Saito Hideo, Kishimoto Koshi N, Mori Yu, Okuno Hiroshi, Tanaka Masahiko, Itoi Eiji
Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Japan.
Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Japan.
J Orthop Sci. 2017 Mar;22(2):345-350. doi: 10.1016/j.jos.2016.12.005. Epub 2016 Dec 23.
Several lines of evidence indicate that the active form of vitamin D has an anabolic effect on skeletal muscle. Eldecalcitol, an analogue of the active form of vitamin D, has the potential to increase bone density and decrease fracture risk. The objective of this study was to investigate the effect of eldecalcitol in C2C12 myogenic cells.
C2C12 cells were grown to confluency and the culture medium was replaced with low-glucose DMEM containing 2% horse serum. Eldecalcitol was added at a concentration of 1, 10 or 100 nM. Gene expression profiles of vitamin D receptor (VDR), MyoD, IGF-1, neonatal myosin heavy chain (MHC), and the fast MHC subtypes Ia, IIa, IIb and IId/x were analyzed by quantitative RT-PCR. Protein expression of MHC subtypes was evaluated by western blotting and immunostaining.
Eldecalcitol upregulated gene expression of VDR, MyoD and IGF-1. Incubation with eldecalcitol in the absence of serum followed by the addition of serum after 1 h was associated with greater increases in the expression of these genes compared with co-incubation with eldecalcitol and serum. Gene expression of MHC subtypes IIa, IIb and IId/x was significantly increased by eldecalcitol. Protein expression of fast MHC subtypes was significantly increased by eldecalcitol at 1 and 10 nM.
Similar to the active form of vitamin D, eldecalcitol had an anabolic effect on fast MHC subtypes. Taking into account its pharmacokinetic profile, eldecalcitol is expected to be beneficial for the maintenance and improvement of muscle function in elderly individuals.
多项证据表明，维生素D的活性形式对骨骼肌具有合成代谢作用。 eldecalcitol是维生素D活性形式的类似物，具有增加骨密度和降低骨折风险的潜力。本研究的目的是探讨 eldecalcitol对C2C12成肌细胞的影响。
将C2C12细胞培养至汇合状态，然后用含2%马血清的低糖DMEM培养基替换培养基。加入浓度为1、10或100 nM的 eldecalcitol。通过定量RT-PCR分析维生素D受体（VDR）、MyoD、IGF-1、新生儿肌球蛋白重链（MHC）以及快速MHC亚型Ia、IIa、IIb和IId/x的基因表达谱。通过蛋白质印迹和免疫染色评估MHC亚型的蛋白质表达。
eldecalcitol上调了VDR、MyoD和IGF-1的基因表达。与在无血清条件下用 eldecalcitol孵育1小时后再添加血清相比，与 eldecalcitol和血清共同孵育时，这些基因的表达增加幅度更大。 eldecalcitol显著增加了MHC亚型IIa、IIb和IId/x的基因表达。在1和10 nM浓度下， eldecalcitol显著增加了快速MHC亚型的蛋白质表达。
与维生素D的活性形式相似， eldecalcitol对快速MHC亚型具有合成代谢作用。考虑到其药代动力学特征，预计 eldecalcitol对老年人肌肉功能的维持和改善有益。
