Repeated low-dose ultraviolet (UV) B exposures of humans induce limited photoprotection against the immune effects of erythemal UVB radiation

Abstract

The repeated low doses of UVB protected to a limited extent against the effects of an erythemal UVB dose on cytokine expression and thymine dimer formation, but not on CHS or COX enzymes.

Differential modulation of inflammatory markers in plasma and skin after single exposures to UVA or UVB radiation in vivo

“…Nevertheless in human keratinocytes, Buckman et al found a moderate COX-2 protein increase at 6 h and strong one at 24 h after UVB (290-320 nm, 30 mJ/cm 2 ) exposure 36 . Narbutt et al also found a massive increase of COX-2 expression in human skin 24 h after a single exposure to 3 MED as well as repeated (10 x 0.7 MED) of UVB (280-315 nm) (ref 17 ). Similarly, Rhodes et al reported up-regulated COX-2 level in human skin 24 h after UV exposure (290-400 nm, peak 313 nm) but not at 4 and 72 h (ref.…”

“…Local exposure of human volunteers to SSL (1 and 3 MED) induced a strong increase in IL-10 mRNA level 24 h after exposure 13 . Narbutt et al found enhanced IL-10 mRNA level in skin 17 but unchanged protein level in plasma 18 at 24 h after a single exposure to 3 MED of UVB (280-315 nm) exposure. In UVA irradiated mice, we found a significant IL-10 increase in both plasma and skin samples after 24 h. Shen et al reported that UVA (37.8 J/cm 2 ) irradiation caused non-significant but detectable increase in IL-10 level in mice skin during 0-120 h after exposure 25 .…”

“…Narbutt et al found increased mRNA levels of IL-1β and TNF-α in human skin 24 h after a single local UVB (280-315 nm) exposure of 3 MED (ref. 17 ). In contrast, no significant changes in TNF-α and IL-1β level were found in plasma of human subjects at 24 h following a single exposure to 3 MED of UVB (280-315 nm).…”

“…In contrast, massive increase in IL-6 mRNA level was found in human skin 24 h after a single exposure to 3 MED of UVB (280-315 nm) (ref. 17 ). Similarly, repeated SSL (280-400 nm; 96% UVA) exposures (10 x 120 J/m 2 ) caused a significant increase in mRNA levels of IL-6 in human skin 19 .…”

Fotoimmünoloji

“…Tekrarlayan düşük dozda UVB uygulandığında difenilsiklopropenona (DPCP) bağlı kontakt hipersensitivite yanıtında anlamlı derecede azalma geliştiği gösterilirken, kutanöz IL-1beta, IL-6, IL-10, TNF-alfa mRNAs, COX-1, COX-2 ve timin dimerlerinde ise artış olur. Tek doz düşük doz UVB uygulamasında ise bu sitokin düzeylerinde hafifçe bir azalma ortaya çıkmaktadır 5 . Düşük dozda UVA'nın kontakt hipersesitivite üzerine bir etkisi yoktur 6 .…”