Abstract:

Abstract:Objective
To investigate the effect of local application of simvastatin on the expression of bone morphogenetic protein-2(BMP-2)  in the tooth socket following tooth extraction and discuss its mechanism. Methods Fifty-eight male Wistar rats were divided into experimental group and control group (n=28). PLGA was immediately implanted with or without simvastatin into extraction sockets of the mandibular incisors. Oligonucleotide probe specific to BMP-2 mRNA was designed,and hybridization technique was conducted 5 d,1 week,2 weeks and 4 weeks after implantation.Results There were no positive cells in both experimental group and control group 5 d after implantation. There were deep-dying positive stromal cells between the implanted material and the wall of tooth socket in experimental group,and a few light-dying positive cells could be seen in control group 1 week after implantation. There were many positive cells with clear particles  in the stromal cells between the implanted  material and the wall of tooth socket,and there were also BMP-2 mRNA  positively expressed cells on the surface of newly-formed osteoid in two  groups,and the number of the positive cells in experimental group was higher than that in control group 2 weeks after implantation. There were BMP-2 mRNA  positive cells  in both the experimental group and the control group 4 weeks after implantation. The number of BMP-2  positive cells in experimental group was significantly higher than that in control group 1,2,4 weeks after implantation (P<0.05). Conclusion Topical application of simvastain could promote alveolar bone repair by up-regulating BMP-2 mRNA expression.

Key words: simvastatin;　 alveolar bone;　BMP-2 mRNA