Inhibition of NF kappa B activation with antioxidants is correlated with reduced cytokine transcription in PTC

We recently reported that inhibition of the transcription factor nuclear fa ctor-kappa B (NF kappa B) with pyrrolidinedithiocarbamate (PDTC) reduced in terstitial monocyte infiltration in rats with proteinuric tubulointerstitia l disease, whereas N-acetylcysteine (NAC) was not effective. Here we invest igate the effects of antioxidants (PDTC, NAG, and quercetin) on NF kappa B activation and cytokine transcription in primacy cultured rat proximal tubu lar epithelial cells (PTC) stimulated with lipopolysaccharide. Antioxidant- mediated inhibition of NF kappa B activation (PDTC, 20-100 mu M; NAG, 100 m M; and quercetin, 50 mu M) diminished the induction of both pro- [interleuk in (IL)-1 beta, tumor necrosis factor-alpha, monocyte chemoattractant prote in-1, macrophage inflammatory protein (MIP)-1 alpha, and MIP-2] and anti-in flammatory (IL-10, transforming growth factor-beta 1) cytokine transcriptio n in PTC (RT-PCR analysis). PDTC and quercetin did not affect PTC viability , but NAC (100 mM) caused a threefold increase in lactate dehydrogenase lea kage (P < 0.001). We conclude that NAC is unable to suppress NF kappa B act ivation in PTC at subtoxic and physiologically relevant concentrations. Fur thermore, antioxidant-mediated inhibition of NF kappa B is correlated with the nonselective reduction of cytokine transcription in activated tubular c ells. These data might explain the protective effects of PDTC-mediated NF k appa B inhibition in tubulointerstitial disease in vivo.