Effect of the 21-aminosteroid on nuclear factor-kappa B activation of Kupffer cells in endotoxin shock

The 21-aminosteroid (U-74389G) is a nonglucocorticoid steroid that was synthesized to inhibit lipid peroxidation without the glucocorticoid activity. We recently demonstrated that the 21-aminosteroid administered to endotoxin shock mice reduces liver injury and improves the survival rate of mice through inhibition of nuclear factor-kappa B activation in the liver. The study was undertaken to determine whether the 21-aminosteroid could suppress pro-inflammatory gene up-regulation through inhibition of nuclear factor-kappa B activation in Kupffer cells.

Kupffer cells were isolated from rats by collagenase perfusion followed by pronase digestion. After a lipopolysaccharide addition, each assay was performed for tumor necrosis factor-alpha, interleukin-6, tumor necrosis factor-alpha messenger RNA, nuclear factor-kappa B, and I kappa B proteins.

After the lipopolysaccharide addition, Kupffer cells released both tumor necrosis factor-alpha and interleukin-6. The 21-aminosteroid treatment suppressed the release of tumor necrosis factor-alpha in a dose-dependent manner. The 21-aminosteroid also inhibited the increase of tumor necrosis factor-alpha messenger RNA expression and nuclear factor-kappa B activation in Kupffer cells 1 hour and 30 minutes, respectively, after lipopolysaccharide addition. Furthermore, the 21-aminosteroid treatment suppressed the degradation of I kappa B proteins in lipopolysaccharide-stimulated Kupffer cells.

These results suggest that the 21-aminosteroid inhibits release of the tumor necrosis factor-alpha and interleukin-6 from lipopolysaccharide-stimulated Kupffer cells by inhibiting nuclear factor-kappa B activation. This is accomplished by inhibiting I kappa B degradation in endotoxin shock and this may prove useful for the treatment of endotoxin shock.