Institut Dr. Schrader Creachem GmbH, Holzminden, Germany.
Skin Pharmacol Physiol. 2011;24(6):300-4. doi: 10.1159/000328736. Epub 2011 Jul 15.
BACKGROUND/AIMS: Topically applied antioxidants (AOs) are widely used in cosmetic products - especially in day and sun care - to help reduce oxidative stress caused by exogenous influences such as ultraviolet (UV) radiation. Despite several advances in recent years, little is known about the duration of protective effects by application of topical AOs, AO protection capacity (APC) or the activation of an endogenous protection capacity (EPC).
By measuring oxidative-stress-induced photon emission of human skin in vivo with the ICL-S method (induced chemiluminescence of human skin), the protective effect of daily AO treatment for 2 weeks was examined on 4 consecutive days after treatment. UVA-dose-independent effects were investigated by decay curve intersection point analysis. In addition, chemiluminescence signal integration was used to investigate the influence of different UVA doses for stimulation on the determined APC as well as the modulation of the EPC by repetitive UVA stimulation both forming the skin protection capacity (SPC).
The SPC showed a strong dependency on the UVA dose used for stimulation. AO pretreatment was more effective against lower UVA doses. Over the course of 4 days, the AO-induced SPC did not change significantly for a given UVA dose. Analyzing the decay curve intersection point for 2 different UVA doses, however, revealed a decrease in SPC with time. In addition, we found that a repetitive UVA irradiation of 1 J/cm(2) caused a statistically significant protective effect against UVA irradiation by stimulation of endogenous mechanisms.
Topically supplemented AOs provide a protective effect against oxidative stress for at least 3 days, supporting their widespread use in cosmetic products. Especially their interaction with cutaneous protective mechanisms should be investigated in more detail for maximal protection, as endogenous defense mechanisms are already triggered by 2 low-dose UVA irradiations within 24 h. In summary, the in vivo measurement of UVA-induced cutaneous chemiluminescence permits the UVA-dose-independent determination of the AO efficacy for better comparability of the results while also taking endogenous defense mechanisms into account.
背景/目的：局部应用的抗氧化剂 (AO) 广泛用于化妆品产品中 - 尤其是日霜和防晒霜 - 以帮助减少由外部因素（如紫外线辐射）引起的氧化应激。尽管近年来取得了一些进展，但对于局部应用 AO 的保护效果持续时间、AO 保护能力 (APC) 或内源性保护能力 (EPC) 的激活知之甚少。
通过使用 ICL-S 方法（人皮肤诱导化学发光）测量人皮肤的氧化应激诱导光发射，在治疗后连续 4 天检查 2 周日常 AO 处理的保护作用。通过衰减曲线交点分析研究了 UVA 剂量无关的影响。此外，使用化学发光信号积分来研究不同 UVA 剂量刺激对确定的 APC 的影响，以及重复 UVA 刺激对 EPC 的调制，这两者共同构成皮肤保护能力 (SPC)。
SPC 强烈依赖于用于刺激的 UVA 剂量。AO 预处理对较低的 UVA 剂量更有效。在 4 天的过程中，对于给定的 UVA 剂量，AO 诱导的 SPC 没有显著变化。然而，分析 2 个不同 UVA 剂量的衰减曲线交点显示 SPC 随时间降低。此外，我们发现 1 J/cm(2)的重复 UVA 照射通过刺激内源性机制引起的保护性作用具有统计学意义。
局部补充的 AO 提供了对氧化应激的保护作用，至少持续 3 天，支持它们在化妆品产品中的广泛应用。特别是应该更详细地研究它们与皮肤保护机制的相互作用，以获得最大的保护效果，因为内源性防御机制在 24 小时内通过 2 次低剂量 UVA 照射已经被触发。总之，UVA 诱导的皮肤化学发光的体内测量允许在不考虑内源性防御机制的情况下，以更好的可比性来确定 AO 的功效，实现 UVA 剂量独立的测定。
