Antioxidant effect at times subsequent to IκB proteolysis. (A) Effect of posttreatment on TNF-inducible IL-8 mRNA accumulation. Cells were unstimulated or stimulated with 20 ng/mL TNF in the absence or presence of 2% (vol/vol) DMSO. DMSO was administered at the indicated times (before [-] or after [+] TNF administration). (B) Posttreatment with 2% (vol/vol) DMSO has no effect on IκB proteolysis. Cells were unstimulated or stimulated with 20 ng/mL TNF in the absence or presence of 2% (vol/vol) DMSO. DMSO was administered at the indicated times (preceding [-] or succeeding [+] TNF administration). Top panel, Western immunoblot with anti-IκB antibody; bottom panel, Western immunoblot with an anti-β–actin antibody (internal control). (C) Pre or posttreatment with 2% (vol/vol) DMSO has no effect on Rel A DNA binding in EMSA. Cells were unstimulated/stimulated with 20 ng/mL TNF in the absence or presence of 2% (vol/vol) DMSO. DMSO was administered at the indicated times (before [-] or after [+] TNF administration). Nuclei were isolated and subjected to EMSA analysis with a radiolabeled NF-κB site. Only bound complexes are shown.