College of Medicine, Medical University of South Carolina, Charleston, SC, USA.
Department of Biomedical Engineering, Marshall University, USA.
J Dermatol Sci. 2021 May;102(2):94-100. doi: 10.1016/j.jdermsci.2021.03.002. Epub 2021 Mar 16.
Skin aging is marked by progressive loss in elastin and collagen that causes wrinkling and sagging of skin. Tropoelastin (TE) is the precursor monomer of elastin secreted by cells that cross-links extracellularly to create functional elastic fibers. Cells maintain the capacity to make TE during the aging process. However, the process of extracellular tropoelastin cross-linking diminishes with age. Others have shown that TE production by cells increases with UV exposure.
We hypothesize that polyphenols may help coacervate cell secreted TE due to its elastin binding property and increase insoluble elastin in human dermal fibroblasts (HDFs). Increase in TE production by short term UV exposure may further improve elastin deposition by polyphenols.
We treated HDFs with polyphenols viz epigallocatechin gallate (EGCG) and pentagalloyl glucose (PGG) either with or without intermittent (UVA, 12 min three times a week) exposure for 3, 7, and 14 days.
Polyphenols increased insoluble elastin deposition several folds as compared to control untreated cells. Furthermore, short UVA light exposure led to several-fold increased TE production in HDFs. Still, UVA exposure alone was unable to increase insoluble elastic fibers. When polyphenols were introduced with UVA exposure, insoluble elastin deposition was further enhanced in HDFs (30-45-fold increase). Polyphenol treatments with UVA exposure also led to increased collagen deposition in cell cultures. Polyphenols also prevented cell oxidation during UVA exposure.
Polyphenols in combination with short exposure to UVA light increase extracellular matrix deposition of elastin and collagen and may improve skin properties.
皮肤衰老的特征是弹性蛋白和胶原蛋白逐渐流失，导致皮肤出现皱纹和松弛。原弹性蛋白（TE）是细胞分泌的弹性蛋白前体单体，它在细胞外交联形成功能性弹性纤维。细胞在衰老过程中仍保持制造 TE 的能力。然而，细胞外原弹性蛋白交联的过程会随着年龄的增长而减少。其他人已经表明，细胞产生的 TE 会随着 UV 暴露的增加而增加。
我们假设多酚可能通过其与弹性蛋白结合的特性帮助凝聚细胞分泌的 TE，并增加人真皮成纤维细胞（HDFs）中的不溶性弹性蛋白。短期 UV 暴露引起的 TE 产生增加可能进一步改善多酚对弹性蛋白的沉积。
我们用多酚（表没食子儿茶素没食子酸酯（EGCG）和五没食子酰葡萄糖（PGG））处理 HDFs，无论是单独处理还是与间歇性（UVA，每周三次，每次 12 分钟）暴露一起处理，持续 3、7 和 14 天。
与未经处理的对照细胞相比，多酚使不溶性弹性蛋白沉积增加了数倍。此外，短时间的 UVA 光照射导致 HDFs 中 TE 的产生增加了数倍。然而，单独的 UVA 暴露本身并不能增加不溶性弹性纤维。当将多酚与 UVA 暴露一起引入时，HDFs 中的不溶性弹性蛋白沉积进一步增强（增加 30-45 倍）。用 UVA 暴露处理多酚还导致细胞培养物中胶原蛋白沉积增加。多酚还可以防止 UVA 暴露期间细胞氧化。
多酚与短时间的 UVA 光照射相结合，可增加细胞外基质中弹性蛋白和胶原蛋白的沉积，从而改善皮肤特性。
