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Strain dependent differences in gait dynamics
Ajit Kale*, Peter Mueller, Wade Thomas*, Jamie Bridges, Ruediger Volk,
Ivo Amende, and Thomas G. Hampton;
Mouse Specifics, Inc. and *The CuraVita Corporation, Boston, MA.
Web published: May 1, 2002
Abstract
Strains of mice with different genetic backgrounds may be useful for modeling different types of neuromuscular or skeletal muscle disease. The SOD1 mouse, for example, a model of amyotrophic lateral sclerosis (ALS), is on a C57B6SJL background. The mdx mouse, a model of Duchenne muscular dystrophy, has a C57BL/10ScSn (B10) background. BKS.Cg-m+/+Leprdb mice, have increased susceptibility to diabetes and therefore might be good animals for modeling diabetes-related neuropathies. Accordingly, establishing benchmark gait indices in normal control mice will accelerate the identification of phenotypes in potential mutants. Here, we demonstrate differences in gait dynamics in two strains of mice, B10 and C57BLKS/J (BKS).
Methods
Figure 1.Gait dynamics in a B10 mouse (red) and BKS (green).
Gait dynamics in 3 adult male B10 mice and 3 adult BKS mice (obtained from The Jackson Laboratory) were monitored using The CuraVitaTM Gait Imaging system. Neither restraint nor anesthetic was required. Recordings were performed with the treadmill speed set to cause the mice to walk at a speed of 24 cm/s. Only images corresponding to a minimum of 6 continuous strides were used in analyses. e-MOUSETM signal detection algorithms were used to interpret the gait signals.1 Gait indices were based on pooling recordings from the front and hind limbs.
Results
Gait indices in B10 and BKS mice.
B10 (99 strides)
BKS 76 strides)
Brake Time (ms)
96 ± 6
122 ± 9*
Propulsion Time (ms)
109 ± 7
147 ± 7*
Stance Time (ms)
205 ± 11
269 ± 14*
Swing Time (ms)
78 ± 16
56 ± 5
Stride Length (cm)
6.2 ± 0.1
8.1 ± 0.2*
Stride Freq (strides/sec)
3.7 ± 0.1
2.9 ± 0.1*
Mean ± SEM. *P<0.05.
Discussion
Gait dynamics were significantly different between the two mouse strains. Figure 1 illustrates stride dynamics for the right rear paws of a B10 mouse and a BKS mouse. Table 1 summarizes gait indices determined in the two strains. B10 mice maintained walking speed by faster stride frequency and shorter stride length. Stance time was significantly longer in BKS mice than in B10 mice. Propulsion consumed the greater portion of stance in both strains. The proportion of stride time spent in the swing phase was significantly longer in B10 mice. To the extent these differences reflect differences in muscle strength or joint mobility remains to be determined. As in dog2, braking duration was significantly greater in the forelimbs, whereas propulsion duration was generally longer in the hind limbs; this phenomena was more evident in the BKS strain, suggesting a greater load dependence on hind limbs in BKS mice, or perhaps a more even distribution of load in the front and rear paws in the B10 strain. Analyses of gait in mouse models of diabetes may demonstrate abnormalities associated with peripheral neuropathy3 or deterioration of glucose tolerance.4 Moreover, gait analyses in mouse models of ALS could help quantify the correlation between motor neuron degeneration and gait changes5 and demonstrate if drugs, such as cyclosporin and minocycline, which prolong survival of late-stage ALS mice6,7, may prevent or delay deterioration in locomotive capacity.
References
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Hitunen, L.A. 2001. Cent. Eur. J. Public Health 9:22-25.
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