Peer-Reviewed Journal Details
Mandatory Fields
O'Neill, Julie; Jasionek, Greg; Drummond, Sarah E.; Brett, Orla; Lucking, Eric F.; Abdulla, Mohammed A.; O'Halloran, Ken D.
American Journal of Physiology (Renal)
Renal cortical oxygen tension is decreased following exposure to long-term but not short-term intermittent hypoxia in the rat
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Optional Fields
Chronic kidney disease Obstructive sleep apnea Intermittent hypoxia Renal function Oxygen homeostasis
Chronic kidney disease (CKD) occurs in more than 50% of patients with obstructive sleep apnea (OSA). However, the impact of intermittent hypoxia (IH) on renal function and oxygen homeostasis is unclear. Male Sprague Dawley rats were exposed to IH (270 secs at 21% O2; 90 secs hypoxia, 6.5% O2 at nadir) for 4 h (AIH) or to chronic IH (CIH) for 8h/day for 2 weeks. Animals were anesthetized and surgically prepared for the measurement of mean arterial pressure (MAP), and left renal excretory function, renal blood flow (RBF), and renal oxygen tension (PO2). AIH had no effect on MAP (123±14 versus (v) 129±14mmHg, mean±SEM, sham v IH). The CIH group were hypertensive (122±9 v 144±15mmHg, P<0.05). Glomerular filtration rate (GFR) (0.92±0.27 v 1.33±0.33ml/min), RBF (3.8±1.5 v 7.2±2.4ml/min) and transported sodium (TNa) (132±39 v 201±47μmol/min) were increased in the AIH group (all P<0.05). In the CIH group, GFR (1.25±0.28 v 0.86±0.28ml/min, P<0.05) and TNa (160±39 v 120±40μmol/min, P<0.05) were decreased, while RBF (4.13±1.5 v 3.08±1.5ml/min) was not significantly different. Oxygen consumption (QO2) was increased in the AIH group (6.76±2.60 v 13.60±7.77μmol/min, P<0.05), but was not significantly altered in the CIH group (3.97±2.63 v 6.82±3.29μmol/min). Cortical PO2 was not significantly different in the AIH group (46±4 v 46±3mmHg), but was decreased in the CIH group (44±5mmHg v 38±2mmHg, P<0.05). AIH: Renal oxygen homeostasis was preserved through a maintained balance between O2 supply (RBF) and consumption (GFR). CIH: Mismatched TNa and QO2 reflects inefficient O2 utilization and thereby sustained decrease in cortical PO2.
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