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Neubert E, Rassler B, Hoschke A, Raffort C, Salameh A. Effects of Normobaric Hypoxia and Adrenergic Blockade over 72 h on Cardiac Function in Rats. Int J Mol Sci 2023; 24:11417. [PMID: 37511176 PMCID: PMC10379660 DOI: 10.3390/ijms241411417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/06/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
In rats, acute normobaric hypoxia depressed left ventricular (LV) inotropic function. After 24 h of hypoxic exposure, a slight recovery of LV function occurred. We speculated that prolonged hypoxia (72 h) would induce acclimatization and, hence, recovery of LV function. Moreover, we investigated biomarkers of nitrosative stress and apoptosis as possible causes of hypoxic LV depression. To elucidate the role of hypoxic sympathetic activation, we studied whether adrenergic blockade would further deteriorate the general state of the animals and their cardiac function. Ninety-four rats were exposed over 72 h either to normal room air (N) or to normobaric hypoxia (H). The rodents received infusion (0.1 mL/h) with 0.9% NaCl or with different adrenergic blockers. Despite clear signs of acclimatization to hypoxia, the LV depression continued persistently after 72 h of hypoxia. Immunohistochemical analyses revealed significant increases in markers of nitrosative stress, adenosine triphosphate deficiency and apoptosis in the myocardium, which could provide a possible explanation for the absence of LV function recovery. Adrenergic blockade had a slightly deteriorative effect on the hypoxic LV function compared to the hypoxic group with maintained sympathetic efficacy. These findings show that hypoxic sympathetic activation compensates, at least partially, for the compromised function in hypoxic conditions, therefore emphasizing its importance for hypoxia adaptation.
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Affiliation(s)
- Elias Neubert
- Carl-Ludwig-Institute of Physiology, University of Leipzig, 04103 Leipzig, Germany; (E.N.); (A.H.)
| | - Beate Rassler
- Carl-Ludwig-Institute of Physiology, University of Leipzig, 04103 Leipzig, Germany; (E.N.); (A.H.)
| | - Annekathrin Hoschke
- Carl-Ludwig-Institute of Physiology, University of Leipzig, 04103 Leipzig, Germany; (E.N.); (A.H.)
| | - Coralie Raffort
- Department of Pediatric Cardiology, Heart Centre, University of Leipzig, 04289 Leipzig, Germany; (C.R.); (A.S.)
| | - Aida Salameh
- Department of Pediatric Cardiology, Heart Centre, University of Leipzig, 04289 Leipzig, Germany; (C.R.); (A.S.)
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2
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Macotela L, Naya DE, González-Morales JC, Anaya M, Fajardo V, Manjarrez J. Altitudinal variation in organ mass from three mountain systems: The case of mesquite lizard Sceloporus grammicus. Comp Biochem Physiol A Mol Integr Physiol 2023; 281:111426. [PMID: 37059292 DOI: 10.1016/j.cbpa.2023.111426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 04/10/2023] [Accepted: 04/10/2023] [Indexed: 04/16/2023]
Abstract
High altitude environments provide a fertile ground for investigating the benefits of phenotypic adjustments at several levels of biological organization. Low oxygen partial pressure and low environmental temperature are the main limiting factors that promote phenotypic variation in different organs, such as the lung and heart. Although high-altitude environments act like natural laboratories, most morphological studies conducted to date lack replication. Here, we evaluated organ mass variation in nine populations of Sceloporus grammicus, throughout three altitudinal gradients (mountains) from the Trans-Mexican volcanic belt. A total of 84 individuals from three different altitudes at three different mountains were collected. Then, we used generalized linear models to analyze the pattern of variation in internal organs mass as a function of altitude and temperature. We observed a striking pattern of altitudinal variation in the size of cardiorespiratory organs: while heart mass increased with altitude and decreased with temperature, the lung showed a significant statistical interaction between mountain transect and temperature. Overall, our results support the hypothesis that cardiorespiratory organs should be bigger in populations occurring at higher altitudes. Moreover, the study of different mountain systems allowed us to observe some differences in one mountain in relation to the other two.
