidally shaped osteoblasts in the tension zone, and in bone-resorbing osteoclasts in the compression zone. On the control side, few active osteoblasts and osteoclasts were observed. Reverse transcriptase-competitive polymerase chain reaction revealed significant increases in TGF-beta1 mRNA in alveolar bone cells on the tooth movement side on day 3 and day 7. Taken together, our data indicate that TGF-beta1 is induced during tooth movement and we propose that this may regulate adaptive alveolar bone modeling.