Voluntary Wheel Running in Mice

Abstract

Voluntary wheel running in the mouse is used to assess physical performance and endurance and to model exercise training as a way to enhance health. Wheel running is a voluntary activity in contrast to other experimental exercise models in mice, which rely on aversive stimuli to force active movement. This protocol consists of allowing mice to run freely on the open surface of a slanted, plastic saucer-shaped wheel placed inside a standard mouse cage. Rotations are electronically transmitted to a USB hub so that frequency and rate of running can be captured via a software program for data storage and analysis for variable time periods. Mice are individually housed so that accurate recordings can be made for each animal. Factors such as mouse strain, gender, age, and individual motivation, which affect running activity, must be considered in the design of experiments using voluntary wheel running.

Keywords: exercise training; exercised-induced health benefits; mouse fitness testing; running endurance; voluntary wheel running.

Figure 1

The free-wheel running apparatus (Med Associates Inc, St Albans, VT, USA) fits into a standard size mouse cage. Other systems, such as the Mouse Home Cage Running Wheel (Columbus Instruments, Columbus, OH) are available that provide a similar means for voluntary wheel running.

Figure 2

Wheel running distance varied in male mice by strain, age, and individual mouse. Mice were either CB6F1 or C57BL/6. Each bar represents one mouse. All mice ran for a three-day period.

Figure 3

The running wheel unit is placed in a cage where the hanging food hopper has been replaced with a thick glass cup placed on the cage floor as a food holder.

Figure 4

The running frequency actogram shows that four mice differed in the amount of time and distance on the running wheel. Running occurred almost exclusively during the active dark cycle.

Figure 5

Five-month-old C57BL/6 male mice had a fluctuating running distance pattern over a 21 day period with an initial burst of activity up to day 3 or 4, followed by several bouts of decreasing and increasing activity over the remaining time period. Each line represents the activity of one mouse.