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Affiliation(s)
- Luis Macotela
- Doctorado en Ciencias Agropecuarias y Recursos Naturales, Universidad Autónoma del Estado de México, Instituto Literario No. 100, Col. Centro, C. P. 5000 Toluca, Estado de Mexico, Mexico; Instituto para la Conservación de la Cordillera Neovolcánica ante el Cambio Climático, A.C. Calle Lago de Atitlán No. 502, C. P. 50100 Toluca, Estado de México, Mexico
| | - Daniel E Naya
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay; Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - Juan C González-Morales
- Centro Universitario Amecameca, Universidad Autónoma del Estado de México, Instituto Literario 100, Col. Centro, CP 50000 Toluca, Estado de México, Mexico
| | - Mariluz Anaya
- Instituto para la Conservación de la Cordillera Neovolcánica ante el Cambio Climático, A.C. Calle Lago de Atitlán No. 502, C. P. 50100 Toluca, Estado de México, Mexico; Maestría en Ciencias Biológicas, Facultad de Ciencias, Universidad Autónoma del Estado de Mexico, Mexico
| | - Víctor Fajardo
- Instituto para la Conservación de la Cordillera Neovolcánica ante el Cambio Climático, A.C. Calle Lago de Atitlán No. 502, C. P. 50100 Toluca, Estado de México, Mexico
| | - Javier Manjarrez
- Facultad de Ciencias, Universidad Autónoma del Estado de México, Campus El Cerrillo, Carretera Toluca - Ixtlahuaca Km 15.5, Piedras Blancas, 50200 Toluca de Lerdo, Mexico.
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3
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Beckman EJ, Martins F, Suzuki TA, Bi K, Keeble S, Good JM, Chavez AS, Ballinger MA, Agwamba K, Nachman MW. The genomic basis of high-elevation adaptation in wild house mice (Mus musculus domesticus) from South America. Genetics 2022; 220:iyab226. [PMID: 34897431 PMCID: PMC9097263 DOI: 10.1093/genetics/iyab226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/04/2021] [Indexed: 11/14/2022] Open
Abstract
Understanding the genetic basis of environmental adaptation in natural populations is a central goal in evolutionary biology. The conditions at high elevation, particularly the low oxygen available in the ambient air, impose a significant and chronic environmental challenge to metabolically active animals with lowland ancestry. To understand the process of adaptation to these novel conditions and to assess the repeatability of evolution over short timescales, we examined the signature of selection from complete exome sequences of house mice (Mus musculus domesticus) sampled across two elevational transects in the Andes of South America. Using phylogenetic analysis, we show that house mice colonized high elevations independently in Ecuador and Bolivia. Overall, we found distinct responses to selection in each transect and largely nonoverlapping sets of candidate genes, consistent with the complex nature of traits that underlie adaptation to low oxygen availability (hypoxia) in other species. Nonetheless, we also identified a small subset of the genome that appears to be under parallel selection at the gene and SNP levels. In particular, three genes (Col22a1, Fgf14, and srGAP1) bore strong signatures of selection in both transects. Finally, we observed several patterns that were common to both transects, including an excess of derived alleles at high elevation, and a number of hypoxia-associated genes exhibiting a threshold effect, with a large allele frequency change only at the highest elevations. This threshold effect suggests that selection pressures may increase disproportionately at high elevations in mammals, consistent with observations of some high-elevation diseases in humans.
