In vivo extracellular matrix protein expression by human periodontal ligament after stimulation with orthodontic force

It is well known that the orthodontic force applied to teeth generates a series of events that remodel theperiodontal ligament (PDL). Extracellular matrix proteins (ECM) are described as molecular regulatorsof these events. However, the exact contribution of these proteins in human PDL modeling byorthodontic force application in vivo is not known. The aim of this present study was to evaluate theprotein expression of fibronectin, laminin and vitronectin by human PDL from teeth on whichorthodontic force was applied. Twenty healthy individuals were included in the study. PDL wasobtained from teeth after a 3-week treatment with orthodontic force. PDL-protein samples wereseparated on 7.5% SDS-PAGE Western blot analysis with specific monoclonal antibodies forfibronectin, laminin and vitronectin. Bands were visualized with an enhanced chemiluminescencedetection system and densitometric. Scanning of bands was carried out to compare differences inprotein expression. A significant increment in fibronectin (13.9%), laminin (16.5%) and vitronectin(14.2%) expression was found in PDL from teeth treated with orthodontic force for 3 weeks incomparison with teeth in the control group. Our results support the concept that molecular changestake place by application of orthodontic forces to the PDL. Over expression of these proteins suggeststhat extracellular matrix (ECM) remodeling could be generated in response to mechanical stress.