Abstract: PURPOSE: To investigate the effect of salvia miltiorhiza on the expression of TGF-β₁ within periodontal tissues during orthodontic tooth movement in rat. METHODS: One hundred and ninety-two male Sprague-Dawley rats were randomly divided into 4 groups (group A, B, C and D). Group A and B were used as orthodontic tooth movement model based on afterburner time. Group A, C and B, D were injected salvia miltiorhiza and NS under the buccal mucosa of left maxillary first molar every other day. Animals in each group were sacrificed at 6 time points（day 1,3,5,7,10 and 14) after appliance placement for collection of specimens. The distance of the tooth movement was measured by stereomicroscope, periodontal tissue was investigated by H-E staining and the protein expression of TGF-β₁ was examined by immunohistochemical techniques. SPSS17.0 software package was used for statistical analysis. RESULTS: Except for the first day, the protein expression of TGF-β₁ in group A was highest and there was significant up-regulation on day 3, with a peak on day 5. Compared with group B, the average optical density of TGF-β₁ in group A was 0.5181±0.0037 on day 3, 0.5857±0.00235 on day 5 and 0.4363±0.0021 on day 7, both with significant differences (P<0.01). Compared with group C and group D, significant differences were formed at each time point in group A(P<0.05). CONCLUSIONS: Salvia injection may improve periodontal tissue microcirculation,thus promote the expression of TGF-β₁ protein,which may be one of the mechanisms to accelerate orthodontic tooth movement.

Key words: Salvia miltiorhiza, TGF-β1, Orthodontics, Periodontal tissue