Seité Sophie, Reinhold Katja, Jaenicke Thomas, Brenden Heidi, Krutmann Jean, Grether-Beck Susanne
La Roche-Posay Pharmaceutical Laboratories, Asnières, France.
Cutis. 2012 Dec;90(6):321-6.
The damaging effects of UVA radiation have been well-documented. UVA radiation is known to induce molecular, cellular, and clinical damage. Such harm may lead to photoaging, immune system depression, altered gene expression, or oncogene and tumor suppressor gene modulation, all of which are partly responsible for the development of skin cancer. In parallel to an increased understanding of the added damage caused by UVA radiation, progress has been made in sunscreen formulation. A variety of UVA filters are now available for formulators to combine with UVB filters to reach high-level photostable protection using a minimum concentration of active ingredients. The efficacy of products that contain these UV filter combinations usually is determined by noninvasive assessments, which cause either UVA-induced erythema or skin pigmentation. However, the biologic relevance of these end points for UVA radiation-induced skin damage is unknown. In our study, we confirm that the assessment of UVA radiation-induced gene expression in skin specimens obtained from UVA-irradiated human skin by quantitative real-time polymerase chain reaction is a sensitive, reliable, and robust method to prove the efficacy of 2 daily moisturizers containing broad-spectrum sunscreen. Specifically, we demonstrate in vivo that topical application of a daily moisturizer with broad-spectrum sunscreen prevents UVA radiation-induced transcriptional expression of genes that are directly linked to skin aging (ie, matrix metalloproteinase 1 [MMP-1]) and also reflect the skin's antioxidative stress defense response (ie, catalase [CAT], superoxide dismutase [SOD], glutathione peroxidase [GPx]). Furthermore, we demonstrate that the protection against UV-induced skin damage provided by products with different sun protection factor (SPF) but the same UVA protection factor (UVA-PF) is similar, which emphasizes the importance of high UVA protection to maintain unaltered essential biologic functions. These data indicate that the use of a daily moisturizer containing broad-spectrum sunscreen with a well-balanced SPF/UVA-PF ratio on a regular basis is beneficial for human skin.
UVA辐射的破坏作用已有充分记录。已知UVA辐射会引发分子、细胞及临床层面的损伤。此类损害可能导致光老化、免疫系统抑制、基因表达改变，或原癌基因与抑癌基因调控，所有这些在一定程度上都与皮肤癌的发生有关。随着对UVA辐射所造成的额外损害的认识不断加深，防晒配方也取得了进展。现在有多种UVA滤光剂可供配方师与UVB滤光剂结合使用，以最低浓度的活性成分实现高水平的光稳定防护。含有这些UV滤光剂组合的产品功效通常通过非侵入性评估来确定，这些评估会引发UVA诱导的红斑或皮肤色素沉着。然而，这些终点对于UVA辐射诱导的皮肤损伤的生物学相关性尚不清楚。在我们的研究中，我们证实通过定量实时聚合酶链反应评估从UVA照射的人体皮肤获取的皮肤标本中UVA辐射诱导的基因表达，是一种灵敏、可靠且稳健的方法，可用于证明两款含广谱防晒剂的日常保湿霜的功效。具体而言，我们在体内证明，局部涂抹含广谱防晒剂的日常保湿霜可防止UVA辐射诱导与皮肤老化直接相关的基因（即基质金属蛋白酶1 [MMP-1]）的转录表达，同时也反映了皮肤的抗氧化应激防御反应（即过氧化氢酶 [CAT]、超氧化物歧化酶 [SOD]、谷胱甘肽过氧化物酶 [GPx]）。此外，我们证明具有不同防晒系数（SPF）但相同UVA防护系数（UVA-PF）的产品对紫外线诱导的皮肤损伤的防护效果相似，这强调了高UVA防护对于维持基本生物学功能不变的重要性。这些数据表明，定期使用含广谱防晒剂且SPF/UVA-PF比例均衡得当的日常保湿霜对人体皮肤有益。
