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Differences in mitochondrial function between brain and heart of senile rats exposed to acute hypobaric hypoxia. Role of nitric oxide. Exp Gerontol 2023; 173:112100. [PMID: 36690048 DOI: 10.1016/j.exger.2023.112100] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Rat brain and heart display different endogenous protective responses against hypobaric hypoxia in an age-dependent way. The aim of the present work was to evaluate the effects of acute hypobaric hypoxia (HH, 48 h) on brain and heart mitochondrial function as well as the participation of nitric oxide (NO) in old rats (22-month old). Cortical mitochondria from rats exposed to HH decreased respiratory rates (37 %, state 3) and membrane potential (20 %), but NO and H2O2 production increased by 48 %, and 23 %, respectively. Hippocampal mitochondria preserved O2 consumption and H2O2 production, decreased membrane potential (18 %) and increased NO production (46 %). By contrast, HH decreased NO production (53 %) in mitochondria from left heart ventricles associated with increased cytochrome oxidase activity (39 %) and decreased NADPH oxidase activity (31 %). Also, a tendency to increase complex I-III (24 %) and complex II-III (65 %) activity was observed. In conclusion, after HH hippocampal and cortical mitochondria showed mild uncoupling and increased NO production. However, only the hippocampus preserved O2 consumption and H2O2 levels. Interestingly, heart mitochondria showed a decreased ROS production through increased cytochrome oxidase activity associated with a decrease in NO production. This may be interpreted as a self-protective mechanism against hypoxia.
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Manukhina EB, Tseilikman VE, Tseilikman OB, Komelkova MV, Kondashevskaya MV, Goryacheva AV, Lapshin MS, Platkovskii PO, Alliluev AV, Downey HF. Intermittent hypoxia improves behavioral and adrenal gland dysfunction induced by posttraumatic stress disorder in rats. J Appl Physiol (1985) 2018; 125:931-937. [DOI: 10.1152/japplphysiol.01123.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nonpharmacological treatments of stress-induced disorders are promising, since they enhance endogenous stress defense systems, are free of side effects, and have few contraindications. The present study tested the hypothesis that intermittent hypoxia conditioning (IHC) ameliorates behavioral, biochemical, and morphological signs of experimental posttraumatic stress disorder (PTSD) induced in rats with a model of predator stress (10-day exposure to cat urine scent, 15 min daily followed by 14 days of stress-free rest). After the last day of stress exposure, rats were conditioned in an altitude chamber for 14 days at a 1,000-m simulated altitude for 30 min on day 1 with altitude and duration progressively increasing to 4,000 m for 4 h on day 5. PTSD was associated with decreased time spent in open arms and increased time spent in closed arms of the elevated X-maze, increased anxiety index, and increased rate of freezing responses. Functional and structural signs of adrenal cortex degeneration were also observed, including decreased plasma concentration of corticosterone, decreased weight of adrenal glands, reduced thickness of the fasciculate zone, and hydropic degeneration of adrenal gland cells. The thickness of the adrenal fasciculate zone negatively correlated with the anxiety index. IHC alleviated both behavioral signs of PTSD and morphological evidence of adrenal cortex dystrophy. Also, IHC alone exerted an antistress effect, which was evident from the increased time spent in open arms of the elevated X-maze and a lower number of rats displaying freezing responses. Therefore, IHC of rats with experimental PTSD reduced behavioral signs of the condition and damage to the adrenal glands. NEW & NOTEWORTHY Intermittent hypoxia conditioning (IHC) has been shown to be cardio-, vaso-, and neuroprotective. For the first time, in a model of posttraumatic stress disorder (PTSD), this study showed that IHC alleviated both PTSD-induced behavioral disorders and functional and morphological damage to the adrenal glands. Also, IHC alone exerted an antistress effect. These results suggest that IHC may be a promising complementary treatment for PTSD-associated disorders.
