A Low-Cost Metabolic Apparatus for Student Labs: Measuring Oxygen Consumption and Ventilation in Conscious Mice

Hands-on experience in measuring core physiological parameters like oxygen consumption (VO₂) is essential for deep conceptual understanding, yet the prohibitive cost of commercial systems often excludes such experiments from science curricula. To bridge this gap, we developed and implemented a ready-to-use educational module centered on a simple, low-cost metabolic apparatus. The apparatus, constructed from commercially available components, enables direct measurement of VO₂ and respiratory parameters in conscious mice by students. Moreover, the apparatus was successfully used to detect and quantify the opposing physiological effects of two classic metabolic-modulating drugs: levothyroxine sodium (increasing VO₂ and minute ventilation) and chlorpromazine hydrochloride (decreasing VO₂, respiratory frequency, and ventilation). This module transforms abstract principles of energy metabolism, respiratory control, and pharmacology into an investigable, inquiry-based learning experience. The apparatus features straightforward assembly and operation, and is accompanied by a comprehensive instructional manual. These attributes render it particularly well suited for integration into undergraduate and graduate physiology and pharmacology laboratories, thereby broadening access to advanced physiological measurement techniques.