Isoproterenol accelerates the movement of the orthodontic tooth in rats / 医学研究生学报

ABSTRACT

ObjectiveIsoproterenol (ISO) stimulates the β2-adrenoceptor to enhance osteoclast formation, thus accelerating bone resorption. This study was to explore the effect of β-adrenoceptor agonist ISO on orthodontic tooth movement in rats.MethodsForty healthy 8-week-old SD male rats with the upper right first molar moved proximally by 50 g force application were randomly divided into an ISO and a control group and injected intraperitoneally with ISO at 5 mg/kg/d and the same amount of saline, respectively. Five rats were sacrificed in each group after 0, 7, 14 and 21 days of orthodontic force application and the upper right maxillary harvested for measuring the distance of movement of the upper right first molar, observing the changes in the periodontal tissue by HE staining, and counting the osteoclasts by tartrate-resistant acid phosphatase staining (TRAP).ResultsAt 7, 14 and 21 days of orthodontic force application, the tooth movement distance was significantly larger in the ISO group (\[0.52±0.04\], \[0.84±0.05\] and \[1.11±0.15\] mm) than in the control (\[0.40±0.07\], \[0.62±0.06\] and \[0.85±0.07\] mm) (P<0.05). On HE staining, the alveolar bone resorption at the pressure side was the most significant at 14 days, and obvious new bone formation was observed in the alveolar bone at 21 days. At 7, 14 and 21 days, TRAP staining showed remarkably larger numbers of osteoclasts in the ISO group (13.8±3.3, 24±6.3 and 18.8±2.6) than in the control (9.6±1.9, 14.6±3.7, 10.4±3.1) (P<0.05).ConclusionIsoproterenol can increase the number of osteoclasts and accelerate the movement of the orthodontic tooth in rats.