Department of Dermatology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, P.R. China.
Department of Dermatology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610072, P.R. China.
Mol Med Rep. 2021 Nov;24(5). doi: 10.3892/mmr.2021.12462. Epub 2021 Sep 24.
Vitiligo is a cutaneous depigmentation disorder caused by melanocyte injury or aberrant functioning. Oxidative stress (OS) is considered to be a major cause of the onset and progression of vitiligo. Ginsenoside Rk1 (RK1), a major compound isolated from ginseng, has antioxidant activity. However, whether RK1 can protect melanocytes against oxidative injury remains unknown. The aim of the present study was to investigate the potential protective effect of RK1 against OS in the human PIG1 melanocyte cell line induced with hydrogen peroxide (HO), and to explore its underlying mechanism. PIG1 cells were pretreated with RK1 (0, 0.1, 0.2 and 0.4 mM) for 2 h followed by exposure to 1.0 mM HO for 24 h. Cell viability and apoptosis were determined with Cell Counting Kit‑8 and flow cytometry assays, respectively. The activity levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH‑Px) were analyzed using ELISA kits. Protein expression levels, including Bax, caspase‑3, Bcl‑2, phosphorylated‑AKT, AKT, nuclear factor erythroid 2‑related factor 2 (Nrf2), heme oxygenase‑1 (HO‑1), cytosolic Nrf2 and nuclear Nrf2, were analyzed using western blot analysis. In addition, the expression and localization of Nrf2 were detected by immunofluorescence. RK1 treatment significantly improved cell viability, reduced the apoptotic rate and increased the activity levels of SOD, CAT and GSH‑Px in the PIG1 cell line exposed to HO. In addition, RK1 treatment notably induced Nrf2 nuclear translocation, increased the protein expression levels of Nrf2 and HO‑1, and the ratio of phosphorylated‑AKT to AKT in the PIG1 cells exposed to HO. Furthermore, LY294002 could reverse the protective effect of RK1 in melanocytes against oxidative injury. These data demonstrated that RK1 protected melanocytes from HO‑induced OS by regulating Nrf2/HO‑1 protein expression, which may provide evidence for the application of RK1 for the treatment of vitiligo.
白癜风是一种由黑素细胞损伤或功能异常引起的皮肤色素脱失疾病。氧化应激（OS）被认为是白癜风发病和进展的主要原因。人参皂苷 Rk1（RK1）是从人参中分离得到的主要化合物，具有抗氧化活性。然而，RK1 是否能保护黑素细胞免受氧化损伤尚不清楚。本研究旨在探讨 RK1 对过氧化氢（HO）诱导的人 PIG1 黑素细胞系 OS 的潜在保护作用，并探讨其潜在机制。PIG1 细胞用 RK1（0、0.1、0.2 和 0.4 mM）预处理 2 h 后，用 1.0 mM HO 孵育 24 h。用细胞计数试剂盒-8 和流式细胞术分别测定细胞活力和细胞凋亡。采用 ELISA 试剂盒分析超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH-Px）的活性水平。用 Western blot 分析测定 Bax、caspase-3、Bcl-2、磷酸化 AKT、AKT、核因子红细胞 2 相关因子 2（Nrf2）、血红素加氧酶-1（HO-1）、细胞质 Nrf2 和核 Nrf2 的蛋白表达水平。此外，通过免疫荧光法检测 Nrf2 的表达和定位。RK1 处理显著提高了 HO 暴露的 PIG1 细胞系的细胞活力，降低了细胞凋亡率，并提高了 SOD、CAT 和 GSH-Px 的活性水平。此外，RK1 处理显著诱导了 Nrf2 核易位，增加了 HO 暴露的 PIG1 细胞中 Nrf2 和 HO-1 的蛋白表达水平，以及磷酸化 AKT 与 AKT 的比值。此外，LY294002 可以逆转 RK1 对黑素细胞氧化损伤的保护作用。这些数据表明，RK1 通过调节 Nrf2/HO-1 蛋白表达来保护黑素细胞免受 HO 诱导的 OS，这可能为 RK1 在白癜风治疗中的应用提供证据。
