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Hindlimb suspension in Wistar rats: Sex-based differences in muscle response
Marie Mortreux1, Megan E Rosa-Caldwell1, Ian D Stiehl1,2
1Department of Neurology, Harvard Medical School - Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
Physiological Reports
|October 6, 2021
Summary
Female rats show better muscle function maintenance than males during hindlimb suspension (HLS), a spaceflight analog. This sex difference in muscle deconditioning highlights the need for tailored countermeasures for astronauts.
Area of Science:
- Space Biology
- Physiology
- Muscle Biology
Background:
- Ground-based animal models are crucial for understanding microgravity effects.
- Hindlimb suspension (HLS) in rats is a standard model for simulating unloading and fluid shifts.
- Limited research exists on sex-based differences in muscle response to HLS.
Purpose of the Study:
- To investigate how sex influences muscle deconditioning during HLS.
- To compare functional and structural muscle changes between male and female rats under unloading.
Main Methods:
- 28 Wistar rats (14 males, 14 females) were subjected to 14 days of HLS or normal loading (NL).
- Grip strength, force production, muscle mass, and cross-sectional area (CSA) were analyzed.
- Histomorphometric analyses were performed to assess muscle structure.
Main Results:
- Females exhibited significantly less reduction in grip strength and maintained muscle function better than males during HLS.
- Sex differences in muscle mass loss and CSA correlated with functional decrements.
- Statistical analysis revealed significant interactions between sex, time, and loading conditions.
Conclusions:
- Female rats demonstrate greater resilience to disuse-induced muscle deconditioning compared to males.
- Findings underscore the importance of considering sex in space biology research.
- Tailored countermeasures for muscle atrophy may be necessary for male and female astronauts.
