Vanillin suppresses Kupffer cell-related colloidal carbon-induced respiratory burst activity in isolated perfused rat liver: anti-inflammatory implications

Abstract

The inhibition of NADPH oxidase has become a potential therapeutic target for oxidative stress-related diseases. We investigated whether vanillin modifies hepatic O₂ consumption associated with Kupffer cell functioning. The influence of vanillin on Kupffer cell functioning was studied in isolated perfused rat liver by colloidal carbon (CC) infusion (0.5 mg ml⁻¹), concomitantly with sinusoidal efflux of lactate dehydrogenase (LDH) as an organ viability parameter. CC infusion increased the rate of O₂ consumption of the liver above basal values, an effect that represents the respiratory burst activity of Kupffer cells. However, CC-dependent respiratory burst activity was suppressed by previous infusion of 2 mM vanillin. Vanillin did not affect the liver CC uptake rate and liver sinusoidal efflux of LDH efflux. These findings, elicited by vanillin, were reproduced by the well-established NADPH oxidase inhibitor apocynin. In conclusion, vanillin suppresses the respiratory burst activity of Kupffer cells as assessed in intact liver, which may be associated with the inhibition of macrophage NADPH oxidase activity. Such a finding may have relevance in conditions underlying Kupffer cell-dependent up-regulation of the expression and release of pro-inflammatory mediators by redox-dependent mechanisms.