Overview
- Researchers exposed 24 mice on the International Space Station to microgravity, 0.33 g, 0.67 g, and 1 g for up to 28 days using JAXA’s MARS centrifuge.
- The study, published in Science Advances, reports that 0.67 g preserved grip strength and muscle function at levels comparable to Earth gravity.
- At 0.33 g the mice maintained muscle size yet showed reduced strength and shifts in fiber composition, indicating function can decline before overt atrophy.
- Analyses of the gravity-sensitive soleus muscle identified 11 metabolites that varied with gravity, pointing to metabolic pathways linked to deconditioning.
- Experts caution that mouse results may not directly translate to humans and call for longer studies, assessments of bones and other tissues, and testing of exercise or artificial-gravity countermeasures.