J Korean Acad Periodontol.  2008 Aug;38(Suppl):395-404. 10.5051/jkape.2008.38.Suppl.395.

The effect of five osteotropic factors on osteoprotegerin mRNA expression in gingival fibroblasts

• Ko YK

• KMID: 1486874
• DOI: http://doi.org/10.5051/jkape.2008.38.Suppl.395

Abstract

PURPOSE
Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor necrosis factor (TNF) receptor family that inhibits bone resorption by suppressing osteoclastogenesis. Gingival fibroblasts (GF) play a role in periodontal disease progression, and the purpose of this experiment was to evaluate influence of osteotropic factors on the expression of osteoprotegerin mRNA in these cells.
MATERIALS AND METHODS
In this experiment, the influence of osteoclastogenic factors, interleukin-1 beta (IL-1beta), TNF-alpha, prostanglandin E2 (PGE2). parathyroid hormone (PTH) and 1alpha, 25-dihydroxyvitamin D3 on the expression of osteoprotegerin mRNA in GF was studied by Northern blot hybridization.
RESULTS
As expected, PGE2 tended to inhibit OPG levels and this was most prominent at 24 hours of culture with 10(-7)M of PGE2. TNF-alpha at 10ng/ml and also at 25ng/ml decreased OPG levels to almost 30% of the control at 24 hours. This contrasts with reports of increased OPG levels from osteoblast/stromal cells and gingival fibroblasts stimulated by TNF-alpha. Decrease of OPG levels with PGE2 and TNF-alphasuggests a pathway whereby these mediators exert their resorptive effects. However, OPG levels were increased almost 3-fold at 24 hours with IL-1beta(1 to 15ng/ml) and increased 1.4 fold with 24-hour treatment of 10(-7)M PTH.
CONCLUSION
Increase of OPG levels suggests that these 'osteoclastogenic' factors act in more complex ways and may act to inhibit bone resorption in inflammatory periodontitis. This result supports the role of OPG as a negative feedback mechanism in osteoclastic activity.

Keyword

gingival fibroblast; IL-1; osteoclastogenesis; osteoprotegerin

MeSH Terms

Blotting, Northern
Bone Resorption
Dinoprostone
Fibroblasts
Glycoproteins
Humans
Interleukin-1
Interleukin-1beta
Osteoclasts
Osteoprotegerin
Parathyroid Hormone
Periodontal Diseases
Periodontitis
RNA, Messenger
Tumor Necrosis Factor-alpha
Dinoprostone
Glycoproteins
Interleukin-1
Interleukin-1beta
Osteoprotegerin
Parathyroid Hormone
RNA, Messenger
Tumor Necrosis Factor-alpha