title: Different magnitudes of tensile strain induce human osteoblasts differentiation associated with the activation of ERK1/2 phosphorylation.
abstract: Mechanical factors are related to periprosthetic osseointegration following total hip arthroplasty. However, osteoblast response to strain in implanted femurs is unclear because of the absence of accurate stress-measuring methods. In our study, finite element analysis was performed to calculate strain distribution in implanted femurs. 0.8-3.2% tensile strain was then applied to human osteoblasts. Higher magnitudes of strain enhanced the expression of osteocalcin, type I collagen, and Cbfa1/Runx2. Lower magnitudes significantly increased ALP activity. Among these, type I collagen expression increased with the activation of ERK1/2 phosphorylation in a strain-magnitude-dependent manner. Our study marks the first investigation of osteoblast response at different magnitudes of periprosthetic strain. The results indicate that the functional status of human osteoblasts is determined by strain magnitude. The strain distribution in the proximal region of implanted femur should be improved for osseointegration.
authors.affiliation: Department of Orthopaedics, Shanghai the 6th People's Hospital, Jiaotong University, Shanghai, 200233, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Health Science, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200025, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai, 200030, China.
authors.forename: Chengtao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Shanghai the 6th People's Hospital, Jiaotong University, Shanghai, 200233, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Peng
authors.affiliation: Department of Orthopaedics, Shanghai the 6th People's Hospital, Jiaotong University, Shanghai, 200233, China.
authors.forename: Xianlong
authors.initials: X
authors.lastname: Zhang