Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University (Jiangsu Province Hospital), No. 300 Guangzhou Road, Nanjing, 210029, Jiangsu Province, China.
J Orthop Surg Res. 2024 Jan 3;19(1):23. doi: 10.1186/s13018-023-04483-0.
Osteoarthritis (OA) is a common degenerative disease involving articular cartilage, in which ferroptosis of chondrocytes plays an important role. Baicalin (BAI) exerts regulatory effects in a wide range of orthopedic diseases including OA, but its effect on ferroptosis of chondrocytes (CHs) is still unclear. The purpose of this study was to determine the effect of BAI on ferroptosis in human OA chondrocytes (OACs), and to explore its possible mechanism.
CHs were treated with IL-1β (10 ng/mL) to simulate inflammation in vitro. Immunofluorescence, quantitative RT-PCR, Western blotting and cell viability assay were performed to evaluate the impacts of BAI on Fe level, mitochondrial dysfunction, ferroptosis-related proteins, oxidative stress and cytotoxicity in CHs. Additionally, siRNA was made use of to knock out nuclear factor E2-related factor 2 (Nrf2) to analyze the role played by Nrf2 in BAI-induced CH ferroptosis.
BAI eliminated IL-1β-induced Fe accumulation, changes in mitochondrial membrane potential and ferroptosis-related protein GPX4, SLC7A11, P53 and ACSL4 levels, as well as reactive oxygen species (ROS), lipid peroxidation (LPO) and malondialdehyde (MDA) accumulation in CHs. Besides, BAI reversed IL-1β-induced decrease of Collagen II and increase of MMP13 in CHs. Meanwhile, BAI attenuated IL-1β-induced CH toxicity and promoted Nrf2 antioxidant system activation. When Nrf2 was knocked down by siRNA, the effects of BAI on IL-1β-induced ferroptosis-related proteins and antioxidant stress in CHs were significantly weakened.
This study demonstrates that IL-1β can induce CH ferroptosis. BAI is able to inhibit IL-1β-induced CH ferroptosis and ECM degradation, and the specific mechanism may be that it can inhibit IL-1β-induced CH ferroptosis by activating Nrf2 antioxidant system to attenuate the accumulation of intracellular ROS and lipid ROS.
骨关节炎（OA）是一种常见的关节软骨退行性疾病，其中软骨细胞的铁死亡起着重要作用。黄芩苷（BAI）在包括 OA 在内的多种骨科疾病中发挥着调节作用，但它对软骨细胞（CHs）铁死亡的影响尚不清楚。本研究旨在确定 BAI 对人 OA 软骨细胞（OACs）铁死亡的影响，并探讨其可能的机制。
用白细胞介素-1β（10ng/mL）处理 CHs 以体外模拟炎症。通过免疫荧光、定量 RT-PCR、Western blot 和细胞活力测定评估 BAI 对 CHs 中铁水平、线粒体功能障碍、铁死亡相关蛋白、氧化应激和细胞毒性的影响。此外，利用 siRNA 敲除核因子 E2 相关因子 2（Nrf2），分析 Nrf2 在 BAI 诱导的 CH 铁死亡中的作用。
BAI 消除了 IL-1β诱导的 CH 中铁积累、线粒体膜电位变化以及铁死亡相关蛋白 GPX4、SLC7A11、P53 和 ACSL4 水平的变化，以及活性氧（ROS）、脂质过氧化（LPO）和丙二醛（MDA）的积累。此外，BAI 逆转了 IL-1β诱导的 CH 中 Collagen II 减少和 MMP13 增加。同时，BAI 减轻了 IL-1β诱导的 CH 毒性，并促进了 Nrf2 抗氧化系统的激活。当用 siRNA 敲低 Nrf2 时，BAI 对 CH 中 IL-1β诱导的铁死亡相关蛋白和抗氧化应激的作用明显减弱。
本研究表明，IL-1β可诱导 CH 铁死亡。BAI 能够抑制 IL-1β诱导的 CH 铁死亡和 ECM 降解，其具体机制可能是通过激活 Nrf2 抗氧化系统抑制 IL-1β诱导的 CH 铁死亡，从而减轻细胞内 ROS 和脂质 ROS 的积累。