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Affiliation(s)
- Eugenia B. Manukhina
- School of Medical Biology, South Ural State University, Chelyabinsk, Russia
- Laboratory for Regulatory Mechanisms of Stress and Adaptation, Institute of General Pathology and Pathophysiology, Moscow, Russia
- Department of Anatomy and Physiology, University of North Texas Health Science Center, Fort Worth, Texas
| | | | - Olga B. Tseilikman
- School of Medical Biology, South Ural State University, Chelyabinsk, Russia
| | - Maria V. Komelkova
- School of Medical Biology, South Ural State University, Chelyabinsk, Russia
| | - Marina V. Kondashevskaya
- Laboratory for Immunomorphology of Inflammation, FSBSI Research Institute of Human Morphology, Moscow, Russia
| | - Anna V. Goryacheva
- Laboratory for Regulatory Mechanisms of Stress and Adaptation, Institute of General Pathology and Pathophysiology, Moscow, Russia
| | - Maxim S. Lapshin
- School of Medical Biology, South Ural State University, Chelyabinsk, Russia
| | | | | | - H. Fred Downey
- School of Medical Biology, South Ural State University, Chelyabinsk, Russia
- Department of Anatomy and Physiology, University of North Texas Health Science Center, Fort Worth, Texas
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Mohammed R, Salinas CE, Giussani DA, Blanco CE, Cogolludo AL, Villamor E. Acute hypoxia-reoxygenation and vascular oxygen sensing in the chicken embryo. Physiol Rep 2017; 5:5/22/e13501. [PMID: 29146864 PMCID: PMC5704079 DOI: 10.14814/phy2.13501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 10/23/2017] [Indexed: 02/03/2023] Open
Abstract
Fetal/perinatal hypoxia is one of the most common causes of perinatal morbidity and mortality and is frequently accompannied by vascular dysfunction. However, the mechanisms involved have not been fully delineated. We hypothesized that exposure to acute hypoxia‐reoxygenation induces alterations in vascular O2 sensing/signaling as well as in endothelial function in the chicken embryo pulmonary artery (PA), mesenteric artery (MA), femoral artery (FA), and ductus arteriosus (DA). Noninternally pipped 19‐day embryos were exposed to 10% O2 for 30 min followed by reoxygenation with 21% O2 or 80% O2. Another group was constantly maintained at 21% O2 or at 21% O2 for 30 min and then exposed to 80% O2. Following treatment, responses of isolated blood vessels to hypoxia as well as endothelium‐dependent (acetylcholine) and ‐independent (sodium nitroprusside and forskolin) relaxation were investigated in a wire myograph. Hypoxia increased venous blood lactate from 2.03 ± 0.18 to 15.98 ± 0.73 mmol/L (P < 0.001) and reduced hatchability to 0%. However, ex vivo hypoxic contraction of PA and MA, hypoxic relaxation of FA, and normoxic contraction of DA were not significantly different in any of the experimental groups. Relaxations induced by acetylcholine, sodium nitroprusside, and forskolin in PA, MA, FA, and DA rings were also similar in the four groups. In conclusion, exposure to acute hypoxia‐reoxygenation did not affect vascular oxygen sensing or reactivity in the chicken embryo. This suggests that direct effects of acute hypoxia‐reoxygenation on vascular function does not play a role in the pathophysiology of hypoxic cardiovascular injury in the perinatal period.
