Stimulatory effects of simvastatin on bone regeneration of the expanded suture in rats

Simvastatin belongs to the family of statins and is found to have some osteopromotive properties in recent years. The aim of the present study was to investigate the potential effects of simvastatin on bone formation of the expanded mid-palatal suture of rats. Forty-five Wistar rats were randomly divided into three groups: control (C), expansion (EP), and expansion plus simvastatin (ES) groups. Rats in the ES group were administrated with simvastatin (20 mg/kg/d body weight). According to the schedule of sacrifice (days 3, 7 and 14), the suture width and bone volume changes of the region of interest (ROI) were detected by micro-computed tomography during RME. Besides, morphological changes and bone morphogenetic protein 2 (BMP-2) expression in the mid-palatal suture were observed by hematoxylin and eosin (HE) and immunohistochemical staining. Kruskal-Wallis one-way analysis of variance (ANOVA) and LSD method were applied to analyze the data at P<0.05 level. By the RME appliance, the suture was successfully widened. On days 7, 14, the bone volume of ROI in the ES group was more than that in the EP group (P<0.05). Besides, histological examinations also demonstrated that more bone regeneration and capillaries in the suture in the ES group were observed than that in the EP group. The BMP-2 expression in the ES group was more (P<0.05) than that in the EP and C groups on days 3, 7, 14. Consequently, those findings showed that simvastatin can induce a favorable effect on bone regeneration in the mid-palatal suture of rats during RME.