title: Effects of cyclic pressure on bone marrow cell cultures.
abstract: The present in-vitro study used bone marrow cell cultures and investigated the effects of cyclic pressure on osteoclastic bone resorption. Compared to control (cells maintained under static conditions), the number of tartrate resistant acid phosphatase (TRAP)-positive, osteoclastic cells was significantly (p<0.05) lower when, immediately upon harvesting, bone marrow cells were exposed to cyclic pressure (10-40 kPa at 1.0 Hz). In contrast, once precursors in bone marrow cells differentiated into osteoclastic cells under static culture conditions for 7 days, subsequent exposure to the cyclic pressure of interest to the present study did not affect the number of osteoclastic cells. Most important, exposure of bone marrow cells to cyclic pressure for 1 h daily for 7 consecutive days resulted in significantly (p<0.05) lower osteoclastic bone resorption and in lowered mRNA expression for interleukin-1 (IL-1) and tumor necrosisfactor-a (TNF-a), cytokines that are known activators of osteoclast function. In addition to unique contributions to osteoclast physiology, the present study provided new evidence of a correlation between mechanical loading and bone homeostasis as well as insight into the molecular mechanisms of bone adaptation to mechanical loading, namely cytokine-mediated control of osteoclast functions.
authors.affiliation: Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA.
authors.forename: Jiro
authors.initials: J
authors.lastname: Nagatomi
authors.forename: Bernard P
authors.initials: BP
authors.lastname: Arulanandam
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Metzger
authors.forename: Alain
authors.initials: A
authors.lastname: Meunier
authors.forename: Rena
authors.initials: R
authors.lastname: Bizios
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology* / Q000648:ultrastructure; D001862:Bone Resorption; D002452:Cell Count; D002478:Cells, Cultured; D016207:Cytokines / Q000032:analysis / Q000235:genetics; D005269:Femur / Q000502:physiology / Q000648:ultrastructure; D005786:Gene Expression Regulation; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D010010:Osteoclasts / Q000502:physiology* / Q000648:ultrastructure; D011312:Pressure; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D016207:Cytokines; D007527:Isoenzymes; D012333:RNA, Messenger; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase