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Abstract：
Glucosamine (GlcN) is the most used supplement for osteoarthritis treatment. In vitro studies have related GlcN to beneficial and detrimental effects on health. The aim of this study was to evaluate the effects of O-linked-N-acetylglucosaminylation (O-GlcNAc) on GlcN-induced ROS production and Nrf2 expression in human dermal microvascular endothelial cells-1 (HMEC-1) and to evaluate the antioxidant capacity of GlcN compared to well-known antioxidants. For this, we evaluate the antioxidant capacity by in vitro assays. Besides, the GlcN (5-20 mM) effects on cell viability, reactive oxygen species (ROS) production, O-GlcNAc, and nuclear factor erythroid-2-related factor 2 (Nrf2) expression with and without the O-GlcNAc inhibitor OSMI-1 (10 μM) in HMEC-1 were evaluated. GlcN showed high inhibitory concentration (low scavenging activity) against superoxide (O2•─, IC20 = 47.67 mM), 2,2-diphenyl-1-picrylhydrazyl (DPPH•, IC50 = 21.32 mM), and hydroxyl (HO•, IC50 = 14.04 mM) radicals without scavenging activity against hydrogen peroxide (H2O2) and low antioxidant capacity determined by oxygen radical absorbance capacity (ORAC, 0.001 mM Trolox equivalent) and ferric reducing antioxidant power (FRAP, 0.046 mM Trolox equivalent). In cell culture, GlcN (20 mM) reduced cell viability up to 26 % and induced an increase in ROS production (up to 70 %), O-GlcNAc (4-fold-higher vs. control), and Nrf2 expression (56 %), which were prevented by OSMI-1. These data suggest an association between O-GlcNAc, ROS production, and Nrf2 expression in HMEC-1 cells stimulated with GlcN.
摘要：
氨基葡萄糖（GlcN）是骨关节炎治疗最常用的补充剂。体外研究已经将GlcN与对健康的有益和有害影响相关联。这项研究的目的是评估O-连接-N-乙酰氨基葡萄糖化（O-GlcNAc）对人真皮微血管内皮细胞-1（HMEC-1）中GlcN诱导的ROS产生和Nrf2表达的影响，并评估GlcN与众所周知的抗氧化剂相比的抗氧化能力。为此，我们通过体外试验评估抗氧化能力。此外,GlcN（5-20mM）对细胞活力的影响，活性氧（ROS）的产生，O-GlcNAc,在HMEC-1中有和没有O-GlcNAc抑制剂OSMI-1（10μM）的情况下，评估了核因子红细胞相关因子2（Nrf2）的表达。GlcN对超氧化物（O2·─，IC20=47.67mM），2,2-二苯基-1-吡啶酰肼(DPPH•，IC50=21.32mM),和羟基(HO·，IC50=14.04mM）对过氧化氢（H2O2）没有清除活性的自由基和由氧自由基吸收能力确定的低抗氧化能力（ORAC，0.001mMTrolox当量）和三价铁还原抗氧化能力（FRAP，0.046mMTrolox当量)。在细胞培养中,GlcN（20mM）降低细胞活力高达26％，并诱导ROS产生增加（高达70％），O-GlcNAc（比control),和Nrf2表达（56%），由OSMI-1阻止。这些数据表明O-GlcNAc之间存在关联，ROS生产，和在用GlcN刺激的HMEC-1细胞中Nrf2表达。
