Geometrical, Mechanical, and Structural Adaptation of Mouse Femora Exposed to Different Loadings
Publication: Journal of Engineering Mechanics
Volume 124, Issue 2
Abstract
Juvenile mice were utilized as a model system to study the influence of different activity regimens on the change in bone morphology and load-bearing capacity of their femora. Two treatment groups were employed: one exposed to 4g hypergravity (HG) and the other to chronic digging in high ground corn cob litter (HL). A voluntary normal exercise group (NE) served as control. One femur from each animal was used to determine the geometrical properties of the bone; the other femur was used in a load-to-failure experiment. Electron micrographs of femur cross sections were digitized to yield geometrical properties of the bone. Young's modulus and the stress and strain at failure for the bone were determined via a modified Euler beam model. Strain energy was evaluated directly from load-deflection curves obtained during the load-to-failure experiments. Average strain-energy density was then derived from these results. Cross-sectional geometrical properties (diameters, wall thicknesses, area, moments of inertia, and section modulus), mechanical properties (stress at failure and strain energy), and structural properties (bending stiffness, extensional stiffness, and moment at failure) were found to be statistically larger in HG and/or in HL when compared with NE (p< 0.05). Average strain-energy density and strain for HG were much larger than for NE or HL (p≤ 0.05) and Young's modulus had the trend reversed. The present study indicates that juvenile mouse femora grow, model, and fail in a manner unique to the activity regimen under which they are raised.
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References
1.
Amtmann, E., and Oyama, J.(1973). “Changes in functional construction of bone in rats under conditions of simulated increased gravity.”Zeitschrift fur Anatomie und Entwicklungsgeschichte, 139(2), 307–318.
2.
C-Rodriguez, E., and Gordon, K. R. (1990). “Effects of psychological stress on growth and strength of mouse femora.”Am. Zoologist, 130(1), 76A.
3.
Currey, J. (1984). The mechanical adaptation of bone. Princeton University Press, Princeton, N.J.
4.
den Hartog, J. P. (1952). Advanced strength of materials. McGraw-Hill, Inc., New York, N.Y.
5.
Ding, J.-H., Sheckter, C.-B., Drinkwater, B. L., Soules, M. R., and Bremner, W. J.(1988). “High serum cortisol levels in exercise-associated amenorrhea.”Ann. of Internal Medicine, 108(3), 530–534.
6.
Ferretti, J. L., Vazquez, S. O., Delgado, C. J., Capozza, R., and Cointry, G.(1992). “Biphasic dose-response curves of cortisol effects on rat diaphyseal bone biomechanics.”Calcified Tissue Int., 50(1), 49–54.
7.
Goodship, A. E., Lanyon, L. E., and McFie, H. (1979). “Functional adaptation of bone to increased stress.”J. Bone and Joint Surgery, 61A(3), 539–546.
8.
Gordon, K. R. (1985). “The correlation of experimentally applied loads with the architecture of cancellous bone in the femur of developing mice.”Am. Zoologist, 25(4), 22A.
9.
Gordon, K. R., Levy, C., Perl, M., and Weeks, O. I. (1993). “Adaptive modeling in a mammalian skeletal model system.”Growth, Devel. and Aging, 57(Summer), 101–110.
10.
Gordon, K. R., Reese, S. R., and Knecht, P. A.(1989). “Changes in the architecture of cancellous bone in the femora of developing mice as a result of short duration hypergravity.”Am. Zoologist, 29(2), 205–219.
11.
Grimston, S. K., Willows, N. D., and Hanley, D. A.(1993). “Mechanical loading regime and its relationship to bone mineral density in children.”Medicine and Sci. in Sports and Exercise, 25(11), 1203–1210.
12.
Jones, H. H., Priest, J. D., Hayes, W. C., Tichenor, C. C., and Nagel, D. A. (1977). “Humeral hypertrophy in response to exercise.”J. Bone and Joint Surgery, 59A(2), 204–208.
13.
Lanyon, L. E.(1984). “Functional strain as a determinant for bone remodeling.”Calcified Tissue Int., 36(3), 556–561.
14.
Lanyon, L. E., Rubin, C. T., and Banst, G.(1986). “Modulation of bone loss during calcium insufficiency by controlled dynamic loading.”Calcified Tissue Int., 38(1), 209–216.
15.
Martens, M., van Audekercke, R., de Meester, P., and Mulier, J. C.(1986). “Mechanical behaviour of femoral bones in bending loading.”J. of Biomech., 19(4), 443–454.
16.
Meade, J. B., Cowin, S. C., Klawitter, J. J., Van Buskirk, W. C., and Skinner, H. B. (1984). “Bone remodeling due to continuously applied loads.”Calcified Tissue Int., 36, S25–S30.
17.
Rubin, C. T., and Lanyon, L. E.(1985). “Regulation of bone mass by mechanical strain magnitude.”Calcified Tissue Int., 37(3), 411–417.
18.
Smith, S. D.(1977). “Femoral development in chronically centrifuged rats.”Aviation Space and Envir. Medicine, 48(9), 828–835.
19.
Timoshenko, S. P. (1956). Strength of materials, Part 1 (Chapter 6), and Part 2 (Chapter 2), Van Nostrand Publishing, Princeton, N.J.
20.
Timoshenko, S. P., and Goodier, J. N. (1970). Theory of elasticity, 3rd Ed., McGraw-Hill, Inc., New York, N.Y.
21.
Woo, S. L.-Y., et al. (1981). “The effect of prolonged physical training on the properties of long bone. A study of Wolff's law.”J. Bone and Joint Surgery, 63A(5), 780–787.
22.
Wunder, C. C.(1977). “Femur-bending properties as influenced by gravity: III. Sex-related weakness after 4-g mouse growth.”Aviation Space and Envir. Medicine, 48(10), 1023–1025.
23.
Wunder, C. C., and Welch, R. C.(1977). “Femur-bending properties as influenced by gravity: II. Ultimate load, moment and stress for 3-g mice.”Aviation Space and Envir. Medicine, 48(8), 734–736.
24.
Yoon, H. S., and Katz, J. L.(1976). “Ultrasonic wave propagation in human cortical bone. I. Theoretical considerations for hexagonal symmetry.”J. Biomech., 9(5), 407–412.
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Copyright © 1998 American Society of Civil Engineers.
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Published online: Feb 1, 1998
Published in print: Feb 1998
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