Local delivery of EGF-liposome mediated bone modeling in orthodontic tooth movement by increasing RANKL expression.
OBJECTIVE
It has long been demonstrated that epidermal growth factor (EGF) has catabolic effects on bone. Thus, we examined the role of EGF in regulating mechanically induced bone modeling in a rat model of orthodontic tooth movement.


METHODS
The maxillary first molars of rats were moved mesially using an orthodontic appliance attached to the maxillary incisor teeth. Rats were randomly divided into 4 groups: (G1) administration of PBS (phosphate buffer saline) solution (n=24); (G2) administration of empty liposomes (n=24); (G3) administration 20ng of EGF solution (n=24); and (G4) 20ng of EGF-liposomes solution (n=24). Each solution was injected in the mucosa of the left first molar adjacent to the appliance. At days 5, 10, 14 and 21 after drug administration, 6 animals of each group were sacrificed. Histomorphometric analysis was used to quantify osteoclasts (Tartrate-resistant acid phosphatase (TRAP)+cells) and tooth movement. Using immunohistochemistry assay we evaluated the RANKL (receptor activator of nuclear factor kappaB ligand) and epidermal growth factor receptor (EGFR) expression.


RESULTS
The EGF-liposome administration showed an increased tooth movement and osteoclast numbers compared to controls (p<0.05). This was correlated with intense RANKL expression. Both osteoblasts and osteoclasts expressed EGFR.


CONCLUSIONS
Local delivery of EGF-liposome stimulates osteoclastogenesis and tooth movement.
Laboratory of Molecular Biology, University of Uberaba, Uberaba, MG, Brazil. propg.pr@uniube.br
José B
JB
Alves
Cynthia L
CL
Ferreira
Aline F
AF
Martins
Gerluza A B
GA
Silva
Guilherme D
GD
Alves
Tony P
TP
Paulino
Pietro
P
Ciancaglini
Geraldo
G
Thedei
Marcelo H
MH
Napimoga
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D016723:Bone Remodeling / Q000187:drug effects*; D004337:Drug Carriers; D004815:Epidermal Growth Factor / Q000008:administration & dosage* / Q000494:pharmacology*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D008081:Liposomes; D008297:Male; D009970:Orthodontics; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects; D053245:RANK Ligand / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071681:Tartrate-Resistant Acid Phosphatase; D014087:Tooth Movement Techniques
D004337:Drug Carriers; D007527:Isoenzymes; D008081:Liposomes; D053245:RANK Ligand; D004815:Epidermal Growth Factor; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase