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細胞內(nèi)的活性氮/氧物種類和細胞凋亡在紫外誘導的皮膚炎癥反應中發(fā)揮重要作用。蝦青素，一種葉黃素類型的類胡蘿卜素，在臨床試驗中表現(xiàn)出不同尋常的效果。本文研究了蝦青素對紫外誘導細胞凋亡的作用。蝦青素（5 μm）可以導致蛋白含量、誘導性一氧化氮(iNOS)和環(huán)氧合酶(COX)-2的mRNA顯著下降，同時還可將紫外UVB (20 mJ/cm(2) ) 或UVC (5 mJ/cm(2) )輻射的皮膚表皮角質(zhì)形成細胞釋放的前列腺素E2降低。在預先經(jīng)過蝦青素處理的細胞中沒有觀察到明顯的紫外誘導的活性氧保護作用。根據(jù)DNA斷裂分析的證據(jù)顯示，蝦青素可以顯著抑制紫外照射誘導的細胞凋亡。此外，我們發(fā)現(xiàn)蝦青素處理后可以引起UVB 和 UVC誘導蛋白下降、巨噬細胞移動游走抑制因子mRNA表達量的下調(diào)以及皮膚表皮角質(zhì)形成細胞IL-1β 和TNF-α蛋白的下調(diào)。這些結果表明蝦青素可以有效抑制紫外誘導的炎癥反應，減少誘導型一氧化氮（iNOS）的和環(huán)氧合酶的含量，從而抑制皮膚表皮角質(zhì)形成細胞的凋亡。

Astaxanthin, a xanthophyll carotenoid, inhibits ultraviolet-induced apoptosis in keratinocytesv

Intra-cellular reactive nitrogen/oxygen species and apoptosis play important roles in ultraviolet (UV)-induced inflammatory responses in the skin. Astaxanthin (AST), a xanthophyll carotenoid, exhibits diverse clinical benefits. The protective effects of AST against UV-induced apoptosis were investigated in the present study. Astaxanthin (5 μm) caused a significant decrease in the protein content and the mRNA levels of inducible nitric oxide (iNOS) and cyclooxygenase (COX)-2, and decreased the release of prostaglandin E2 from HaCaT keratinocytes after UVB (20 mJ/cm(2) ) or UVC (5 mJ/cm(2) ) irradiation. No significant protective effects against UV-induced reactive oxygen species (ROS) were observed in AST-pretreated cells. Astaxanthin caused a significant inhibition of UV-irradiation-induced apoptosis, as evidence by a DNA fragmentation assay. Furthermore, we found that the treatment with AST caused a reduction in the UVB- or UVC-induced protein and mRNA expression of macrophage migration inhibitory factor (MIF), IL-1β and TNF-α in HaCaT keratinocytes. These results suggest that AST effectively protects against UV-induced inflammation by decreasing iNOS and COX-2, and thereby inhibiting the apoptosis of keratinocytes.