Hypoxic exercise tolerance in mice

This project, which is funded by NIH, is an investigation of the biochemical, physiological and genetic basis of hypoxic exercise tolerance in mice. We use a genetic model for hypoxic treadmill performance originally described by our collaborator, Dale McCall (UNCW, Department of Anthropology). Following 8 weeks of exposure to hypobaric hypoxia (1/2 atmospheric PO2), mice of different genotypes have dramatically different capacities for hypoxic treadmill exercise. The best performing mice, can run on a treadmill (40 cm/s; 15° incline) under hypoxia for >2 h, while the worst performing mice fatigue following several minutes of exercise. Two genes of major effect largely account for the variance in performance. While we do not yet know the identity of the genes of major effect, the model constitutes a tractable system for examining the mechanistic basis of acclimation to hypobaric hypoxia and the limits of endurance exercise.

We have focused on the blood, skeletal muscle and cardiac muscle, and we are using a variety of techniques to examine aspects of blood chemistry, as well as remodeling of skeletal and cardiac muscle structure and function. In addition, we are using cDNA microarrays to examine patterns of gene expression in skeletal muscle.