Inhibition of NF-κB Activation by Pyrrolidine Dithiocarbamate Prevents In Vivo Expression of Proinflammatory Genes

Background-The inability to inhibit multiple mediators of septic shock represents a major hurdle in the treatment of septic shock. In vivo inhibition of nuclear factor (NF)-kappaB activation, a transcription factor regulating expression of many proinflammatory genes, could provide a useful strategy for the treatment of septic shock. Methods and Results-In rats challenged with lipopolysaccharide (LPS) 8 mg/kg IV, we determined the time course of NF-kappaB activation and expression of multiple inflammatory signals: tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase-2 (COX-2), cytokine-inducible neutrophil chemoattractant (CINC), and intercellular adhesion molecule-1 (ICAM)-1. We studied the effects of in vivo inhibition of NF-kappaB activation using pyrrolidine dithiocarbamate (PDTC) on the expression of these mediators. NF-kappaB activation preceded the induction of TNF-alpha, COX-2, CINC, and ICAM-1 mRNAs. PDTC prevented the LPS-induced NF-kappaB activation but did not inhibit activation of the transcription factors AP-1, Sp-1, and CREB. PDTC inhibited the LPS-induced expression of TNF-alpha, COX-2, CINC, and ICAM-1 mRNA and proteins and reduced the LPS-induced increases in plasma TNF-alpha, 6-keto-prostaglandin F(1alpha), and CINC concentrations. Inhibition of expression of these mediators prevented the increases in myeloperoxidase activity (a measure of neutrophil sequestration) in the heart, lungs, and liver. Conclusions-NF-kappaB activation correlates with LPS-induced expression of TNF-alpha, COX-2, CINC, and ICAM-1 genes in vivo. PDTC inhibits NF-kappaB activation and expression of these proinflammatory genes and their products. Thus, blocking NF-kappaB activation may be an effective strategy in the treatment of septic shock.