Expression of Cytokines and Activation of Transcription Factors in Lipopolysaccharide-Administered Rats and Their Inhibition by PhenylN-tert-Butylnitrone (PBN)

The spin-trapping compound phenylN-tert-butylnitrone (PBN) affords protection from the lethality of septic shock in rodents. Previous studies have shown that PBN elicits its protection by inhibiting inducible nitric oxide synthase (iNOS) induction. In the present study, using the lipopolysaccharide (LPS) rat septic shock model, we determined the expression of various cytokine genes (tumor necrosis factor (TNF)-α, TNF-β, interferon (IFN)-γ, interleukin (IL)-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, and IL-10) and the activation of transcription factors nuclear factor κB (NF-κB) and activator protein-1 (AP-1) in the liver tissue, 30 min and 3 h after LPS administration. The effects of PBN preadministration on the production levels were also investigated. The results show that LPS (4 mg/kg, ip) induced the production of the cytokine genes and increased the nuclear protein level of NF-κB within 30 min after LPS administration. Preadministration of PBN (150 mg/kg, ip) significantly down-regulated the production of cytokine genes (TNF-α by 94%, IL-1 by 63%, and IL-1 by 70%) and reduced the nuclear protein level of NF-κB by 75% and AP-1 by 72% at 3 h after LPS injection. These results demonstrate that PBN, in addition to its iNOS induction inhibition, also has multiple anti-inflammatory effects in septic shock, via modulation of the production of the key inflammatory mediators.