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Characterizing the osteoporotic rat model using new techniques



DOI:10.1038/bonekey.2012.169

This study sought to further characterize the mature ovariectomized rat model of postmenopausal osteoporosis by measuring structural bone changes using microcomputed tomography and then correlating those findings with levels of serum biomarkers of bone turnover and femur mRNA expression profiles.

Scan results indicated that bone volume fraction declines by 30–50% as soon as four weeks after ovariectomy. The higher levels of osteocalcin and degradation fragments of collagen in the serum confirmed the development of a higher rate of bone turnover. Analysis of mRNA expression profiles of osteocalcin and type 1 collagen, both osteoblast marker genes, and cathepsin K and tartrate-resistant acid phosphatase 5, both osteoclast marker genes, showed that both osteoblasts and osteoclasts were activated during this process.

Although ovariectomized rats showed a significant decline in trabecular number and thickness in their vertebrae compared to sham controls, the sham animals did show some senescence-related changes in trabecular morphology.

Editor's comment: The changes of trabecular morphology reported in the sham animals as a consequence of ″senescence″ are interesting: it might suggest that rats aged 12 months (mature pluriparous animals) are too old even for sham intervention. The authors seem to exclude an explanation that this ″trabecular aging″ might be an artifact of multiple scans with ionizing radiation.


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