RESUMO
BACKGROUND: The 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. METHODS: A 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. RESULTS: We 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). CONCLUSION: The combination of mechanical strain and icariin stimulation could activate the NF-κB pathway to improve the proliferation, differentiation of osteoblast-like cells.
Assuntos
Flavonoides/farmacologia , NF-kappa B/metabolismo , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Estresse Mecânico , Células 3T3 , Fosfatase Alcalina/metabolismo , Animais , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 4/metabolismo , Remodelação Óssea/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Osteoblastos/metabolismo , Osteocalcina/genética , Osteocalcina/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Objective. To establish the models of head, abdomen, and chest of supine human body respectively under vertical vibration. Method. The mechanical impedance of 12 healthy volunteers aged 24-56 was measured under vertical white noise stimulus in the frequency range of 2-35 Hz. To explain these findings, the model of head was proposed, the models of abdomen and chest were computed by way of an optimization procedure. Result. The models of abdomen and chest are three-degree-of-freedom and the head is rigid. Conclusion. The mechanical impedance of the supine human body is linear and sole. The established models of head, abdomen and chest of supine human body when subjected to vertical vibration are useful for calculating and evaluating the comfort of supine human body under whole-body vibration.