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Affiliation(s)
- Elizabeth J Beckman
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Felipe Martins
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Taichi A Suzuki
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Microbiome Science, Max Planck Institute for Developmental Biology, Tübingen 72076, Germany
| | - Ke Bi
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sara Keeble
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
- Wildlife Biology Program, University of Montana, Missoula, MT 59812, USA
| | - Andreas S Chavez
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Evolution, Ecology, and Organismal Biology and the Translational Data Analytics Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Mallory A Ballinger
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kennedy Agwamba
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael W Nachman
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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Wearing OH, Nelson D, Ivy CM, Crossley DA, Scott GR. Adrenergic control of the cardiovascular system in deer mice native to high altitude. Curr Res Physiol 2022; 5:83-92. [PMID: 35169714 PMCID: PMC8829085 DOI: 10.1016/j.crphys.2022.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/23/2021] [Accepted: 01/23/2022] [Indexed: 12/26/2022] Open
Abstract
Studies of animals native to high altitude can provide valuable insight into physiological mechanisms and evolution of performance in challenging environments. We investigated how mechanisms controlling cardiovascular function may have evolved in deer mice (Peromyscus maniculatus) native to high altitude. High-altitude deer mice and low-altitude white-footed mice (P. leucopus) were bred in captivity at sea level, and first-generation lab progeny were raised to adulthood and acclimated to normoxia or hypoxia. We then used pharmacological agents to examine the capacity for adrenergic receptor stimulation to modulate heart rate (fH) and mean arterial pressure (Pmean) in anaesthetized mice, and used cardiac pressure-volume catheters to evaluate the contractility of the left ventricle. We found that highlanders had a consistently greater capacity to increase fH via pharmacological stimulation of β1-adrenergic receptors than lowlanders. Also, whereas hypoxia acclimation reduced the capacity for increasing Pmean in response to α-adrenergic stimulation in lowlanders, highlanders exhibited no plasticity in this capacity. These differences in highlanders may help augment cardiac output during locomotion or cold stress, and may preserve their capacity for α-mediated vasoconstriction to more effectively redistribute blood flow to active tissues. Highlanders did not exhibit any differences in some measures of cardiac contractility (maximum pressure derivative, dP/dtmax, or end-systolic elastance, Ees), but ejection fraction was highest in highlanders after hypoxia acclimation. Overall, our results suggest that evolved changes in sensitivity to adrenergic stimulation of cardiovascular function may help deer mice cope with the cold and hypoxic conditions at high altitude. High-altitude deer mice have evolved increased aerobic capacity in hypoxia. Cardiovascular regulation was examined in normoxia and chronic hypoxia. Highland mice had increased capacity for β1-adrenergic stimulation of heart rate. Hypoxia reduced vascular α-adrenergic sensitivity in lowland but not highland mice. Cardiac ejection fraction was elevated in highland mice in chronic hypoxia.
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Affiliation(s)
- Oliver H. Wearing
- Department of Biology, McMaster University, Hamilton, ON, Canada
- Corresponding author.
| | - Derek Nelson
- Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - Catherine M. Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Dane A. Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - Graham R. Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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5
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Nguyen KT, Gates CA, Hassell JE, Foxx CL, Salazar SN, Luthens AK, Arnold AL, Elam BL, Elsayed AI, Leblanc M, Adams SC, Lowry CA, Reuter JD. Evaluation of the effects of altitude on biological signatures of inflammation and anxiety- and depressive-like behavioral responses. Prog Neuropsychopharmacol Biol Psychiatry 2021; 111:110331. [PMID: 33891978 DOI: 10.1016/j.pnpbp.2021.110331] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022]
Abstract
Over sixteen million people suffer from a depressive episode annually in the United States, with females affected at twice the rate of males. Little is known about the effects of exposure to high altitude on the risk of development of major depressive disorder, despite reports of higher suicide rates at higher altitudes. We hypothesize that exposure to hypobaric hypoxia at high altitude increases endophenotypes of self-directed suicidal violence, including biological signatures of chronic inflammation and vulnerability to anxiety-like and depressive-like behavioral responses in a sex-specific manner. Biological signatures of inflammation, including granulocyte:lymphocyte ratios, monocyte cell counts, and monocyte:lymphocyte ratios were assessed using complete blood count data, anhedonia, and anxiety- and depressive-like behavioral responses were evaluated. We assessed biological signatures of inflammation and behavioral responses in the open-field test, sucrose preference test, and modified Porsolt forced swim test in young adult male and female Long-Evans and Sprague