Involvement of PGE synthesis in the effect of intermittent pressure and interleukin-1 beta on bone resorption.
Human periodontal ligament (PDL) fibroblasts, cultured from extracted healthy premolars, and a cloned osteogenic cell line (MC3T3-E1) were used in this study to determine the effect of intermittent pressure on bone resorption. Cells (1 x 10(5] were incubated with BGJb medium in the presence or absence of the following factors: intermittent negative (-30 g/cm2) or positive (30 g/cm2) hydrostatic pressure and interleukin-1 beta (IL-1 beta, 1 ng/mL), for 24 h. Conditioned media (CM) generated from cultures of either cell types were used for prostaglandin E (PGE) assay, bone resorption assay, and assessment of osteoclast (OC)-like cell formation. Unstimulated PDL fibroblasts or MC3T3-E1 cells produced measurable amounts of PGE and bone-resorbing activity as measured by 45Ca released from mouse calvaria and OC-like cells. IL-1 beta-treated cells showed significantly elevated levels of PGE, bone resorption, and OC-like cell formation, as compared with unstimulated cells. Intermittent positive pressure (IPP) alone stimulated PGE production, but the resultant CM did not stimulate bone resorption or OC-like cell formation when IPP was applied to either cell type. The application of IPP, together with IL-1 beta in CM, caused a slight increase in the number of alpha-like cells, as compared with that of IL-1 beta-treated CM in both cell types. On the other hand, direct application of IPP on mouse bone-marrow cultures significantly increased the number of OC-like cells. This effect was additive in combination with either CM from unstimulated cells or exogenous addition of PGE2.(ABSTRACT TRUNCATED AT 250 WORDS)
Saito
S
S
Department of Orthodontics, Showa University, Tokyo, Japan.
Ngan
P
P
Rosol
T
T
Saito
M
M
Shimizu
H
H
Shinjo
N
N
Shanfeld
J
J
Davidovitch
Z
Z
D000818:Animals; D001854:Bone Marrow Cells; D001862:Bone Resorption / Q000378:metabolism / Q000503:physiopathology*; D002118:Calcium / Q000493:pharmacokinetics; D002452:Cell Count; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D002999:Clone Cells; D003470:Culture Media; D005347:Fibroblasts / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D051379:Mice; D010006:Osteoblasts / Q000378:metabolism* / Q000502:physiology; D010010:Osteoclasts / Q000201:enzymology / Q000378:metabolism / Q000502:physiology; D010513:Periodontal Ligament / Q000166:cytology*; D011312:Pressure; D011458:Prostaglandins E / Q000096:biosynthesis*; D013997:Time Factors
D003470:Culture Media; D007375:Interleukin-1; D011458:Prostaglandins E; D002118:Calcium