Mousny, Maryline
[UCL]
(eng)
Nowadays it is increasingly accepted that interactions with environmental factors must play an important role in determining bone quality and that these interactions must be influenced by genetics. Nevertheless, to date, only few animal studies explore an underlying genetic basis for extrinsic factors effect such as fluoride (F-) effect on bone metabolism.
This study assessed the effect of increasing F- doses on the bone properties in three inbred mouse strains that demonstrate different susceptibilities to developing enamel fluorosis (A/J a “susceptible” strain, 129P3/J a “resistant” strain and SWR/J an “intermediate” strain). Fluoride concentrations were determined in femora and vertebral bodies. Bone mineral density was evaluating through DXA (Dual energy X-ray Absorptiometry). Three-point bend testing of femora, compression testing of vertebral bodies and femoral neck-fracture testing were performed to evaluate mechanical properties. Bone microarchitecture was quantified with microcomputed tomography and strut analysis. Bone formation was evaluated by static histomorphometry. Bone mineralization was quantified with backscattered electron (BSE) imaging and powder x-ray diffraction. Microhardness measurements were taken from the vertebral bodies (cortical and trabecular bone) and the cortex of the distal femur.
Increasing doses of F- had different effects on the bone properties in the three inbred mouse strains. Although significant increases of bone F- concentration could be demonstrated, and no significant effects on bone macroarchitecture and BMD were found in the three strains, mechanical testing showed significant degradation of bone mechanical properties in the “susceptible” A/J strain, whereas moderate degradation in the “intermediate” SWR/J strain and no effect in the “resistant” 129P3/J strain were observed. Evaluation of the structural and material properties of the bone in the three strains showed that this different effect of F- on bone mechanical properties could be explained by an alteration of the mineral-organic interfacial bonding and/or bone matrix proteins, interfering with bone crystal growth inhibition on the crystallite faces as well as bonding between the mineral and organic interface. The smaller bone crystallites of the 129P3/J (resistant) strain may indicate a stronger organic-inorganic interface, reducing crystallite growth rate and increasing interfacial mechanical strength.
Bibliographic reference |
Mousny, Maryline. Genetics determine bone susceptibility to fluoride. Prom. : Banse, Xavier ; Devogelaer, Jean-Pierre |
Permanent URL |
http://hdl.handle.net/2078.1/28700 |