Dawley rats. All tests were conducted near sea level (374 ft [114 m] elevation) and at moderate-high altitude (5430 ft [1655 m] elevation) during acclimation periods of one, two, three, four, and five weeks following shipment from a sea level animal breeding facility (N = 320, n = 8 per group). Exposure to moderate-high altitude induced a biological signature of increased inflammation, as evidenced by main effects of altitude for: 1) increased granulocyte:lymphocyte ratio; 2) increased count and relative abundance of circulating monocytes; and 3) increased monocyte:lymphocyte ratios. Exposure to moderate-high altitude also increased anhedonia as assessed in the sucrose preference test in both male and female rats, when data were collapsed across strain and time. Among male and female Long Evans rats, exposure to moderate-high altitude increased immobility in the forced swim test, without changing anxiety-like behaviors in the open-field test. Finally, granulocyte:lymphocyte ratios were correlated with anhedonia in the sucrose preference test. These data are consistent with the hypothesis that hypobaric hypoxia at moderate-high altitude induces persistent endophenotypes of self-directed suicidal violence including biological signatures of inflammation, anhedonia, and depressive-like behavioral responses.
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Affiliation(s)
- Kadi T Nguyen
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Chloé A Gates
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - James E Hassell
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Christine L Foxx
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Microbial Exploration, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Stephanie N Salazar
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Amalia K Luthens
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Andrea L Arnold
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Brooke L Elam
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Ahmed I Elsayed
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Microbial Exploration, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Mathias Leblanc
- Animal Resources Department, Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Sean C Adams
- Animal Resources Department, Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Christopher A Lowry
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Microbial Exploration, University of Colorado Boulder, Boulder, CO 80309, USA; Department of Physical Medicine & Rehabilitation and Center for Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Rocky Mountain Regional Veterans Affairs Medical Center (RMRVAMC), Aurora, CO 80045, USA; Military and Veteran Microbiome: Consortium for Research and Education (MVM-CoRE), Aurora, CO 80045, USA.
| | - Jon D Reuter
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA; Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA; Office of Animal Resources, University of Colorado Boulder, Boulder, CO 80309, USA.
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Ganouna-Cohen G, Khadangi F, Marcouiller F, Bossé Y, Joseph V. Additive effects of orchiectomy and intermittent hypoxia on lung mechanics and inflammation in C57BL/6J male mice. Exp Physiol 2021; 107:68-81. [PMID: 34761830 DOI: 10.1113/ep090050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/05/2021] [Indexed: 01/01/2023]
Abstract
NEW FINDINGS What is the central question of this study? Does endogenous testosterone modulate the consequences of intermittent hypoxia (IH) in the lungs of male mice? What is the main finding and its importance? Orchiectomized mice exposed to IH develop a pattern that is similar to emphysema or obstructive lung disease with elevated lung volumes, low pulmonary elastance during a methacholine challenge test and high counts of lymphocytes in bronchoalveolar lavages. Since low testosterone levels and other respiratory diseases are common in sleep apnoea, there is a clear clinical relevance to these results. ABSTRACT We tested the hypothesis that low testosterone levels modulate the pulmonary responses to intermittent hypoxia (IH; used as a model of sleep apnoea (SA)) in male mice. We used intact (SHAM) or orchiectomized (ORX) mice exposed to IH for 14 days (12 h/day, 10 cycles/h, 6% oxygen) or to normoxia (Nx). We first measured ventilation and metabolic rates in freely behaving mice (whole-body plethysmography) and then respiratory mechanics in tracheotomized mice (flexiVent). We assessed the respiratory system resistance and elastance (Ers ), Newtonian resistance (resistance of the large airways), tissue damping and tissue elastance (H) under baseline conditions and during a methacholine challenge test. We also measured the quasi-static compliance and inspiratory capacity with partial pressure-volume loops. Finally, inflammatory cells were counted in the broncho-alveolar lavage (BAL) and we measured lung volume by water displacement. ORX-IH mice had higher tidal volume, inspiratory capacity and lung volume compared to the other groups, but showed signs of low efficiency of O2 exchange rate relative to minute ventilation. During the methacholine challenge, orchiectomy decreased the values of most mechanical parameters and IH reduced Ers and H leading to very low values in ORX-IH mice. Finally, the total number of cells and the number of lymphocytes in BAL were both increased by IH in ORX mice. Since reduced lung elasticity, low O2 extraction, increased lung volumes and inflammation are signs of emphysematous lung disease, we conclude that testosterone might prevent lung emphysema during IH exposures.
