Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland.
Am J Physiol Renal Physiol. 2019 Apr 1;316(4):F635-F645. doi: 10.1152/ajprenal.00254.2018. Epub 2019 Jan 16.
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 s at 21% O; 90 s hypoxia, 6.5% O at nadir) for 4 h [acute IH (AIH)] or to chronic IH (CIH) for 8 h/day for 2 wk. 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 (Po). AIH had no effect on MAP (123 ± 14 vs. 129 ± 14 mmHg, means ± SE, sham vs. IH). The CIH group was hypertensive (122 ± 9 vs. 144 ± 15 mmHg, P < 0.05). Glomerular filtration rate (GFR) (0.92 ± 0.27 vs. 1.33 ± 0.33 ml/min), RBF (3.8 ± 1.5 vs. 7.2 ± 2.4 ml/min), and transported sodium (TNa) (132 ± 39 vs. 201 ± 47 μmol/min) were increased in the AIH group (all P < 0.05). In the CIH group, GFR (1.25 ± 0.28 vs. 0.86 ± 0.28 ml/min, P < 0.05) and TNa (160 ± 39 vs. 120 ± 40 μmol/min, P < 0.05) were decreased, while RBF (4.13 ± 1.5 vs. 3.08 ± 1.5 ml/min) was not significantly different. Oxygen consumption (QO) was increased in the AIH group (6.76 ± 2.60 vs. 13.60 ± 7.77 μmol/min, P < 0.05), but it was not significantly altered in the CIH group (3.97 ± 2.63 vs. 6.82 ± 3.29 μmol/min). Cortical Po was not significantly different in the AIH group (46 ± 4 vs. 46 ± 3 mmHg), but it was decreased in the CIH group (44 ± 5 mmHg vs. 38 ± 2 mmHg, P < 0.05). For AIH, renal oxygen homeostasis was preserved through a maintained balance between O supply (RBF) and consumption (GFR). For CIH, mismatched TNa and QO reflect inefficient O utilization and, thereby, sustained decrease in cortical Po.
慢性肾脏病（CKD）在超过 50%的阻塞性睡眠呼吸暂停（OSA）患者中发生。然而，间歇性低氧（IH）对肾功能和氧平衡的影响尚不清楚。雄性 Sprague-Dawley 大鼠接受 IH（21% O 时 270 s；最低点时 6.5% O，90 s 缺氧）4 h [急性 IH（AIH）]或每天接受 8 h 的慢性 IH，进行 2 周。动物接受麻醉并接受手术准备，以测量平均动脉压（MAP）以及左肾排泄功能、肾血流（RBF）和肾氧张力（Po）。AIH 对 MAP 没有影响（123 ± 14 与 129 ± 14 mmHg，平均值 ± SE，假手术与 IH）。CIH 组高血压（122 ± 9 与 144 ± 15 mmHg，P < 0.05）。肾小球滤过率（GFR）（0.92 ± 0.27 与 1.33 ± 0.33 ml/min）、RBF（3.8 ± 1.5 与 7.2 ± 2.4 ml/min）和转运钠（TNa）（132 ± 39 与 201 ± 47 μmol/min）在 AIH 组增加（均 P < 0.05）。在 CIH 组中，GFR（1.25 ± 0.28 与 0.86 ± 0.28 ml/min，P < 0.05）和 TNa（160 ± 39 与 120 ± 40 μmol/min，P < 0.05）降低，而 RBF（4.13 ± 1.5 与 3.08 ± 1.5 ml/min）无显著差异。AIH 组的耗氧量（QO）增加（6.76 ± 2.60 与 13.60 ± 7.77 μmol/min，P < 0.05），但在 CIH 组中无显著变化（3.97 ± 2.63 与 6.82 ± 3.29 μmol/min）。AIH 组皮质 Po 无显著差异（46 ± 4 与 46 ± 3 mmHg），但在 CIH 组中降低（44 ± 5 mmHg 与 38 ± 2 mmHg，P < 0.05）。对于 AIH，通过维持 O 供应（RBF）和消耗（GFR）之间的平衡来维持肾脏的氧平衡。对于 CIH，不匹配的 TNa 和 QO 反映了低效的 O 利用，从而导致皮质 Po 的持续下降。
