Department of Implantology, School and Hospital of Stomatology, Shandong University, Shandong Key Laboratory of Oral Tissue Regeneration and Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, Shandong 250012, P.R. China.
Department of Prothodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China.
Mol Med Rep. 2020 Jul;22(1):257-264. doi: 10.3892/mmr.2020.11094. Epub 2020 Apr 24.
The incidence of peri-implant bone loss is high, and is a difficult condition to treat. Previous studies have shown that titanium (Ti) ions released from implants can lead to osteoblast cell damage, but the specific mechanisms have not been elucidated. The present study established a Ti ion damage osteoblast cell model. The levels of mitochondrion‑derived reactive oxygen species (mROS) and autophagy, cell viability and the sirtuin 3 (SIRT3)/superoxide dismutase 2 (SOD2) pathway were examined in this model. It was found that Ti ions decreased osteoblast viability. Moreover, with increased Ti ion concentration, the expression levels of microtubule associated protein 1 light chain 3α (LC3) progressively increased, P62 decreased, autophagic flow increased and mROS levels increased. After the addition of an autophagy inhibitor Bafilomycin A1 and Mito‑TEMPO, a mitochondrial antioxidant, the production of mROS was inhibited, the level of autophagy was decreased and cell activity was improved. In addition, with increased Ti ion concentration, the activity of SOD2 decreased, the acetylation level of SOD2 increased, the SIRT3 mRNA and protein expression levels decreased, and the activity of SIRT3 was significantly decreased. Furthermore, it was demonstrated that SIRT3 overexpression reduced the acetylation of SOD2 and increased the activity of SOD2, as well as reducing the production of mROS and the expression level of LC3, thus increasing cell viability. Therefore, the present results suggested that excessive production of mROS induced by Ti ions led to autophagic cell death of osteoblasts, which is dependent on the SIRT3/SOD2 pathway.
种植体周围骨丧失的发生率很高，是一种难以治疗的疾病。先前的研究表明，植入物释放的钛 (Ti) 离子可导致成骨细胞损伤，但具体机制尚未阐明。本研究建立了 Ti 离子损伤成骨细胞模型。在该模型中检测了线粒体来源的活性氧（mROS）和自噬、细胞活力以及沉默调节蛋白 3（SIRT3）/超氧化物歧化酶 2（SOD2）途径的水平。结果发现 Ti 离子降低了成骨细胞的活力。此外，随着 Ti 离子浓度的增加，微管相关蛋白 1 轻链 3α（LC3）的表达水平逐渐增加，P62 减少，自噬流增加，mROS 水平增加。加入自噬抑制剂巴弗洛霉素 A1 和线粒体抗氧化剂 Mito-TEMPO 后，抑制 mROS 的产生，降低自噬水平，提高细胞活性。此外，随着 Ti 离子浓度的增加，SOD2 的活性降低，SOD2 的乙酰化水平增加，SIRT3 mRNA 和蛋白表达水平降低，SIRT3 的活性显著降低。此外，研究表明 SIRT3 过表达可降低 SOD2 的乙酰化水平并增加 SOD2 的活性，从而减少 mROS 的产生和 LC3 的表达水平，从而提高细胞活力。因此，本研究结果表明，Ti 离子引起的 mROS 过度产生导致成骨细胞自噬性细胞死亡，这依赖于 SIRT3/SOD2 途径。