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Affiliation(s)
- Riazuddin Mohammed
- Department of Pediatrics, Maastricht University Medical Center (MUMC+) School for Oncology and Developmental Biology (GROW), Maastricht, the Netherlands
| | - Carlos E Salinas
- Instituto Boliviano de Biología de Altura, Facultad de Medicina, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Dino A Giussani
- Department of Physiology Development & Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Carlos E Blanco
- Department of Neonatology, National Maternity Hospital, Dublin, Ireland
| | - Angel L Cogolludo
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES) Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Eduardo Villamor
- Department of Pediatrics, Maastricht University Medical Center (MUMC+) School for Oncology and Developmental Biology (GROW), Maastricht, the Netherlands
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Manukhina EB, Jasti D, Vanin AF, Downey HF. Intermittent hypoxia conditioning prevents endothelial dysfunction and improves nitric oxide storage in spontaneously hypertensive rats. Exp Biol Med (Maywood) 2011; 236:867-73. [PMID: 21652603 DOI: 10.1258/ebm.2011.011023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although intermittent hypoxia is often associated with hypertension, experimental and clinical studies have demonstrated definite antihypertensive effects of some intermittent hypoxia conditioning (IHC) regimens. Mechanisms of this antihypertensive response are unknown. Endothelial dysfunction related to disturbed synthesis and/or reduced availability of nitric oxide (NO) has been linked to hypertension. Thus, experiments were conducted to determine if IHC can improve endothelium-dependent relaxation and formation of releasable vascular NO stores of young (4-8-week-old) spontaneously hypertensive rats (SHR). Rats were subjected to either IHC (9.5-10% O(2), 5-10 min, 5-8 times per day, 20 d) or to sham conditioning. Endothelium-dependent relaxation to acetylcholine was measured in norepinephrine-precontracted, isolated aortic rings, and the size of NO stores was evaluated by percent relaxation to N-acetylcysteine (NAC), which releases stored NO. The capacity of aortic rings for NO storage was evaluated by the relaxation to NAC after prior incubation with an NO donor. IHC significantly suppressed the development of hypertension in young SHR. Endothelial function decreased from 54.7 ± 4.6% to 28.1 ± 6.4% relaxation to acetylcholine after 20 d of sham IHC, whereas endothelial function was sustained (60.3 ± 6.0% relaxation) in IHC rats. IHC also induced formation of available NO stores and enhanced the capacity of aortic rings to store NO. Therefore, the antihypertensive effect of IHC in young SHR is associated with prevention of endothelial dysfunction and with increased accumulation of NO stores in vascular walls.
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Affiliation(s)
- Eugenia B Manukhina
- Department of Integrative Physiology, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA
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Goryacheva AV, Kruglov SV, Pshennikova MG, Smirin BV, Malyshev IY, Barskov IV, Viktorov IV, Downey HF, Manukhina EB. Adaptation to intermittent hypoxia restricts nitric oxide overproduction and prevents beta-amyloid toxicity in rat brain. Nitric Oxide 2010; 23:289-99. [DOI: 10.1016/j.niox.2010.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 08/18/2010] [Accepted: 08/24/2010] [Indexed: 11/17/2022]
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Serebrovskaya TV, Manukhina EB, Smith ML, Downey HF, Mallet RT. Intermittent hypoxia: cause of or therapy for systemic hypertension? Exp Biol Med (Maywood) 2008; 233:627-50. [PMID: 18408145 DOI: 10.3181/0710-mr-267] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
During acute episodes of hypoxia, chemoreceptor-mediated sympathetic activity increases heart rate, cardiac output, peripheral resistance and systemic arterial pressure. However, different intermittent hypoxia paradigms produce remarkably divergent effects on systemic arterial pressure in the post-hypoxic steady state. The hypertensive effects of obstructive sleep apnea (OSA) vs. the depressor effects of therapeutic hypoxia exemplify this divergence. OSA, a condition afflicting 15-25% of American men and 5-10% of women, has been implicated in the pathogenesis of systemic hypertension and is a major risk factor for heart disease and stroke. OSA imposes a series of brief, intense episodes of hypoxia and hypercapnia, leading to persistent, maladaptive chemoreflex-mediated activation of the sympathetic nervous system which culminates in hypertension. Conversely, extensive evidence in animals and humans has shown controlled intermittent hypoxia conditioning programs to be safe, efficacious modalities for prevention and treatment of hypertension. This article reviews the pertinent literature in an attempt to reconcile the divergent effects of intermittent hypoxia therapy and obstructive sleep apnea on hypertension. Special emphasis is placed on research conducted in the nations of the former Soviet Union, where intermittent hypoxia conditioning programs are being applied therapeutically to treat hypertension in patients. Also reviewed is evidence regarding mechanisms of the pro- and anti-hypertensive effects of intermittent hypoxia.
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