CatWalk XT Enables Sensitive Detection of Locomotor Deficits after C2 Hemisection and Integrates Readily into Ongoing...

Over half of all spinal cord injuries (SCIs) in the United States occur at the cervical level and often cause both life-threatening breathing dysfunction and profound locomotor deficits. Although the C2 hemisection (C2Hx) model is vital for study of breathing dysfunction after experimental SCI, post-C2Hx locomotor deficits have only been assessed by metrics such as the Martínez Scale and ladder tests, which require time-intensive scoring by human observers. However, the CatWalk XT Gait Analysis system (Noldus Information Technology) delivers automated, quantitative assessment of interlimb coordination, gait cycle, and paw function, providing robust locomotor data in a time-efficient and practical manner. CatWalk's efficiency may render it more feasible to incorporate locomotor analysis into studies that would not otherwise include such data, but it has not yet been applied to C2Hx. Thus, we conducted a proof-of-principle analysis using C2Hx-injured, adult female rats and uninjured naïve controls from two separate ongoing experiments. We hypothesized that C2Hx would produce primarily left-sided impairments measurable by CatWalk as predicted both by prior literature and the neuroanatomical specifics of the injury model. Indeed, CatWalk reliably identified pronounced deficits in left forepaw use and weight bearing, as well as impairments in stepping efficiency, interlimb coordination, speed, and overall gait stability across the 4-week period following injury. In summary, our findings demonstrate that CatWalk sensitively detects locomotor dysfunction after C2Hx and can be readily integrated into ongoing studies, thereby enhancing experimental efficiency and maximizing the scientific yield from existing animal cohorts.