Gas7-Deficient Mouse Reveals Roles in Motor Function and Muscle Fiber Composition during Aging
Figure 4
Motor activity defects in old Gas7-deficient mice.
Wild-type (WT) and Gas7-deficient (MT) mice were classified into adult (3 to 6 months) and old (12 to 15 months) groups. (A) Rotarod test of wild-type and Gas7-deficient mice. The latency time indicates how long mice were able to walk on an accelerating rotarod at speeds from 5 to 40 rpm. No significant difference between adult wild-type and Gas7-deficient mice was observed (n = 22 each). In contrast, the time before falling decreased significantly for old Gas7-deficient mice compared to old wild-type mice (n = 15 each). Data points are mean ± SEM, ***P<0.001. (B) Adult Gas7-deficient mice performed no differently in regards to latency time than wild-type mice in four independent rotarod tests performed at constant speed (n = 22) (left panel). By contrast, old Gas7-deficient mice were significantly less able than old wild-type mice to stay on the rod, especially at lower rotation speeds with higher latency (mean ± SEM, n = 15, ** P<0.01) (right panel). (C) There was no difference between wild-type and Gas7-deficient mice in both adult (n = 22) and old (n = 15) groups in either stride length or width. Effects on gait were examined by analysis of footprints made with waterproof black ink on white paper. Mice with ink applied to the hind paws were induced to walk through a dark tube (43 cm × 7 cm × 10 cm). The step length (left-to-left and right-to-right distance) and width (left-to-right distance) were measured from their footprints. (D) Hanging tests to measure muscle strength. In the old group, the hanging ability decreased significantly in the Gas7-deficient mice compared to the wild-type (n = 15 each); however, adult mice showed no difference between groups (n = 22 in each group). Mean ± SEM, **P<0.01, *P<0.05.