title: Response of osteoblasts to low fluid shear stress is time dependent.
abstract: The process of mechanotransduction of bone, the conversion of a mechanical stimulus into a biochemical response, is known to occur in osteoblasts in response to fluid shear stress. In order to understand the reaction of osteoblasts to various times of flow perfusion, osteoblasts were seeded on three-dimensional scaffolds, and cultured in the following conditions: continuous flow perfusion, intermittent flow perfusion, and static condition. We collected samples on day 4, 8 and 12 for analysis. Osteoblast proliferation was demonstrated by cell proliferation and scanning electron microscopy assay. Additionally, the expression of known markers of differentiation, including alkaline phosphatase and osteocalcin, were tested by qRT-PCR and alkaline phosphatase activity assay, and the deposition of calcium was used as an indicator of mineralization demonstrated by calcium content assay. The results supported that low fluid shear stress plays an important role in the activation of osteoblasts: enhance cell proliferation, increase calcium deposition, and promote the expression of osteoblastic markers. Furthermore, the continuous flow perfusion is a more favorable environment for the initiation of osteoblast activity compared with intermittent flow perfusion. Therefore, the force and time of fluid shear stress are important parameters for osteoblast activation.
authors.affiliation: Department of Implantology, West China College of Stomatology, Sichuan University, No. 14, Sec. 3, Renminnan Road, Chengdu 610041, Sichuan, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ban
authors.forename: Ying-ying
authors.initials: YY
authors.lastname: Wu
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.forename: Ning
authors.initials: N
authors.lastname: Geng
authors.forename: Yong-yue
authors.initials: YY
authors.lastname: Wang
authors.forename: Xiao-guang
authors.initials: XG
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Gong
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015415:Biomarkers; D002113:Calcification, Physiologic; D002118:Calcium / Q000378:metabolism; D002452:Cell Count; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D002470:Cell Survival; D005109:Extracellular Matrix / Q000378:metabolism; D005786:Gene Expression Regulation; D040542:Mechanotransduction, Cellular; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D015675:Osteocalcin / Q000378:metabolism; D016062:Porosity; D011673:Pulsatile Flow; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013997:Time Factors; D054457:Tissue Scaffolds
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D002118:Calcium