Effects of osthole on bone regeneration in the mid-palatal suture of rats during rapid maxillary expansion

This study aimed at evaluating the effects of osthole on the mid-palatal suture remodeling during rapid maxillary expansion (RME). Rats were randomly separated into three groups: control, expansion only (EO), and expansion plus osthole (OST) groups. An orthodontic appliance was set on rat molars of EO and OST groups and rats in OST group were administrated with osthole (20 mg/kg/day). The suture width and bone volume changes were observed by micro-computed tomography (microCT) and hematoxylin and eosin (HE) staining. Alkaline phosphatase (ALP) and Nel-like molecule-1 (NELL-1) expression were also examined for the assessment of bone formation in the suture. The mid-palatal suture was expanded by the force, but there were no statistically significant differences (P > 0.05) in the width between EO and OST groups. Bone volume of the mid-palatal suture decreased during RME, but increased in the OST group on day 10 compared with EO group. Moreover, ALP and NELL-1 expression of OST group were more than that of the other two groups (P < 0.05). Our data suggest that osthole may be a potential agent to accelerate bone formation of the mid-palatal suture during RME.