Article
The CatWalk XT is a valid tool for objective assessment of gait and motor function after controlled cortical impact in mice
Der CatWalk XT ist eine valide Methode zur Beurteilung von Gleichgewicht und motorischer Funktion nach experimentellem Schädel-Hirn-Trauma im Mausmodell
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Published: | June 26, 2020 |
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Objective: In order to further elucidate the pathophysiology of traumatic brain injury (TBI) and test new treatment options different animal models are available, the controlled cortical impact (CCI) model being one of the most frequently used. However, objectively assessing functional outcome after CCI in animals is challenging; therefore, we evaluated the value of the CatWalk XT in assessing gait and motor function after CCI in mice.
Methods: C57/Bl6 wildtype mice were subjected to either right parietal craniotomy followed by controlled cortical impact (tip diameter 2mm, impact depth 1mm, velocity 8m/s, contact time 150ms) or craniotomy only. A total of 103 parameters of motor function and gait were automatically analyzed using the CatWalk XT test one, three and seven days after CCI.
Results: Gait and motor function were significantly more impaired and contusion volumes significantly higher in animals subjected to CCI compared to animals that underwent craniotomy alone (i.e. change in left hindpaw maximum intensity on day 3: 15.8 +/- 5.1 vs. -3.2 +/- 6.0, p=0.02; change in left hindpaw print area on day 3: 0.062 +/- 0.039 cm2 vs. 0.002 +/- 0.041 cm2, p=0.004; change in left frontpaw maximum intensity on day 3: 13.8 +/- 3.5 vs. 1.2 +/- 4.3, p=0.04). Although CCI is a model for focal injury, the effect on gait and motor function was bilateral and diffuse. Impairments of static parameters were most severe within the first three days after CCI and resolved thereafter while impairments of dynamic parameters persisted until day seven after trauma induction.
Conclusion: CatWalk XT is a valuable tool for observer-independent and automated assessment of gait and motor function after CCI in mice. Spatial and temporal profiles of impairments of gait and motor function induced by CCI with the chosen parameters are similar to the ones seen in human patients after TBI; therefore, CCI is a valid model for preclinical evaluation of the effect of possible new treatment strategies on functional motor outcome.