Ease effects of local inj ection of ursolic acid on orthodontic tooth movement and root resorption of rats and their mechanisms / 吉林大学学报(医学版)

ABSTRACT

Objective:To investgate the ease effects of local injection of ursolic acid both on orthodontic tooth movement distance and tooth root resorption in the rats, and to clarify its mechanism.Methods:Ninety-six male Wistar rats were used to establish models of orthodontic tooth movement.After the successful establishment of models,all the model rats were randomly divided into 0 (control group),0.5,1.0 and 2.0 mmol·L-1 ursolic acid groups (n=24).The rats were locally injected with different doses of ursolic acid into the palatal submucosal area adjacent to the right upper first molar ,once per 3 d,each time 50μL.The rats were respectively sacrificed on the days 1,3,5,7,10,14,21 and 28,then the distances of tooth movement were measured.HE staining was used to observe the morphologic changes of the root tissue of rats.Results:The tooth movement distances of rats in control,0.5,1.0,and 2.0 mmol· L-1 ursolic acid groups were increased with the prolongation of time (P0.05),but at the other time points,the tooth movement distances of rats had statistical significance (P<0.01).The tooth movement distances of rats had statistical significance between 0.5,1.0 and 2.0 mmol·L-1 ursolic acid groups 5,7,10,14,21 and 28 d after forcing (P<0.05 or P<0.01).The morphological results showed that the resorption pits were found on the surface of tooth root with the prolongation of loading time;in addition,with the increasing of the doses of ursolic acid, the absorption of root surface was relieved. Conclusion:Local injection of ursolic acid at the doses of 0.5,1.0 and 2.0 mmol·L-1 can reduce the distance of orthodontic tooth movement in the rats, and the distance of tooth movement in the rats is reduced with the increasing of its doses,and ursolic acid has the ease effect on the orthodoutic tooth root resorption.