Highlights
- •Whole bone femoral bending behaviors of skeletally mature rats was investigated.
- •Marked differences were found between young adult and late-middle-aged rats.
- •Findings suggest adult rat femurs modify continuously with age.
Abstract
Background
Skeletally mature rodents are frequently used in studies of bone health and bone healing,
some of them requiring longitudinal observations that span a significant portion of
the animals' adulthood. However, changes in whole bone mechanics associated with the
natural aging of adult rats have not been extensively characterized.
Methods
Femurs from skeletally mature Wistar rats in three age groups of 24-week (young adult),
39-week (middle-age), and 54-week (late middle-age) were tested under three-point
bending load in the anterior-posterior direction. Mechanical properties and geometric
properties of the femurs from the two older groups were compared to the 24-week rats.
Findings
Significantly greater strength, rigidity, and post-yield deformation were found in
the 54-week group when compared to the 24-week group. The oldest group also demonstrated
greater leg length, anteroposterior width, and cross-sectional moment of inertia over
the youngest group. Of the intrinsic properties, the highest ultimate stress was found
in the 39-week and was significantly higher than the 24-week group. The ultimate strain
increased with age, and the difference between the youngest and the oldest group was
statistically significant.
Interpretation
The results suggest that femoral bending properties and geometric properties are continually
modified from young adult to late-middle-aged animals. Knowing the baseline bone strength
and rigidity throughout adulthood of a rodent breed helps guide animal selection in
study design.
Keywords
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Article info
Publication history
Published online: November 24, 2022
Accepted:
November 22,
2022
Received:
February 12,
2022
Identification
Copyright
© 2022 Elsevier Ltd. All rights reserved.
