title: The bio-response of osteocytes and its regulation on osteoblasts under vibration.
abstract: Vibration, especially at low magnitude and high frequency (LMHF), was demonstrated to be anabolic for bone, but how the LMHF vibration signal is perceived by osteocytes is not fully studied. On the other hand, the mechanotransduction of osteocytes under shear stress has been scientists' primary focus for years. Due to the small strain caused by low-magnitude vibration, whether the previous explanation for shear stress will still work for LMHF vibration is unknown. In this study, a finite element method (FEM) model based on the real geometrical shape of an osteocyte was built to compare the mechanical behaviors of osteocytes under LMHF vibration and shear stress. The bio-response of osteocytes to vibration under different frequencies, including the secretion of soluble factors and the concentration of intracellular calcium, were studied. The regulating effect of the conditioned medium (CM) from vibrated osteocytes on osteoblasts was also studied. The FEM analysis result showed the cell membrane deformation under LMHF vibration was very small (with a peak value of 1.09%) as compared to the deformation caused by shear stress (with a peak value of 6.65%). The F-actin stress fibers of osteocytes were reorganized, especially on the nucleus periphery after LMHF vibration. The vibration at 30 Hz has a promoting effect on osteocytes and the osteogenesis of osteoblasts, whereas vibration at 90 Hz was suppressive. These results lead to a conclusion that the bio-response of osteocytes to LMHF vibration is frequency-dependent and is more related to the cytoskeleton on nuclear periphery rather than the membrane deformation.
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 37th Xueyuan Road, Hian-dian District, Beijing, China.
authors.forename: Xin-Tong
authors.initials: XT
authors.lastname: Wu
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 37th Xueyuan Road, Hian-dian District, Beijing, China.|International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beijing, China.
authors.forename: Lian-Wen
authors.initials: LW
authors.lastname: Sun
authors.affiliation: School of Energy and Power Engineering, Beihang University, 37th Xueyuan Road, Hian-dian District, Beijing, China.
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Qi
authors.affiliation: School of Energy and Power Engineering, Beihang University, 37th Xueyuan Road, Hian-dian District, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Shi
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 37th Xueyuan Road, Hian-dian District, Beijing, China.|National Research Center for Rehabilitation Technical Aids, 1st Ronghuazhong Road, Beijing Economic and Technological Development Zone, Beijing, China.
authors.forename: Yu-Bo
authors.initials: YB
authors.lastname: Fan
mesh_terms: D000199:Actins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D003599:Cytoskeleton / Q000187:drug effects; D015232:Dinoprostone / Q000378:metabolism; D006801:Humans; D040542:Mechanotransduction, Cellular; D018613:Microscopy, Confocal; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D010011:Osteocytes / Q000166:cytology / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects; D033081:Shear Strength; D014732:Vibration
chemical_list: D000199:Actins; D017077:Culture Media, Conditioned; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D051546:Cyclooxygenase 2; D015232:Dinoprostone; D002118:Calcium
keywords: F-actin; FEM; MLO-Y4; osteoblasts; vibration