Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
Department of Orthopedics, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
IUBMB Life. 2022 Nov;74(11):1052-1069. doi: 10.1002/iub.2656. Epub 2022 Jun 11.
Growing evidence indicates that iron overload is an independent risk factor for osteoporosis. However, the mechanisms are not fully understood. The purpose of our study was to determine whether iron overload could lead to ferroptosis in osteoblasts and to explore whether ferroptosis of osteoblasts is involved in iron overload-induced osteoporosis in vitro and in vivo. Ferric ammonium citrate was used to mimic iron overload conditions, while deferoxamine and ferrostatin-1 were used to inhibit ferroptosis of MC3T3-E1 cells in vitro. The ferroptosis, osteogenic differentiation and mineralization of MC3T3-E1 cells were assessed in vitro. A mouse iron overload model was established using iron dextran. Immunohistochemical analysis was performed to determine ferroptosis of osteoblasts in vivo. Enzyme-linked immunosorbent assays and calcein-alizarin red S labelling were used to assess new bone formation. Dual x-ray absorptiometry, micro-computed tomography and histopathological analysis were conducted to evaluate osteoporosis. The results showed that iron overload reduced cell viability, superoxide dismutase and glutathione levels, increased reactive oxygen species generation, lipid peroxidation, malondialdehyde levels and ferroptosis-related protein expression, and induced ultrastructural changes in mitochondria. Iron overload could also inhibit osteogenic differentiation and mineralization in vitro. Inhibiting ferroptosis reversed the changes described above. Iron overload inhibited osteogenesis, promoted the ferroptosis of osteoblasts and induced osteoporosis in vivo, which could also be improved by deferoxamine and ferrostatin-1. These results demonstrate that ferroptosis of osteoblasts plays a crucial role in iron overload-induced osteoporosis. Maintaining iron homeostasis and targeting ferroptosis of osteoblasts might be potential measures of treating or preventing iron overload-induced osteoporosis.
越来越多的证据表明，铁过载是骨质疏松症的一个独立危险因素。然而，其机制尚未完全阐明。本研究旨在确定铁过载是否会导致成骨细胞发生铁死亡，并探讨成骨细胞铁死亡是否参与铁过载诱导的体外和体内骨质疏松症。使用柠檬酸铁铵模拟铁过载条件，同时使用去铁胺和 ferrostatin-1 抑制 MC3T3-E1 细胞的铁死亡。体外评估 MC3T3-E1 细胞的铁死亡、成骨分化和矿化。使用右旋糖酐铁建立小鼠铁过载模型。免疫组织化学分析用于确定体内成骨细胞的铁死亡。酶联免疫吸附试验和 calcein-alizarin red S 标记用于评估新骨形成。双能 X 线吸收法、微计算机断层扫描和组织病理学分析用于评估骨质疏松症。结果表明，铁过载降低细胞活力、超氧化物歧化酶和谷胱甘肽水平，增加活性氧生成、脂质过氧化、丙二醛水平和铁死亡相关蛋白表达，并诱导线粒体超微结构改变。铁过载还可抑制体外成骨分化和矿化。抑制铁死亡可逆转上述变化。铁过载抑制成骨作用，促进成骨细胞铁死亡，并诱导体内骨质疏松症，去铁胺和 ferrostatin-1 可改善这种情况。这些结果表明，成骨细胞铁死亡在铁过载诱导的骨质疏松症中起关键作用。维持铁平衡和靶向成骨细胞铁死亡可能是治疗或预防铁过载诱导的骨质疏松症的潜在措施。