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Affiliation(s)
- Gauthier Ganouna-Cohen
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - Fatemeh Khadangi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - François Marcouiller
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - Ynuk Bossé
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
| | - Vincent Joseph
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie du Québec, Université Laval, Québec, QC, Canada
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Ulland TK, Ewald AC, Knutson AO, Marino KM, Smith SMC, Watters JJ. Alzheimer's Disease, Sleep Disordered Breathing, and Microglia: Puzzling out a Common Link. Cells 2021; 10:2907. [PMID: 34831129 PMCID: PMC8616348 DOI: 10.3390/cells10112907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 12/14/2022] Open
Abstract
Sleep Disordered Breathing (SDB) and Alzheimer's Disease (AD) are strongly associated clinically, but it is unknown if they are mechanistically associated. Here, we review data covering both the cellular and molecular responses in SDB and AD with an emphasis on the overlapping neuroimmune responses in both diseases. We extensively discuss the use of animal models of both diseases and their relative utilities in modeling human disease. Data presented here from mice exposed to intermittent hypoxia indicate that microglia become more activated following exposure to hypoxia. This also supports the idea that intermittent hypoxia can activate the neuroimmune system in a manner like that seen in AD. Finally, we highlight similarities in the cellular and neuroimmune responses between SDB and AD and propose that these similarities may lead to a pathological synergy between SDB and AD.
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Affiliation(s)
- Tyler K. Ulland
- Department of Pathology and Laboratory Medicine, University of Wisconsin Madison, Madison, WI 53705, USA; (T.K.U.); (K.M.M.)
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI 53705, USA
| | - Andrea C. Ewald
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
| | - Andrew O. Knutson
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
| | - Kaitlyn M. Marino
- Department of Pathology and Laboratory Medicine, University of Wisconsin Madison, Madison, WI 53705, USA; (T.K.U.); (K.M.M.)
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI 53705, USA
| | - Stephanie M. C. Smith
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
| | - Jyoti J. Watters
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI 53705, USA
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI 53706, USA; (A.C.E.); (A.O.K.); (S.M.C.S.)
