Figure 2. Gait analysis (Footprint ink test).

a. Representative footprint comparison of Glb1 mice. Glb1^+/+ and Glb1^−/− mice were trained to travel a straight path to analyze their gait. Forepaws and hind paws were coated with green and black ink respectively, to evaluate placement of paws during walking. Glb1^+/+ mice show an alternate gait pattern in which right and left limbs move separately in both the forelimbs and hind limbs. In contrast, Glb1^−/− mice have abnormal foot placement in the footprint ink test. b. Representation of gait parameters (modified from Lubjuhn et al.[22]). Paw angle was defined as the angle that paw makes with the long axis of the direction of motion of the animal; step angle, the angle between left and right hind paws as a function of stride length and stance width; stride length, the spatial length that a paw traverses through a stride; stance width, the perpendicular distance between the center point of either set of axil paws during the peak stance. c. Female (n=9–10) and d. Male (n=9–11) front paw angle (degrees). e. Female (n=9–10) and f. Male (n=9–11) hind paw angle (degrees) in Glb1^−/− is greatly reduced and axis of the front and hindfeet are turned inward towards center axis, and the Glb1^−/− mice also show extra placement/steps of forepaws. The Glb1^−/− footprints also appear less well defined than the Glb1^+/+. g. Female (n=9–10) and h. Male (n=9–11) forelimb stride length distance (cm). i. Female (n=9–10) and j. Male (n=9–11) hindlimb stride length distance (cm) in Glb1^−/− mice are significantly shorter than Glb1^+/+ mice. k. Female (n=9–10) and l. Male (n=9–11) step angle (degrees). Data are presented as mean ± SD of 8-, 20- and 32-week old mice (two-tailed unpaired t-test with Welch’s correction).