title: In vivo dynamic loading reduces bone growth without histomorphometric changes of the growth plate.
abstract: This in vivo study aimed at investigating the effects of dynamic compression on the growth plate. Rats (28 days old) were divided into three dynamically loaded groups, compared with two groups (control, sham). A device was implanted on the 6th and 8th caudal vertebrae for 15 days. Controls (n = 4) did not undergo surgery. Shams (n = 4) were operated but not loaded. Dynamic groups had sinusoidal compression with a mean value of 0.2 MPa: 1.0 Hz and ± 0.06 MPa (group a, n = 4); 0.1 Hz and ± 0.2 MPa (group b, n = 4); 1.0 Hz and ± 0.14 MPa (group c, n = 3). Growth rates (µm/day) of dynamic groups (a) and (b) were lower than shams (p < 0.01). Growth plate heights, hypertrophic cell heights and proliferative cell counts per column did not change in dynamic (a) and (b) groups compared with shams (p > 0.01). Rats from dynamic group (c) had repeated inflammations damaging tissues; consequently, their analysis was unachievable. Increasing magnitude or frequency leads to growth reduction without histomorphometric changes. However, the combined augmentation of magnitude and frequency alter drastically growth plate integrity. Appropriate loading parameters could be leveraged for developing novel growth modulation implants to treat skeletal deformities.
authors.affiliation: Department of Mechanical Engineering, École Polytechnique of Montreal, P.O. Box 6079, Station "Centre-Ville,", Montréal, Québec, Canada, H3C 3A7; Sainte-Justine University Hospital Center, 3175 Côte-Ste-Catherine Rd., Montréal, Québec, Canada, H3T 1C5.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Ménard
authors.forename: Guy
authors.initials: G
authors.lastname: Grimard
authors.forename: Barthélémy
authors.initials: B
authors.lastname: Valteau
authors.forename: Irène
authors.initials: I
authors.lastname: Londono
authors.forename: Florina
authors.initials: F
authors.lastname: Moldovan
authors.forename: Isabelle
authors.initials: I
authors.lastname: Villemure
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D001846:Bone Development / Q000502:physiology*; D049109:Cell Proliferation; D019902:Chondrocytes / Q000473:pathology; D006132:Growth Plate / Q000473:pathology* / Q000503:physiopathology*; D006984:Hypertrophy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013623:Tail; D016474:Weight-Bearing / Q000502:physiology*
keywords: growth plate; histomorphometry; in vivo dynamic compression; mechanical modulation; rat caudal vertebra