Effects of a peptide containing arginine-glycine-aspartic acid (echistatin) on root resorption in rats

The aim of this study is to explore cellular mechanisms that decrease induced root resorption in orthodontically treated teeth. The specific objectives were to immunohistochemically examine whether alphavbeta3 integrin receptors are expressed by odontoclasts during experimental tooth movement; to examine the effects of an RGD containing peptide, echistatin on induced root resorption and on the number and the fine structure of clast cells; as well as its effect on the rate of tooth movement.;A total of 33 Sprague-Dawley rats were used. Tooth movement was achieved by placing an elastic band between the maxillary right first and second molars for 24 hours. Sixteen animals were used for the localization of the alphavbeta3 integrin receptor in odontoclasts and osteoclasts. Two polycolonal antibodies were used, one against the alphav subunit and one against the beta3 subunit of the integrin receptor. To examine the effects of echistatin on induced root resorption, 14 rats were equally divided into two groups; experimental animals received echistatin intravenously for 8 hours (0.8 mug/kg/min) and control which received sterile water. Impressions were taken of the maxillary dental arch including the palate and models cast to measure the rate of tooth movement. Echistatin labeled with a fluorescent marker was used to confirm its presence in clast cells. Cytochemically, tartrate-resistant acid phosphatase wag used to quantify mature and committed clast cells.;The alphavbeta3 integrin was expressed by odontoclasts and osteoclasts during tooth movement. Echistatin significantly inhibited root resorption surface area (p < 0.01) and reduced the number of root resorption lacunae (p < 0.01). There was no statistically significant difference in clast cell numbers nor were any clear fine structural alterations in these cells. Echistatin had no effect on the amount of tooth movement. In conclusion, targeting alphavbeta3 integrin receptor expressed by odontoclasts can be effective in reducing the degree of root resorption during tooth movement. Further studies are needed to elucidate the mechanism of this inhibition by the RGD containing peptide echistatin.