The effects of dried root aqueous extract of Salvia miltiorrhiza and its major ingredient in acceleration of orthodontic tooth movement in rat

OBJECTIVES Salvia miltiorrhiza (SM) is a popular and classic herb in traditional Chineses medicines. The objective is to confirm the effects of aqueous extract of S. miltiorrhiza (ESM) and its main ingredient on the promotion of orthodontic tooth movement and healing of periodontal ligament in rat. MATERIALS AND METHODS Male Sprague-Dawley rats (n= 150) were divided into five groups: model control group (0.5 ml/kg phosphate-buffered saline (PBS) injection), ESM group (0.75 g/kg/day of crude drugs) and Danshensu subgroups (250, 500, 750 mg/kg/day of body weight). All rats were administered intramuscularly into the buccal vestibular mucosa of first molar of left maxillary. The indicators such as the moving distance of orthodontic tooth, nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG) expression and osteoclasts were tested. RESULTS The expressions of RANKL and OPG in the treatment groups were obviously enhanced compared with control group (P<0.05). The increase rate of OPG expression was slower than that of RANKL. But, RANKL decreased conspicuously after no orthodontic pressure was applied, especially in the treatment groups (Danshengsu high dose group at day 30: 2.17 versus 3.47 of control, P<0.01). ESM groups promoted osteoclasts proliferation in the first 20 days. CONCLUSION There is a relationship between RANKL/OPG ratio and the number of osteoclasts. ESM might accelerate periodontal alteration of rat orthodontic tooth via producing more osteoclasts.