Comprehensive Understanding of Inactivity-induced Gait Alteration in Rodents

It is well known that disuse affects neural systems and that joint motions become altered; however, which outcomes properly exhibit these characteristics is still unclear. The present study describes a motion analysis approach that utilizes three-dimensional (3D) reconstruction from video captures. Using this technology, disuse-evoked alterations of walking performances were observed in rodents exposed to a simulated microgravity environment by unloading their hindlimb by their tail. After 2 weeks of unloading, the rats walked on a treadmill, and their gait motions were captured with four charge-coupled device (CCD) cameras. 3D motion profiles were reconstructed and compared to those of control subjects using the image processing software. The reconstructed outcome measures successfully portrayed distinct aspects of distorted gait motion: hyperextension of the knee and ankle joints and higher position of the hip joints during the stance phase. Motion analysis is useful for several reasons. First, it enables quantitative behavioral evaluations instead of subjective observations (e.g., pass/fail in certain tasks). Second, multiple parameters can be extracted to fit specific needs once the fundamental datasets are obtained. Despite hurdles for broader application, the disadvantages of this method, including labor intensity and cost, may be alleviated by determining comprehensive measurements and experimental procedures.