Yang Keda, Pei Lei, Zhou Siming, Tao Lin, Zhu Yue
Department of Orthopedics, First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.
Exp Ther Med. 2021 Nov;22(5):1316. doi: 10.3892/etm.2021.10751. Epub 2021 Sep 17.
Osteoporosis is a common metabolic disease that has a high incidence in postmenopausal women. Studies have indicated that oxidative damage plays an important role in the development of postmenopausal osteoporosis. Metformin has been showed to have the ability to relieve excessive oxidation. The aim of the present was to determine the therapeutic effect and potential mechanism of metformin in postmenopausal osteoporosis. Oxidative damage was stimulated by the addition of HO to MC3T3-E1 cells and a mouse menopausal model was also constructed. Cell viability and flow cytometry experiments were performed to determine the effects of HO and metformin treatment on apoptosis. Mitochondrial membrane potential was tested by JC-1 assays. Western blotting was used to detect the expression of mitochondrial apoptosis markers and antioxidant enzymes. Small interfering RNA was used to knockdown sirtuin3 (SIRT3), which was verified at the mRNA and protein levels. Bilateral ovariectomy was used to prepare menopausal mice, which were analyzed using micro-computed tomography. The results indicated that metformin is able to repair mitochondrial damage and inhibit the apoptosis of osteoblasts induced by HO, and also reverse bone mass loss in ovariectomized mice. Western blotting results demonstrated the involvement of SIRT3 in the production of antioxidant enzymes that are essential in protecting against mitochondrial injury. In addition, experiments with SIRT3 knockdown indicated that metformin reverses HO-induced osteoblast apoptosis by upregulating the expression of SIRT3 via the PI3K/AKT pathway. The results of the present reveal the pathogenesis of oxidative damage and the therapeutic effect of metformin in postmenopausal osteoporosis. They also suggest that SIRT3 is a potential drug target in the treatment of osteoporosis, with metformin being a candidate drug for modification and/or clinical application.
骨质疏松症是一种常见的代谢性疾病，在绝经后女性中发病率较高。研究表明，氧化损伤在绝经后骨质疏松症的发生发展中起重要作用。二甲双胍已被证明具有减轻过度氧化的能力。本研究的目的是确定二甲双胍在绝经后骨质疏松症中的治疗效果及潜在机制。通过向MC3T3-E1细胞中添加过氧化氢（HO）来诱导氧化损伤，并构建小鼠绝经模型。进行细胞活力和流式细胞术实验以确定HO和二甲双胍处理对细胞凋亡的影响。通过JC-1检测法检测线粒体膜电位。采用蛋白质免疫印迹法检测线粒体凋亡标志物和抗氧化酶的表达。使用小干扰RNA敲低沉默调节蛋白3（SIRT3），并在mRNA和蛋白质水平进行验证。采用双侧卵巢切除术制备绝经小鼠，并使用微型计算机断层扫描进行分析。结果表明，二甲双胍能够修复线粒体损伤，抑制HO诱导的成骨细胞凋亡，还能逆转去卵巢小鼠的骨量丢失。蛋白质免疫印迹结果表明，SIRT3参与了抗氧化酶的产生，而抗氧化酶对于保护线粒体免受损伤至关重要。此外，SIRT3敲低实验表明，二甲双胍通过PI3K/AKT途径上调SIRT3的表达，从而逆转HO诱导的成骨细胞凋亡。本研究结果揭示了氧化损伤的发病机制以及二甲双胍在绝经后骨质疏松症中的治疗作用。研究还表明，SIRT3是骨质疏松症治疗的潜在药物靶点，二甲双胍是一种可供改良和/或临床应用的候选药物。
