Abstract:

Objective To study the influence of simvastatin on the expression of vascular endothelial growth factor(V
EGF) in periodontal tissue of rats during the retentive stage after tooth movement and to explore the effect and mechanism of simvastatin on the remodeling of periodontal tissue during the retention stage. Methods 78 male Wistar rats were randomly divided into 3 groups.The rats in negative control group didn’t receive any treatment.The maxillary first molars of rats in control group were moved to the mesial by closed coil spring running between upper first molar and anterier tooth for 21d and then retentive appliances were placed on the molars in the left side. The retentive appliances were maintained respectively for 1,3,7,14,21 and 28 d. During the retentive stage,the rats  received intraperitoneal injection of normal saline once a day.The rats in  experiment group were treated the same as control group,but they were administered with simvastatin solution instead of normal saline. At the end of the retention,the rats were executed and the changes of VEGF expressions were examined in the periodontal tissue of the moved teeth by using the immunohistochemical staining method and quantitative analysis method. Results In control group,the expression of VEGF was changed indistinctly at the early stage of retention and decreased at the later stage. In experiment group,the expression of VEGF was increased gradually but changed indistinctly at the later stage. Compared with the corresponding time of control group,the VEGF expression was significantly increased in experiment group,there was significant difference between two groups(P<0.05).The VEGF expression on the 28th day in control group had no significant difference compared with negative control group,but the VEGF expressions at the other days except the  28th day were higher than those in negative control group(P<0.05).Conclusion Systemic administration of simvastatin can increase the expression of VEGF in periodontal tissue of rats during the retentive stage after  experimental tooth movement.

Key words: simvastatin；tooth movement；periodontal tissue；vascular endothelial growth factor；bone remodeling