Changes in metabolism and vestibular function depend on gravitational load in mice

Area of Science:

• Physiology
• Gravitational Biology
• Neuroscience

Background:

• The vestibular system is crucial for posture and metabolism control.
• Gravitational changes (microgravity, hypergravity) induce vestibular system plasticity for adaptation.
• The relationship between gravitational loading magnitude and vestibular function changes is not well understood.

Purpose of the Study:

• To investigate if the degree of change in vestibular-related physiological functions is dependent on gravitational loading.
• To examine the effects of sustained hypergravity on posture control, metabolism, and body mass in mice.

Main Methods:

• Mice were exposed to hypergravity environments of 1.33 G, 1.67 G, and 2 G for 29 days.
• Physiological parameters including body mass, food and water intake, body temperature, and righting reflex were monitored.

Main Results:

• Hypergravity induced physiological changes, including altered posture control and metabolism, with effects dependent on gravitational load.
• Body mass did not recover to pre-load levels in 1.67 G and 2 G groups.
• A 2 G load significantly affected water intake, body temperature, and righting reflex, indicating substantial vestibular-related functional changes.

Conclusions:

• Hypergravity-induced alterations in metabolism and vestibular function are dependent on the magnitude of gravitational loading.
• A 2 G gravitational load significantly impacts vestibular-related autonomic and motor functions more than 1.33 G or 1.67 G.
• These findings suggest that the vestibular system undergoes plastic alterations in response to varying gravitational loads.