Silica-induced pulmonary inflammation in rats: Activation of NF-κB and its suppression by dexamethasone

Meir Sacks, John Gordon, John Bylander, Dale Porter, X. L. Shi, Vincent Castranova, Walter Kaczmarczyk, Knox Van Dyke, Mark J. Reasor

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


The goal of this study was to examine the relationship of the transcriptional regulatory factor nuclear factor-kappaB (NF-κB) to the early inflammatory events involved with silica exposure. Male F-344 rats received an intratracheal (i.t.) instillation of silica (100 mg/kg in a volume of 1 ml/kg) of saline. At 1, 3, 6, and 18 h postinstillation, and the rats were sacrificed and underwent bronchoalveolar lavage (BAL) for functional analysis of inflammation. Beginning at 1 h postinstillation, the silica-instilled (Si) rats displayed significant increases in neutrophils in BAL fluid compared to the saline controls. BAL cells from the Si group displayed a significant increase in luminol-dependent chemiluminescence (LDCL) compared to the controls. NF-κB activation was measurable at 3 h postinstillation, and this activation continued throughout the 18-h time course. Treatment with dexamethasone (5 mg/kg) at -3 h prior to silica instillation, at the time of instillation (0 h), and +1.5 h postinstillation resulted in both a reduction in NF-κB expression (by 70%) at 3 h postinstillation and corresponding reductions in LDCL, BAL cell count, and BAL neutrophils. These results show that activation of NF-κB is associated with silica-induced pulmonary inflammation, and the inhibition of its activation correlates temporally with suppression of inflammation.

Original languageEnglish
Pages (from-to)181-184
Number of pages4
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - Dec 9 1998

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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