Proinflammatory cytokine expression in cyclooxygenase-2-deficient primary osteoblasts.
Many of the proinflammatory effects of interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha) are mediated through cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2). The purpose of this study was to examine the expression of IL-1beta and TNF-alpha in COX-2-deficient osteoblasts during inflammation. Primary osteoblasts prepared from wild-type (WT) and COX-2 knockout (K/O) mice were exposed to lipopolysaccharide (LPS) and endodontic obturation materials. An enzyme-linked immunosorbent assay was used to measure cytokine levels. LPS treatment led to a significant upregulation in IL-1beta and TNF-alpha levels in both WT and K/O cells. TNF-alpha upregulation in response to LPS was much more pronounced in K/O cells compared with WT cells (p < 0.05). All materials tested except for gutta percha caused an increase in IL-1beta expression. In conclusion, there appears to be a positive feedback regulation between TNF-alpha and COX-2-dependent PGE2 during LPS-induced inflammatory reactions.
He
Jianing
J
Department of Endodontics, Baylor College of Dentistry, The Texas A&M University Health Science Center, Dallas, Texas 75246, USA. jhe@bcd.tamhsc.edu
Tomlinson
Rosamond
R
Coon
David
D
Gulati
Ajay
A
Cowan
Cameron
C
D000818:Animals; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000172:deficiency*; D015232:Dinoprostone / Q000096:biosynthesis*; D005260:Female; D053583:Interleukin-1beta / Q000096:biosynthesis*; D008070:Lipopolysaccharides; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D012387:Root Canal Filling Materials / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D012387:Root Canal Filling Materials; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; D015232:Dinoprostone