Catwalk

For gait analysis, the CatWalk (Noldus Information Technology) automated, computer‐assisted system was used, which is often used to assess locomotion defects in stroke mouse models.^[90] The CatWalk apparatus comprises a long, elevated glass runway platform that is fluorescently illuminated from the inside; the light is reflected in the direction of the floor when pressure (weight) is applied on top. A camera is mounted underneath the glass platform to record the walking pattern. At the beginning of the experiment, the animals’ home cage was placed at one end of the platform. Then, the mice were placed on the opposite end and allowed to walk across the platform voluntarily toward their home cage. Analysis was performed with CatWalk XT 10.5 Software, which visualizes the footprints and calculates statistics regarding their dimensions and the time and distance ratios between footfalls. For a trial to be considered successful, the speed should not vary by more than 60% and the run should be uninterrupted (i.e., the mouse should not stop on the runway). Unsuccessful trials were repeated until three successful trials were reached. Before baseline acquisition, mice were preoperatively trained for 3 days with the CatWalk system (3 runs per day). The test was then performed on day 10 after MCAO.

CatWalk (Noldus, Wageningen) analysis was used to investigate dynamic walking patterns. The core components of the system comprise an illuminated glass plate and a camera under the walkway. Rats were trained to cross the vitreous walkway, and each footprint was analyzed into pixels of digital brightness footprint ranging from 0 to 255 (arbitrary units). The analysis system CatWalk XT (version 10.6) was employed to quantify the data and generate digital parameters, including qualitative and quantitative assessments of individual footprints and gait parameters to evaluate the overall hind paw recovery, maximum contact area, regularity index, swing, and stride length. Prior to recording, all rats were placed on CatWalk glass plates for 20 min to avoid stress-related biases.

Gait assessment was performed at P31 using the CatWalk quantitative gait analysis system (Noldus Information Technology, Wageningen, The Netherlands) as previously described (13 (link)). The experimental rats ran across a glass walkway transversely, and the runs were recorded by a camera positioned below. If an animal failed to complete a run within 5 s, walked backward, or reared during the run, the process was repeated with each rat, and the average of three runs was calculated. The glass walkway was illuminated with beams of light in the dark atmosphere as the animals' paws could reflect light as they touched the glass floor. To calculate the paw-related parameters, each paw was labeled on the recorded video. In the experiment, the contact area (area of paw print) and maximal intensity (the maximal intensity of each paw in the run) were measured.