Induction of tumor necrosis factor-alpha by UVB: a role for reactive oxygen intermediates and eicosanoids.

UVB irradiation induces nuclear factor-kappaB (NF-kappaB) activation, tumor necrosis factor-alpha (TNF-alpha) expression and reactive oxygen intermediates (ROI) in keratinocytes. We investigated whether ROI play a role in UVB-induced TNF-alpha mRNA expression. The antioxidants N-acetyl cysteine, NAC, epigallocathin gallate, EGCG, butylated hydroxyanisole (BHA) and vitamin C could reduce UVB-induced TNF-alpha mRNA levels to various degrees; vitamin E (alpha-tocopherol) had no effect.

Eicosapentaenoic acid, a n-3 polyunsaturated fatty acid differentially modulates TNF-alpha, IL-1alpha, IL-6 and PGE2 expression in UVB-irradiated human keratinocytes.

In response to UVB-irradiation keratinocytes release a variety of cytokines and prostaglandins, including tumor necrosis factor alpha (TNF-alpha), interleukin 1alpha (IL-1alpha), interleukin 6 (IL-6), and prostaglandin E2 (PGE2). n-3 Polyunsaturated fatty acids (PUFA), mainly present in fish oil, can modulate cytokine synthesis, as predominantly studied in macrophages. In order to investigate the immune modulating actions of n-3 PUFA on the UVB response in human skin, we investigated the effect of eicosapentaenoic acid (EPA), a n-3 PUFA and a precursor of eicosanoid biosynthesis, on UVB-modulated TNF-alpha, IL-1alpha, IL-6, and PGE2 expression in normal human keratinocytes (NHK).