0030 Abnormal Energy Metabolism Persists After Removal of Chronic Resistive Loading in Rats

Introduction Obstructive sleep-disordered breathing (SDB) in rats leads to a substantial cascade of complex endocrine derangements that affect longitudinal growth, body weight, energy metabolism, and decreased body temperature (Tb). During upper airway obstruction (AO) the respiratory system undergoes adaptive changes in order to maintain respiratory homeostasis. Here, we investigated the effects of AO obstruction removal (OR) on energy cost and thermogenic capacity required to maintain respiratory homeostasis. Methods The tracheae of 22-day-old rats were narrowed; on day 14 the AO group was randomized and OR was surgically performed on half of the animals. Animals were monitored for 7 weeks; energy expenditure (EE), ventilation, and Tb were measured by metabolic system, plethysmography, and telemetry system, respectively. Brown adipose tissue (BAT) recruitment was performed following norepinephrine injection. Temperature-dependent changes in EE were tested by modified Scholander procedure, and BAT uncoupling protein 1 (UCP1) level was analyzed. Results Energy expenditure (EE) increased by 45% and 15% in the AO and OR groups, respectively (p