Abstract
BackgroundThe combination of drugs and exercise was the effective treatment in bone injure and rebuilding in clinic. As mechanical strain has potential in inducing the differentiation of osteoblasts in our previous study, the further research to investigate the combination of mechanical strain and icariin stimulation on inducing osteoblast proliferation, differentiation and the possible mechanism in MC3T3-E1 cell line.MethodsA whole cell enzyme-linked immunosorbent assay that detects the bromodeoxyuridine incorporation during DNA synthesis was applied to evaluate the proliferation. The mRNA expression of alkaline phosphatase (ALP), osteocalcin (OCN), type I collagen (Col I), bone morphogenetic protein-2 (BMP-2) and BMP-4 was detected by real-time reverse-transcription polymerase chain reaction. The activity of ALP was analyzed by ELISA and the protein expression of OCN, Col I and BMP-2 was assessed by western blot. Moreover, the activity of nuclear transcription factor kappa-B (NF-κB) signaling pathway was investigated with the expression of inhibitor of κB (IκB) α, phosphorylation of IκB-α (P-IκB-α), p65, P-p65 by western blot.ResultsWe observed that compared to single mechanical strain or icariin stimulation, the mRNA and protein expressions of ALP (P < 0.05 or P < 0.01), OCN (P < 0.01) and Col I (P < 0.05 or P < 0.01) were increased significantly by the combination of mechanical strain and icariin stimulation. Moreover, the combination of mechanical strain and icariin stimulation could up-regulate the expression of BMP-2 (P < 0.01) and BMP-4 compared to single mechanical strain or icariin stimulation. The combination of mechanical strain and icariin stimulation could activate NF-κB signaling pathway by increasing the expression of IκB α, P-IκB-α, p65, P-p65 (P < 0.01).ConclusionThe combination of mechanical strain and icariin stimulation could activate the NF-κB pathway to improve the proliferation, differentiation of osteoblast-like cells.
Highlights
The combination of drugs and exercise was the effective treatment in bone injure and rebuilding in clinic
The mRNA expression of alkaline phosphatase (ALP) was investigated after mechanical strain, icariin, combination of mechanical strain and icariin stimulation in MC3T3-E1 cells
To determine whether this inhibitor of κB (IκB)-α degradation was related to IκB-α phosphorylation, we examined the effect of the mechanical strain, icariin, combination of mechanical strain and icariin stimulation on phorylation of IκB-α (P-IκB-α) by western blot, and found that combination of mechanical strain and icariin stimulation could increase IκB-α phosphorylation significantly (P < 0.01) in comparison with mechanical strain or icariin alone
Summary
The combination of drugs and exercise was the effective treatment in bone injure and rebuilding in clinic. The regular load is important for maintaining the integrity of bone described by Wolff’s law on the relationship between bone morphology and mechanical load [1]. Bone remodeling is a complex biological process depending on genetic, hormonal, metabolic and mechanical environment [6]. Mechanical loading plays an important role in the regulation of bone remodeling, since suitable mechanical stimulation could maintain normal bone volume [7]. Mechanical stimulation could be transmitted through the extracellular matrix (ECM) to resident osteoblasts, osteocytes, periosteal cells and osteoclasts in bone [8]. Osteoblasts were important mechanical receptors that transformed mechanical stimulation into biochemical signals, and could secrete bone matrix to promote bone matrix mineralization [9]
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