Abstract/Details

Functional adaptation of bone

LaMothe, Jeremy Michael. 
 University of Calgary (Canada) ProQuest Dissertations Publishing,  2004. NQ97878.

Abstract (summary)

Mechanical stimuli can be a vital determinant of bone morphology. How bones perceive and respond to those stimuli remains equivocal, but intracortical bone fluid flow has been suggested to influence bone cell activities. The current studies were designed to determine indirectly relations between intracortical fluid flow and adaptive osteogenesis. A cantilever loading device was constructed to apply non-invasive loads to skeletally mature female C57BL/6 tibiae 5 d·wk −1 for 4 wk. Double calcein injections were administered to permit histomorphometrical indices of adaptation. Loading was conducted while under halothane anaesthesia. Halothane was found to be a good anaesthetic agent for chronic adaptation studies as it did not confound histomorphometrical indices of osteogenesis. Periosteal osteogenesis exhibited a dose-response relation with loading rate. Those adaptations were histomorphometrically and biomechanically relevant. When loading cycles were separated by brief rest periods (<1 s), osteogenesis was significantly enhanced. Similarly, longer rest periods (10 s) were effectively used in combination with short bouts of high-frequency loading regimes. The current studies also showed substantial periosteal responses and slight endosteal responses. Periosteal osteogenesis was significantly negatively correlated with endosteal osteogenesis; the spatial distribution of osteogenesis showed that medial-lateral tibial cantilever bending accelerated an age-related modeling drift. Spatially, endosteal osteogenesis was significantly correlated with circumferential strain gradients in only two of the loading groups. Thus, no single mechanical parameter could explain adaptive osteogenesis in all of the loading groups supporting the complexity of bone adaptation. The data from the current studies emphasized the sensitivity of the adult skeleton to specific physical parameters. Those parameters the skeleton was most sensitive to related to enhanced intracortical fluid flow velocities and volumes. Optimization of osteogenesis in response to mechanical loading may underpin the development of nonpharmacological regiments designed to increase bone mass.

Indexing (details)


Subject
Biomedical research
Classification
0541: Biomedical research
Identifier / keyword
Applied sciences; Bone; Functional adaptation
Title
Functional adaptation of bone
Author
LaMothe, Jeremy Michael
Number of pages
205
Degree date
2004
School code
0026
Source
DAI-B 65/12, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
978-0-612-97878-2
Advisor
Zernicke, R. F.
University/institution
University of Calgary (Canada)
University location
Canada
Degree
Ph.D.
Source type
Dissertation or Thesis
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
NQ97878
ProQuest document ID
305228685
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
https://www.proquest.com/docview/305228685