Discordance in Recovery Between Altered Locomotion and Muscle Atrophy Induced by Simulated Microgravity in Rats

ABSTRACT

Exposure to a microgravity environment leads to adverse effects in motion and musculoskeletal properties. However, few studies have investigated the recovery of altered locomotion and muscle atrophy simultaneously. The authors investigated altered locomotion in rats submitted to simulated microgravity by hindlimb unloading for 2 weeks. Motion deficits were characterized by hyperextension of the knees and ankle joints and forward-shifted limb motion. Furthermore, these locomotor deficits did not revert to their original form after a 2-week recovery period, although muscle atrophy in the hindlimbs had recovered, implying discordance in recovery between altered locomotion and muscle atrophy, and that other factors such as neural drives might control behavioral adaptations to microgravity.

Keywords:

• hindlimb unloading
• rats
• locomotion
• kinematics
• sensorimotor adaptation

FUNDING

This study was supported in part by a JSPS KAKENHI Grant-in-Aid for Scientific Research (A) (no. 25242055) and a JSPS KAKENHI Grant-in-Aid for Challenging Exploratory Research (no. 25560258).

SUPPLEMENTAL DATA

Supplemental data for this article can be accessed at www.tandfonline.com/vjmb.