Summary
A longitudinal bone survey was conducted in 86 female Wistar rats in order to assess
mineral density kinetics from young age (5 weeks: 115 g) till late adulthood (64 weeks:
586 g). In vivo quantitative radiographic scanning was performed on the caudal vertebrae,
taking trabecular mass as the parameter. Measurements were expressed as Relative Optical
Density (ROD) units by means of a high resolution densitometric device. Results showed
a progressive increase in mineral density throughout the life cycle, with a tendency
to level in the higher weight range, indicating that progressive mineral aposition
occurs in rats in dependency of age. This phenomenon, however, should be always considered
within the context of continuous skeletal growth and related changes typical of this
species.
Twelve different animals were also examined following induction of articular inflammation
with Freund's adjuvant in six of them. Bone survey conducted 12 to 18 days after inoculation
revealed a significant (P < 0.01) reduction in trabecular bone mass of scanned vertebrae
in comparison with the weight-matched untreated controls.
It is concluded that the in vivo quantitative assessment of bone density illustrated
in this report represents a sensitive and useful tool for the long-term survey of
naturally occurring or experimentally induced bone changes. Scanning of the same part
of the skeleton can be repeated, thereby avoiding sacrifice of the animal and time-consuming
preparation of post-mortem material.
Key-Words
Bone Density
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Rats
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Life Cycle
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Arthritis
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Osteopenia
