title: Interrelation between external oscillatory muscle coupling amplitude and in vivo intramedullary pressure related bone adaptation.
abstract: Interstitial bone fluid flow (IBFF) is suggested as a communication medium that bridges external physical signals and internal cellular activities in the bone, which thus regulates bone remodeling. Intramedullary pressure (ImP) is one main regulatory factor of IBFF and bone adaptation related mechanotransduction. Our group has recently observed that dynamic hydraulic stimulation (DHS), as an external oscillatory muscle coupling, was able to induce local ImP with minimal bone strain as well as to mitigate disuse bone loss. The current study aimed to evaluate the dose dependent relationship between DHS's amplitude, i.e., 15 and 30mmHg, and in vivo ImP induction, as well as this correlation on bone's phenotypic change. Simultaneous measurements of ImP and DHS cuff pressures were obtained from rats under DHS with various magnitudes and a constant frequency of 2Hz. ImP inductions and cuff pressures upon DHS loading showed a positively proportional response over the amplitude sweep. The relationship between ImP and DHS cuff pressure was evaluated and shown to be proportional, in which ImP was raised with increases of DHS cuff pressure amplitudes (R(2)=0.98). A 4-week in vivo experiment using a rat hindlimb suspension model demonstrated that the mitigation effect of DHS on disuse trabecular bone was highly dose dependent and related to DHS's amplitude, where a higher ImP led to a higher bone volume. This study suggested that sufficient physiological DHS is needed to generate ImP. Oscillatory DHS, potentially induces local fluid flow, has shown dose dependence in attenuation of disuse osteopenia.
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
authors.forename: Minyi
authors.initials: M
authors.lastname: Hu
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
authors.forename: Jiqi
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
authors.forename: Neville
authors.initials: N
authors.lastname: Bethel
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
authors.forename: Frederick
authors.initials: F
authors.lastname: Serra-Hsu
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Ferreri
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
authors.forename: Liangjun
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA. Electronic address: Yi-Xian.Qin@stonybrook.edu.
authors.forename: Yi-Xian
authors.initials: YX
authors.lastname: Qin
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D009132:Muscles / Q000502:physiology*; D009929:Organ Size; D011312:Pressure; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography
keywords: Bone fluid flow; Bone remodeling; Hydraulic fluid stimulation; Intramedullary pressure; Loading magnitude; Mechanical loading