Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
Curr Med Sci. 2019 Feb;39(1):75-80. doi: 10.1007/s11596-019-2002-x. Epub 2019 Mar 13.
Nowadays, the cumulative intake of glucocorticoids has become the most common pathogenic factor for non-traumatic osteonecrosis of the femoral head (ONFH). Apoptosis of osteoblasts is considered as the main reason of ONFH at the molecular level. Glycogen synthase kinase 3β (GSK3β) is an important regulator of cellular differentiation and apoptosis pathway, which can modulate the balance between osteoblasts and osteoclasts. Several studies have reported about its function in osteoporosis, but little is known about it in osteonecrosis. In our study, lipopolysaccharide and methylprednisolone were utilized to establish a rat ONFH model. The phosphorylation of GSK3β Ser-9 was decreased in the model. Western blotting examination of β-catenin, Bcl-2, Bax and caspase-3 revealed that the osteoblasts were apoptotic. In dexamethasone (Dex)-incubated primary osteoblasts, the expression profile of GSK3β phosphorylation and apoptotic factors were consistent with those in the rat ONFH model. To further investigate the regulation of osteonecrosis caused by GSK3β, the expression and function of GSK3β were inhibited in Dex-incubated primary osteoblasts. The knockdown of GSK3β by siRNA decreased the expression of Bax and cleaved caspase-3, but increased Bcl-2 and β-catenin. On the other hand, selective inhibition of GSK3β function by LiCl counteracted the activation of caspase-3 induced by Dex. Our work is the first study about the GSK3β phosphorylation in ONFH, and provides evidence for further therapeutic methods.
如今，糖皮质激素的累积摄入已成为导致非创伤性股骨头坏死（ONFH）的最常见致病因素。成骨细胞凋亡被认为是分子水平上 ONFH 的主要原因。糖原合酶激酶 3β（GSK3β）是细胞分化和凋亡途径的重要调节剂，可调节成骨细胞和破骨细胞之间的平衡。几项研究报道了其在骨质疏松症中的功能，但在骨坏死中知之甚少。在我们的研究中，利用脂多糖和甲基强的松龙建立了大鼠 ONFH 模型。模型中成骨细胞中 GSK3β Ser-9 的磷酸化减少。Western blot 检测β-catenin、Bcl-2、Bax 和 caspase-3 显示成骨细胞发生凋亡。在地塞米松（Dex）孵育的原代成骨细胞中，GSK3β磷酸化和凋亡因子的表达谱与大鼠 ONFH 模型一致。为了进一步研究 GSK3β 引起的骨坏死的调节作用，抑制 Dex 孵育的原代成骨细胞中 GSK3β 的表达和功能。siRNA 下调 GSK3β 表达降低了 Bax 和 cleaved caspase-3 的表达，但增加了 Bcl-2 和β-catenin 的表达。另一方面，LiCl 选择性抑制 GSK3β 功能可拮抗 Dex 诱导的 caspase-3 激活。我们的工作是关于 ONFH 中 GSK3β 磷酸化的第一项研究，为进一步的治疗方法提供了证据。
