NF-kappaB is involved in inhibition of lipoxin A4 on dermal inflammation and hyperplasia induced by mezerein.

The mechanisms by which lipoxin A(4) (LXA(4)) inhibit skin inflammation remain unclear. In the present studies, the ear inflammatory model was induced by topical application of mezerein. Treatment of the mouse ear with LXA(4) exhibited the inhibitory effects on oedema, neutrophil infiltration, vascular permeability, expressions of interleukin (IL)-1, IL-6 and IL-8 mRNA, DNA-binding activity of nuclear factor-kappaB (NF-kappaB), and on dermal hyperplasia. NF-kappaB reporter activities and nuclear translocations of NF-kappaB p65 in cultured keratinocytes stimulated by mezerein were inhibited by pretreatment of the cells with LXA(4). LXA(4) reduced degradation, but not phosphorylation of IkappaBalpha in cultured keratinocytes stimulated by mezerein, suggesting that LXA(4)-attenuated IkappaBalpha degradation may restore the mezerein-blocked inhibitory effects of IkappaB on nuclear translocation and DNA-binding activity of NF-kappaB. Our results demonstrated that LXA(4) displays the anti-inflammatory and anti-proliferative role on ear inflammatory model induced by mezerein and these effects were related with downregulation of DNA-binding activity of NF-kappaB.