MEPE expression in osteocytes during orthodontic tooth movement.
MEPE and DMP1 may play a role in mineralisation and demineralisation within the osteocyte microenvironment. Our earlier studies showed that DMP1 is mechanically responsive [Gluhak-Heinrich J, Ye L, Bonewald LF, Feng JQ, MacDougall M, Harris SE, et al. Mechanical loading stimulates dentin matrix protein 1 (DMP1) in osteocytes in vivo. J Bone Min Res 2003;18(5):807-17].


OBJECTIVE
To examine the effect of mechanical loading on the expression of MEPE using mouse tooth movement model, and compare this effect to that on DMP1.


METHODS
In situ hybridisation and immunohistochemistry was performed on 38 treated and 38 control bone sites loaded 6-72 h. ImageJ was used for quantification of mRNA expression in osteocytes.


RESULTS
Alveolar osteocytes showed high basal level of MEPE that decreased during the first day of loading, followed by 2.8-fold stimulation at day 3, and returning to a control level by day 7.


CONCLUSIONS
The osteocyte specific mechanical stimulation of MEPE was delayed and different, compared to that of DMP1. This suggests a distinct role of MEPE and DMP1 in the response of osteocytes to mechanical loading in vivo.
Gluhak-Heinrich
J
J
Department of Orthodontics, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA. gluhak@uthscsa.edu
Pavlin
D
D
Yang
W
W
MacDougall
M
M
Harris
S E
SE
D000539:Alveolar Process / Q000166:cytology; D000818:Animals; D016326:Extracellular Matrix Proteins / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D023421:Models, Animal; D010011:Osteocytes / Q000166:cytology*; D010750:Phosphoproteins / Q000032:analysis*; D010812:Physical Stimulation; D012333:RNA, Messenger / Q000032:analysis; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques
C513308:Dmp1 protein, mouse; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; C518716:Mepe protein, mouse; D010750:Phosphoproteins; D012333:RNA, Messenger