Description
Measuring the metabolic costs of exercise and locomotion
The new Mouse Respirometry Treadmill integrates seamlessly with Sable’s proven pull-mode respirometry systems, delivering industry-best response time. This provides researchers with the most accurate picture of metabolic changes during exercise.
Flexible Design
The treadmill provides a high degree of adjustability for speed (up to 80 m/min), acceleration rate (0 to 100 m/min2), and incline (0˚ to +/-25˚). Mouse metabolic rates are measured within the 1.85 liter respirometry chamber, which rests on top of the treadmill belt, and provides the mouse with a 7 cm x 33 cm running lane. To eliminate contamination from the operator’s breathing, the treadmill lane and respirometry chamber are encased in a clear acrylic air shield perfused at 10 liters per minute with uncontaminated air. The respirometry chamber design breaks the air boundary layer likely to trap respiratory gasses against the belt surface when used at higher speeds (>15 m/min), allowing complete gas recovery for analyses. The air shield will also allow easy application of customized atmospheres (e.g. hypoxia or hyperoxia).
Applications
The Mouse Respirometry Treadmill provides precise and accurate VO2, RQ and RER measurements, revealing changes in fuel use at different speeds and inclines. The high air flow rate of 3.5 liters per minute yields a time constant of 32 seconds (or 114 complete air exchanges per hour) with the use of Sable Promethion gas analyzers.
Animal safety
The treadmill is designed with animal safety as a priority. The shock grid is programmable and cannot exceed 4 mA current. Standard test runs used only 1 mA and required only one or two sessions to train naive animals to run with consistent rhythm. An emergency stop can be initiated with access to the experimental animal in less than 2 seconds. A spring-loaded edge-trim guard with 2 cm soft rubber blade, running flush against the belt surface, can be fitted to prevent the mouse’s tail from getting trapped between the belt and the respirometry chamber’s rear wall.
This graph demonstrates the response time, stability, and accuracy of Promethion respiratory gas measurements while the treadmill is operating at 20 meters per minute. The injection rates (0-10 ml/min) of a known calibration gas (20% CO2 + N2) was altered as indicated.