Lactoferrin promotes osteogenesis of MC3T3-E1 cells induced by mechanical strain in an extracellular signal–regulated kinase 1/2–dependent manner

Abstract

This study aimed to investigate the role of lactoferrin (LF) in the mechanical strain-induced osteogenesis of nontransformed osteoblastic cells (MC3T3-E1 cells) and related mechanism. MC3T3-E1 cells were cultured invitro and treated with 100μg/mL LF, followed by a 2000 μ mechanical strain load. U0126 was used to determine the role of extracellular signal-regulated kinase 1/2 (Erk1/2). Alizarin red S staining was performed to observe the cell mineralization potential. The osteogenic results were analyzed by reverse transcription-polymerase chain reaction and western blotting. The expression of Col1, Alp, Ocn, Bsp, and Opn mRNA and p-Erk1/2 proteins was significantly upregulated under mechanical strain load. In addition, mineralized nodule formation was increased. After adding LF, the expression of the biomarkers and the formation of mineralized nodules were further promoted. On treatment with the Erk1/2 inhibitor U0126, the expression of Col1, Alp, and p-Erk1/2 mRNA and protein was significantly downregulated. These findings demonstrate that LF promotes osteogenic activity by activating osteogenesis-related biomarkers, corroborating that the effects of mechanical strain depend on Erk1/2 signaling pathway.