Locomotor Recovery in Spinal Cord Injury Can Be Assessed Using Weight-Bearing

Abstract

Spinal cord injury (SCI) can result in partial or full paralysis, depending on the level and completeness of injury. Locomotor function is often used as a measure of recovery and treatment outcomes. The Basso, Beattie, and Bresnahan scale and Basso Mouse Scale (BMS) are gold standards used in rodent SCI studies to evaluate changes in locomotor recovery. However, these scoring systems are observer-dependent measures that may be affected by the presence of an experimenter, particularly in studies where blinding is difficult. Observer-independent methods measure outcomes without an operator present, thus reducing bias and increasing reproducibility between research groups. Changes in locomotor recovery were evaluated after contusive SCI using the Advanced Dynamic Weight Bearing (ADWB) system, previously used successfully to assess acute and chronic pain. We observed a shift in body weight early after injury, with increased surface area and weight placement to the front paws and the trunk/tail region. Concurrently, there was a reduction in rear paw surface area and weight placement. As functional recovery occurred over time, there was a shift toward reduced weight placement on the front paws. As with locomotor recovery, these changes did not return to preinjury levels. We also found that the rate and degree to which mice shifted weight onto front paws depended on injury severity. Importantly, changes in weight distribution and surface area showed a strong correlation with BMS scores, suggesting that the observer-independent ADWB test is a viable measure to assess changes in locomotor function over time after SCI.