Gait Analysis of Age-dependent Motor Impairments in Mice with Neurodegeneration

Summary

In this study, we demonstrate the use of kinematic gait analysis based on ventral plane imaging to monitor the subtle changes in motor coordination as well as the progression of neurodegeneration with advancing age in mouse models (e.g., endophilin mutant mouse lines).

Abstract

Motor behavior tests are commonly used to determine the functional relevance of a rodent model and to test newly developed treatments in these animals. Specifically, gait analysis allows recapturing disease relevant phenotypes that are observed in human patients, especially in neurodegenerative diseases that affect motor abilities such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and others. In early studies along this line, the measurement of gait parameters was laborious and depended on factors that were hard to control (e.g., running speed, continuous running). The development of ventral plane imaging (VPI) systems made it feasible to perform gait analysis at a large scale, making this method a useful tool for the assessment of motor behavior in rodents. Here, we present an in-depth protocol of how to use kinematic gait analysis to examine the age-dependent progression of motor deficits in mouse models of neurodegeneration; mouse lines with decreased levels of endophilin, in which neurodegenerative damage progressively increases with age, are used as an example.

Introduction

Neurodegenerative diseases impose a significant burden on patients, families, and society, and will become of even greater concern as life expectancy increases, and the world population continues to age. One of the most common symptoms of neurodegenerative diseases are balance and mobility problems. Thus, characterization of motor behavior in aging mammalian (e.g., rodent) models, and/or models showing neurodegenerative phenotypes, is a valuable tool to demonstrate the in vivo relevance of the specific animal model(s), or therapeutic treatments that aim to improve the disease symptoms. Almost every approach to treat neurodegenerative diseases ultimat....

Protocol

All animal experiments reported here are conducted according to the European Guidelines for animal welfare (2010/63/EU) with approval by the Niedersächsisches Landesamt für Verbraucherschutz und Lebensmittelsicherheit (LAVES), registration number 14/1701.

1. Study Design

1. As animal behavior work requires careful planning, consider the following parameters while designing the experiment.
   1. Number of animals needed per group.
      1. Use a statistical software (e.g., PASS, EDA, or GPower) to calculate the required group size.
         NOTE: The group size depends on the variation between animals a....

Results

To illustrate the use of kinematic gait analysis, we have performed gait analysis on WT C57BL/6J mice with advancing age, as well as several endophilin mutant lines, using commercially available instrumentation and software (please refer to the Table of Materials). In this setup, a high-speed camera under a transparent treadmill records the running of a mouse (Figure 1A). The software then recognizes the contrast between the red colored paws .......

Discussion

Studying the motor coordination is a useful approach in the characterization of models of neurodegenerative diseases, especially for diseases like PD in which motor coordination is severely affected. With the help of a kinematic gait analysis functional assay, we can identify subtle changes in the gait of animals at the onset of locomotion problems, or in models with weak neurodegeneration and hence relatively modest phenotype. Given the wide range of phenotypes in various models of neurodegenerative diseases that encomp.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
DigiGait	Mouse Specifics, Inc., Framingham, Massachusetts, USA		DigiGait Imager and Analysis Software are included with the hardware
non-transparent blanket or dark cloth			cover the test chamber to reduce the animal's feeling of exposure/stress
balance	e.g. Satorius		balance with 0.1 g accuracy and a maximum load of at least 100 g
red finger paint	e.g. Kreul or Staedtler		for increasing the contrast between paws and animal’s body
small paint brush			soft brush to apply finger paint to the animal paws
diluted detergent			for cleaning
disinfectant, e.g. Meliseptol or 70% ethanol	e.g. B.Braun		for desinfection