Musculoskeletal Response to a Partial-gravity Analog in Rats: Structural, Functional, and Molecular Alterations (NNX16AL36G)
Health of the musculoskeletal system depends on exposure to mechanical loading. Removal or reduction of mechanical loading precipitates muscle atrophy and bone loss. Thus, despite rigorous exercise protocols and other countermeasures, muscle atrophy and bone loss are still virtually inevitable consequences of spaceflight. One approach for ameliorating the development of these untoward consequences of space travel is by the induction of artificial gravity during spaceflight via centrifugation. The strength of the artificial gravity depends both on the speed of rotation and diameter of the ship. While it is possible to achieve centrifugal force equivalent 1.0 G, it is also possible that lower levels of force may also be effective for preventing muscle atrophy and irreversible bone loss. In this study, we propose to evaluate the potential effectiveness of artificial gravity for the prevention of muscle atrophy and weakness and bone loss by studying rats using an innovative system for partial unloading that has been developed previously for mice by members of our team.
This work will also allow us to more effectively understand the relationship between the development of muscle atrophy and weakness and bone deterioration at varying levels of artificial gravity. At the conclusion of this study, we will have defined the potential impact of partial artificial gravity for prevention of musculoskeletal dysfunction and deterioration. This work will inform the future application of artificial gravity in human research and space exploration.
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We will study the musculoskeletal response of adult male rats (n=14 / group) following exposure to different degrees of unloading representing 0.2 G, 0.4 G, and 0.7 G as well as fully loaded animals for 1, 2, and 4 weeks. We will study the impact of this partial gravity analog environment on muscle and bone structure and function, including performing histological analyses, in situ force measurement of muscle contraction, as well as measurement of bone mass, microarchitecture, and strength. In addition, we will perform both serological and tissue molecular analyses to better understand the mechanisms and time course of development of these changes at different degrees of unloading.
This experiment is currently in progress. Results will be available at the conclusion of this study.
Mortreux M, Nagy JA, Ko FC, Bouxsein ML, Rutkove SB. A novel partial gravity ground-based analogue for rats via quadrupedal unloading.
J Appl Physiol (1985). 2018 Mar 22. [DOI]
Ko FC, Li J, Brooks DJ, Rutkove SB, Bouxsein ML. Structural and functional properties of bone are compromised in amyotrophic lateral sclerosis mice. Amyotroph Lateral Scler Frontotemporal Degener. 2018 Mar 23. [DOI]
Gastrocnemius muscle weight
Gastrocnemius-Electrical impedance measurements
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Soleus muscle - rodent
Soleus Tetanic Force
Soleus-Electrical impedance measurements
Weight, tissue, Soleus, muscle, rat