No.3 People's Hospital/Shanghai Jiao-Tong University School of Medicine (SJTU-SM), Shanghai, China.
Australas J Dermatol. 2012 Aug;53(3):172-80. doi: 10.1111/j.1440-0960.2012.00912.x. Epub 2012 Jun 27.
BACKGROUND/OBJECTIVES: Free radicals and reactive oxygen species (ROS), which are generated by UV irradiation, may induce an irreversible growth arrest similar to senescence. Tiron, 4,5-dihydroxy-1,3-benzene disulfonic acid, is a widely used antioxidant to rescue ROS-evoked cell death. The aim of the article was to explore the effects of tiron on skin photoaging and associated mechanisms.
The effects of tiron on cell proliferation were determined using 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide. Senescent cells were determined by morphology and senescence-associated β-galactosidase activity analysis. Intracellular hydrogen peroxide, superoxide anion and glutathione concentration were analysed by a fluorescent probe. The concomitant changes of protein expression were analysed with Western blot.
Human dermal fibroblasts were induced to premature senescence by sub-cytotoxic doses of irradiated UVB. Strong senescence-associated β-galactosidase activity and increased intracellular superoxide anion were observed in human dermal fibroblasts irradiated by UVB. Tiron blocks UVB-induced glutathione depletion and increase of superoxide anion and protects against UVB-induced senescence-like characteristics in human dermal fibroblasts. Compared with normal fibroblasts, UVB-irradiated human dermal fibroblasts showed a higher ratio of active (hypophosphorylated) to inactive (phosphorylated) forms of Rb and p38, upregulation of p53 or p16 and c-Myc and insulin-like growth factor 1 (IGF-1) downregulation. After treatment with tiron, p53, p16 c-Myc and IGF-1 as well as phosphorylation Rb and p38 could partially recover.
These results indicate that tiron protects against UVB-induced senescence-like characteristics in human dermal fibroblasts via the inhibition of production of superoxide anion and glutathione depletion, and modulation of related senescence proteins.
背景/目的：自由基和活性氧（ROS）是由紫外线照射产生的，可能会诱导类似于衰老的不可逆生长停滞。Tiron（4,5-二羟基-1,3-苯二磺酸）是一种广泛用于拯救 ROS 诱导细胞死亡的抗氧化剂。本文旨在探讨 Tiron 对皮肤光老化的影响及其相关机制。
使用 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐测定 Tiron 对细胞增殖的影响。通过形态学和衰老相关β-半乳糖苷酶活性分析确定衰老细胞。通过荧光探针分析细胞内过氧化氢、超氧阴离子和谷胱甘肽浓度。用 Western blot 分析蛋白表达的伴随变化。
亚细胞毒性剂量的照射 UVB 可诱导人真皮成纤维细胞过早衰老。UVB 照射的人真皮成纤维细胞中观察到强烈的衰老相关β-半乳糖苷酶活性和细胞内超氧阴离子增加。Tiron 可阻断 UVB 诱导的谷胱甘肽耗竭和超氧阴离子增加，并防止 UVB 诱导的人真皮成纤维细胞衰老样特征。与正常成纤维细胞相比，UVB 照射的人真皮成纤维细胞中活性（低磷酸化）形式与非活性（磷酸化）形式的 Rb 和 p38 的比例更高，p53 或 p16 和 c-Myc 上调，胰岛素样生长因子 1（IGF-1）下调。用 Tiron 处理后，p53、p16、c-Myc 和 IGF-1 以及 Rb 和 p38 的磷酸化可部分恢复。
这些结果表明，Tiron 通过抑制超氧阴离子的产生和谷胱甘肽耗竭，以及调节相关衰老蛋白，防止 UVB 诱导的人真皮成纤维细胞衰老样特征。
