Gait performance of adolescent mice assessed by the CatWalk XT depends on age, strain and sex and correlates with speed and body weight

Abstract

The automatization of behavioral tests assessing motor activity in rodent models is important for providing robust and reproducible results and evaluating new therapeutics. The CatWalk system is an observer-independent, automated and computerized technique for the assessment of gait performance in rodents. This method has previously been used in adult rodent models of CNS-based movement disorders such as Parkinson's and Huntington's diseases. As motor and gait abnormalities in neuropsychiatric disorders are observed during infancy and adolescence, it became important to validate the CatWalk XT in the gait analysis of adolescent mice and unravel factors that may cause variations in gait performance. Three adolescent wild-type inbred mouse strains, C57BL/6N, DBA/2 and FVB/N, were tested using the CatWalk XT (Version 10.6) for suitable detection settings to characterize several gait parameters at P32 and P42. The same detection settings being suitable for C57BL/6N and DBA/2 mice allowed a direct comparison between the two strains. On the other hand, due to their increased body weight and size, FVB/N mice required different detection settings. The CatWalk XT reliably measured the temporal, spatial, and interlimb coordination parameters in the investigated strains during adolescence. Additionally, significant effects of sex, development, speed and body weight within each strain confirmed the sensitivity of motor and gait functions to these factors. The CatWalk gait analysis of rodents during adolescence, taking the effect of age, strain, sex, speed and body weight into consideration, will decrease intra-laboratory discrepancies and increase the face validity of rodent models of neuropsychiatric disorders.

Figure 1

(a) Graphical representation of selected gait parameters. RF right front paw, LF left front paw, RH right hind paw, LH left hind paw. (b) FVB/N mice showed increased body weight compared to C57BL/6N and DBA/2 mice at P32 and P42. (c) Comparison of the body weights of mice at P32 and P42 within each strain. Two-way ANOVA followed by Tukey’s post hoc test for multiple comparisons to determine differences between the three strains and Bonferroni correction to check differences between males and females within each strain, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM).

Figure 2

Comparison of run characteristics and kinetic, temporal and spatial parameters between C57BL/6N and DBA/2 mice at P32. (a) DBA/2 mice showed a significant increase in the average speed and cadence and a decreased number of steps compared to C57BL/6N mice. (b,c) DBA/2 mice showed an increase in body speed (b) and swing speed (c) in all paws compared to C57BL/6N mice (d–g) DBA/2 mice showed a significant decrease in stand time (d), swing time (e), step cycle (f) and maximum contact at (%) (g) of all paws compared to C57BL/6N mice. (h,i) DBA/2 mice showed an increase in print area (h) and maximum intensity (i) of all paws compared to C57BL/6N mice. Two-way ANOVA followed by Bonferroni post hoc test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM). RF right front, LF left front, RH right hind, LH left hind.

Figure 3

Comparison of interlimb coordination parameters between C57BL/6N and DBA/2 at P32. (a) DBA/2 mice showed a decrease in the base of support of both front and hind paws compared to C57BL/6N mice. (b) The stride lengths of LH and RH paws were more in DBA/2 than C57BL/6N mice. (c) The print position of the right paws was less in DBA/2 compared to C57BL/6N mice. (d) DBA/2 mice used less single and lateral support compared to C57BL/6N mice. (e) The phase dispersion percentages of LF- > LH, LH- > RH and RF- > RH were more in DBA/2 than C57BL/6N mice. (f) The number of patterns in DBA/2 mice was fewer, but the regularity index was higher than in C57BL/6N mice. (g) DBA/2 mice showed lower step sequence percentages of Aa and Cb and a higher percentage of Ab compared to C57BL/6N mice. Two-way ANOVA followed by Bonferroni post hoc test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM). RF right front, LF left front, RH right hind, LH left hind.

Figure 4

Comparison of run characteristics and kinetic, temporal and spatial parameters between C57BL/6N and DBA/2 mice at P42. (a) DBA/2 mice showed a significant increase in the average speed and cadence, but no difference in the number of steps compared to C57BL/6N mice. (b,c) DBA/2 mice showed an increase in the body speed (b) and swing speed (c) of all paws compared to C57BL/6N mice. (d) DBA/2 mice showed a significant decrease in the stand time of LF and RF paws. (e) DBA/2 mice showed a significant decrease in the swing time of all paws. (f) DBA/2 mice showed a significant decrease in the step cycle of LF, RF and RH paws. (g) DBA/2 mice showed a significant decrease in the maximum contact at (%) of both LF and RF paws compared to C57BL/6N mice. (h,i) DBA/2 mice showed an increase in the print area of all paws (h) and a decrease in the maximum intensity of the RH paw compared to C57BL/6N mice. (i). Two-way ANOVA followed by Bonferroni post hoc test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM). RF right front, LF left front, RH right hind, LH left hind.

Figure 5

Comparison of interlimb coordination parameters between C57BL/6N and DBA/2 mice at P42. (a) DBA/2 mice showed a decrease in the base of support of both front and hind paws compared to C57BL/6N mice. (b) The stride lengths of both LH and RH paws were higher in DBA/2 than C57BL/6N mice. (c) The print positions of both left and right paws were lower in DBA/2 compared to C57BL/6N mice. (d) DBA/2 mice used less single but more three-paws support compared to C57BL/6N mice. (e) The phase dispersion percentages of LF- > LH, LH- > RH and RF- > RH were higher in DBA/2 than C57BL6N mice. (f) The number of patterns and regularity index were higher in DBA/2 than C57BL/6N mice. (g) DBA/2 mice showed lower step sequence percentages of Aa and Cb and a higher percentage of Ab compared to C57BL/6N mice. Two-way ANOVA followed by Bonferroni post hoc test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM). RF right front, LF left front, RH right hind, LH left hind.

Figure 6

Comparison of run characteristics and kinetic, temporal and spatial parameters between P32 and P42 FVB/N mice. (a,b) No differences were seen in the average speed, cadence, number of steps (a) or body speed (b) between P32 and P42 FVB/N mice. (c) The swing speed of the RH paw was significantly less at P42 than P32. (d) No difference was seen in the stand time between P32 and P42 FVB/N mice. (e) The swing time of all paws at P42 was longer than at P32. (f) No difference was seen in the step cycle between P32 and P42 FVB/N mice. (g) The maximum contact at (%) of the LF paw was significantly higher at P42 than at P32. (h,i) The print area (h) and the maximum intensity (i) at P42 were lower than at P32. Two-way ANOVA followed by Bonferroni post hoc test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM). RF right front, LF left front, RH right hind, LH left hind.

Figure 7

Comparison of interlimb coordination parameters between P32 and P42 FVB/N mice. (a) No difference was seen in the base of support of either front or hind paws between P32 and P42. (b) The stride lengths of the front paws at P42 were significantly longer than at P32. The stride lengths of hind paws at P42 showed only a borderline significant increase compared to P32. (c) No difference was seen in the print position of either left or right paws between P32 and P42. (d) The percentage of support on three paws was significantly lower at P42 than at P32. The support on single and diagonal was borderline significantly increased at P42. (e–g) No differences were seen in the phase dispersion (e), number of patterns, regularity index (f) or step sequence (g) between P32 and P42 FVB/N mice. Two-way ANOVA followed by Bonferroni post hoc test, *p ≤ 0.05. A red rectangle indicates a significant difference between sexes within a strain (see Supplementary Table S1). Error bars indicate the standard error of the mean (SEM). RF right front, LF left front, RH right hind, LH left hind.