BAZE, Monica*; HAYES, Jack P. ; WEBER, Lee A.; University of Nevada, Reno; University of Nevada, Reno; University of Nevada, Reno: Gene Expression of House Mice Acclimated to Chronic Hypoxia

Chronic hypoxia is a significant physiological challenge to mammals in high altitude environments (2500 m or more). To accommodate the decrease in O₂ partial pressure, mammals that acclimatize to high altitudes remodel their cardiovascular and other organ systems, change their blood chemistry, and adjust their metabolism to maintain O₂ homeostasis. These acclimatization responses likely require changes in gene expression. Gene expression responses of in vitro cell cultures (e.g., hepatocytes) have helped illuminate the molecular and cellular mechanisms of hypoxia responses. Likewise, studies on ischemic organs have illustrated how particular organs respond to hypoxia. However, the gene expression profiles associated with in vivo, whole animal exposure to hypoxia may be quite different then what is found in in vitro or ischemic studies. To better understand in vivo gene expression associated with acclimatization to chronic hypoxia, we subjected 36 male house mice to oxygen partial pressures corresponding to 1400 m, 3000 m, or 4500 m. After 32 days of exposure, tissue samples were taken from these mice for RNA analysis on GeneChip Mouse Genome Arrays (Affymetrix). We will present data on the effect of chronic hypoxia on gene expression in the liver. This study will complement further work that is being carried out on feral house mice living at high altitudes in South America. Not only do we hope to gain a better understanding of physiological responses to hypoxia, but to eventually determine which of these responses represent acclimatization versus which represent potential adaptations.