Induction of cyclooxygenase-2 mRNA and protein expression in human gingival fibroblasts stimulated with nicotine

J Periodontal Res. 2003 Oct;38(5):496-501. doi: 10.1034/j.1600-0765.2003.00681.x.


Background: Cigarette smoking is a major risk factor in the development and further progression of periodontal diseases. COX-2 is an inducible enzyme believed to be responsible for prostaglandin synthesis at site of inflammation. Currently, there is limited information on the regulation of COX-2 expression in smoking-associated periodontal disease.

Objectives: The aim of the present study was to investigate the effects of nicotine on the expression of cyclooxygenase-2 (COX-2) mRNA gene and protein in cultured human gingival fibroblasts (HGFs). Furthermore, to elucidate whether induction of COX-2 may be associated with nicotine- induced cytotoxicity, NS-398 (a selective COX-2 inhibitor), was added to test its protective effect.

Methods: The quantitative reverse-transcriptase polymerase chain reaction and Western blot assays were used to investigate the effects of human HGFs exposed to nicotine. In addition, NS-398 was added to test how it modulated the effects of nicotine.

Results: The exposure of quiescent human HGFs to nicotine resulted in the induction of COX-2 mRNA expression. The levels of the COX-2 mRNAs increased about 1.5 and 2.5 fold after exposure to 2.5 and 15 mm nicotine for 2 h (P < 0.05), respectively. Moreover, the peak of COX-2 mRNA levels induced by nicotine was 10 mm at 2 h incubation period. Investigations of the time dependence of COX-2 mRNA expression in nicotine-treated HGFs revealed a rapid accumulation of the transcript, a signal first detectable at 30 min and diminished to control level after 8 h. In addition, 10 mm nicotine also induced COX-2 protein expression in HGFs. The kinetics of this response showed that COX-2 was detectable at 4 h and diminished nearly to control level after 24 h. NS-398 at non-cytotoxic dose is not able to prevent nicotine-induced cytotoxicity.

Conclusions: Taken together, the activation of COX-2 expression by nicotine suggests a potential role for nicotine in the pathogenesis of smoking-associated periodontal disease. In addition, nicotine-induced cytotoxicity is not directly via the induction of COX-2 expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Cyclooxygenase 2
  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors / pharmacology
  • Enzyme Induction / drug effects*
  • Fibroblasts / enzymology
  • Gingiva / cytology
  • Gingiva / enzymology*
  • Humans
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / biosynthesis*
  • Isoenzymes / genetics
  • Membrane Proteins
  • Nicotine / toxicity*
  • Nicotinic Agonists / toxicity*
  • Nitrobenzenes / pharmacology
  • Prostaglandin-Endoperoxide Synthases / biosynthesis*
  • Prostaglandin-Endoperoxide Synthases / genetics
  • RNA, Messenger / biosynthesis
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sulfonamides / pharmacology


  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors
  • Isoenzymes
  • Membrane Proteins
  • Nicotinic Agonists
  • Nitrobenzenes
  • RNA, Messenger
  • Sulfonamides
  • N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide
  • Nicotine
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • Prostaglandin-Endoperoxide Synthases