Upregulation of immunoreactivity of endothelin-1 and alpha-SMA in PDL microvasculature following acute tooth loading: an immunohistochemical study in the marmoset.
OBJECTIVE
To test the hypothesis that a continuous mechanical tooth load would elevate immunoreactivity of endothelin-1 (ET-1) and alpha-smooth muscle actin (alpha-SMA) in the periodontal ligament (PDL) microvasculature.


METHODS
A randomized control study employing 1.5 h of loading to first molars.


METHODS
Orthodontic Research Laboratory, Dental School, Adelaide University. Four young adult, male marmoset monkeys were consecutively anaesthetized and treated.


METHODS
An external telescoping frame applied a jaw closing load (120-200 g) transmitted occlusally, via a rubber pad, to randomly assigned mandibular left or right first molars. Contralateral molars were used as controls.


METHODS
Undemineralized, midsagittal, mandibular molar slices, approximately 150 microm thick were immunolabelled with ET-1 and alpha-SMA antibodies and examined in a confocal laser scanning microscope (CLSM) for vascular endothelium and smooth muscle immunolabelling.


RESULTS
Three categories of post-capillary-sized venule endothelial cell immunolabelling occurred: endothelium labelled solely with ET-1; endothelium labelled solely with alpha-SMA; endothelium labelled with both ET-1 and alpha-SMA. In endothelial cells, the alpha-SMA showed a moderate cytoplasmic distribution with dense peripheral concentration. Loading increased arteriole alpha-SMA actin labelling.


CONCLUSIONS
Scattered expression of ET-1 is the default state in primate PDL endothelial cells. Increased antigenicity of endothelial cells to both ET-1 and alpha-SMA, and of arteriolar smooth muscle to alpha-SMA, is a response to shear and compression loads.
Sims
M R
MR
Microcirculation and Lymphology Laboratory, Flinders University, Visiting Research Fellow Orthodontic Unit, Dental School, Adelaide University, South Australia, Australia.
Ashworth
J F
JF
Sampson
W J
WJ
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002144:Callithrix; D003799:Dental Stress Analysis; D019332:Endothelin-1 / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D008297:Male; D008833:Microcirculation / Q000378:metabolism; D008963:Molar; D009130:Muscle, Smooth / Q000378:metabolism; D010513:Periodontal Ligament / Q000098:blood supply*; D015854:Up-Regulation
D000199:Actins; D019332:Endothelin-1