Immunohistochemical Study of Transforming Growth Factor-β during Experimental Tooth Movement in Rats

Abstract

     Using histochemical methods, we studied the changes in transforming growth factor-β (TGF-β) caused by tooth movement. TGF-β is a peptide growth factor which is abundant in bone and acts on osteoblasts and osteoclasts.
      Male Wistar rats weighing about 200 g were killed at 6, 12, 18 and 24 hours, and 3, 7 and 14 days after initiation of tooth movement, and paraffin sections 6μm in thickness were cut from the left maxillary molars. Sections from the right molars were used as controls. The sections were stained by the immunohistochemical (LSAB) method and H.E. staining. Examination was concentrated on the periodontal tissue mesial to the mesial root of the first molar.
      TGF-β-immunoreactivity was found in the periodontal ligament. There was strong TGF-β-immunoreactivity in multinuclear osteoclast cells in the ruffled border at 12, 18, and 24 hours after tooth movement, there was also strong TGF-β-immunoreactivity at the bone edge at 12 hours after tooth movement, and strong TGF-β-immunoreactivity in blood vessels at 24 hours. Strong TGF-β-immunoreactivity was also observed in new bone after initiation of tooth movement.
      These results suggest that TGF-β is a factor in controlling bone resorption and formation resulting from tooth movement.