The incidence and morbidity of diabetes osteoporosis (DOP) are increasing with each passing year. Patients with DOP have a higher risk of bone fracture and poor healing of bone defects, which make a poor quality of their life. Bone tissue engineering based on autologous adipose-derived stem cells (ASCs) transplantation develops as an effective technique to achieve tissue regeneration for patients with bone defects. With the purpose of promoting auto-ASCs transplantation, this research project explored the effect of metformin on the osteogenic differentiation of ASCs under a high-glucose culture environment. In this study, we found that 40 mM high glucose inhibited the physiological function of ASCs, including cell proliferation, migration, and osteogenic differentiation. Indicators of osteogenic differentiation were all downregulated by 40 mM high glucose, including alkaline phosphatase activity, runt-related transcription factor 2, and osteopontin gene expression, and Wnt signaling pathway. At the same time, the cell autophagy makers BECLIN1 and microtubule-associated protein 1 light chain 3 (LC3 I/II) were decreased. While 0.1 mM metformin upregulated the expression of BECLIN1 and LC3 I/II gene and inhibited the expression of mammalian target of rapamycin (mTOR) and GSK3β, it contributed to reverse the osteogenesis inhibition of ASCs caused by high glucose. When 3-methyladenine was used to block the activity of metformin, metformin could not exert its protective effect on ASCs. All the findings elaborated the regulatory mechanism of metformin in the high-glucose microenvironment to protect the osteogenic differentiation ability of ASCs. Metformin plays an active role in promoting the osteogenic differentiation of ASCs with DOP, and it may contribute to the application of ASCs transplantation for bone regeneration in DOP.

中文翻译：

---

二甲双胍通过激活自噬挽救大鼠脂肪源性干细胞在高糖环境中受损的成骨分化能力

糖尿病骨质疏松症（DOP）的发病率和发病率逐年增加。DOP患者骨折风险较高，骨缺损愈合不良，导致生活质量较差。基于自体脂肪干细胞（ASCs）移植的骨组织工程已发展成为一种有效的技术来实现骨缺损患者的组织再生。本研究项目以促进自体ASCs移植为目的，探讨二甲双胍在高糖培养环境下对ASCs成骨分化的影响。在这项研究中，我们发现 40 mM 高糖抑制了 ASCs 的生理功能，包括细胞增殖、迁移和成骨分化。成骨分化指标均被 40 mM 高糖下调，包括碱性磷酸酶活性、矮小相关转录因子 2、骨桥蛋白基因表达和 Wnt 信号通路。同时，细胞自噬标志物 BECLIN1 和微管相关蛋白 1 轻链 3 (LC3 I/II) 减少。虽然 0.1 mM 二甲双胍上调 BECLIN1 和 LC3 I/II 基因的表达，并抑制哺乳动物雷帕霉素靶蛋白 (mTOR) 和 GSK3β 的表达，但它有助于逆转高糖引起的 ASC 成骨抑制。当使用3-甲基腺嘌呤阻断二甲双胍的活性时，二甲双胍不能发挥其对ASCs的保护作用。所有研究结果阐述了二甲双胍在高糖微环境中保护ASCs成骨分化能力的调控机制。二甲双胍在促进 DOP 的 ASCs 成骨分化中发挥积极作用，可能有助于 ASCs 移植在 DOP 骨再生中的应用。