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8
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Ivy CM, Prest H, West CM, Scott GR. Distinct Mechanisms Underlie Developmental Plasticity and Adult Acclimation of Thermogenic Capacity in High-Altitude Deer Mice. Front Physiol 2021; 12:718163. [PMID: 34456754 PMCID: PMC8385410 DOI: 10.3389/fphys.2021.718163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/08/2021] [Indexed: 11/13/2022] Open
Abstract
Developmental plasticity can elicit phenotypic adjustments that help organisms cope with environmental change, but the relationship between developmental plasticity and plasticity in adult life (e.g., acclimation) remains unresolved. We sought to examine developmental plasticity and adult acclimation in response to hypoxia of aerobic capacity (V̇O2max) for thermogenesis in deer mice (Peromyscus maniculatus) native to high altitude. Deer mice were bred in captivity and exposed to normoxia or one of four hypoxia treatments (12 kPa O2) across life stages: adult hypoxia (6–8 weeks), post-natal hypoxia (birth to adulthood), life-long hypoxia (before conception to adulthood), and parental hypoxia (mice conceived and raised in normoxia, but parents previously exposed to hypoxia). Hypoxia during perinatal development increased V̇O2max by a much greater magnitude than adult hypoxia. The amplified effect of developmental hypoxia resulted from physiological plasticity that did not occur with adult hypoxia – namely, increases in lung ventilation and volume. Evolved characteristics of deer mice enabled developmental plasticity, because white-footed mice (P. leucopus; a congener restricted to low altitudes) could not raise pups in hypoxia. Parental hypoxia had no persistent effects on V̇O2max. Therefore, developmental plasticity can have much stronger phenotypic effects and can manifest from distinct physiological mechanisms from adult acclimation.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Haley Prest
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Claire M West
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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9
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Drummond SE, Burns DP, O'Connor KM, Clarke G, O'Halloran KD. The role of NADPH oxidase in chronic intermittent hypoxia-induced respiratory plasticity in adult male mice. Respir Physiol Neurobiol 2021; 292:103713. [PMID: 34116239 DOI: 10.1016/j.resp.2021.103713] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/18/2021] [Accepted: 06/06/2021] [Indexed: 10/21/2022]
Abstract
Reactive oxygen species (ROS) are proposed as mediators of chronic intermittent hypoxia (CIH)-induced respiratory plasticity. We sought to determine if NADPH oxidase 2 (NOX2)-derived ROS underpin CIH-induced maladaptive changes in respiratory control. Adult male mice (C57BL/6 J) were assigned to one of three groups: normoxic controls (sham); chronic intermittent hypoxia-exposed (CIH, 12 cycles/hour, 8 h/day for 14 days); and CIH + apocynin (NOX2 inhibitor, 2 mM) given in the drinking water throughout exposure to CIH. In addition, we studied sham and CIH-exposed NOX2-null mice (B6.129S-CybbTM1Din/J). Whole-body plethysmography was used to measure breathing and metabolic parameters. Ventilation (V̇I/V̇CO2) during normoxia was unaffected by CIH, but apnoea index was increased, which was prevented by apocynin, but not by NOX2 deletion. The ventilatory response to hypercapnia following exposure to CIH was potentiated in NOX2-null mice. Our results reveal ROS-dependent influences on the control of breathing and point to antioxidant intervention as a potential adjunctive therapeutic strategy in respiratory control disorders.
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Affiliation(s)
- Sarah E Drummond
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - David P Burns
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Karen M O'Connor
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Gerard Clarke
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland.
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10
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Faber JE, Storz JF, Cheviron ZA, Zhang H. High-altitude rodents have abundant collaterals that protect against tissue injury after cerebral, coronary and peripheral artery occlusion. J Cereb Blood Flow Metab 2021; 41:731-744. [PMID: 32703056 PMCID: PMC7983333 DOI: 10.1177/0271678x20942609] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/03/2020] [Accepted: 06/22/2020] [Indexed: 12/22/2022]
Abstract
Collateral number/density varies widely in brain and other tissues among strains of Mus musculus mice due to differences in genetic background. Recent studies have shown that prolonged exposure to reduced atmospheric oxygen induces additional collaterals to form, suggesting that natural selection may favor increased collaterals in populations native to high-altitude. High-altitude guinea pigs (Cavia) and deer mice (Peromyscus) were compared with lowland species of Peromyscus, Mus and Rattus (9 species/strains examined). Collateral density, diameter and other morphometrics were measured in brain where, importantly, collateral abundance reflects that in other tissues of the same individual. Guinea pigs and high-altitude deer mice had a greater density of pial collaterals than lowlanders. Consistent with this, guinea pigs and highlander mice evidenced complete and 80% protection against stroke, respectively. They also sustained significantly less ischemia in heart and lower extremities after arterial occlusion. Vessels of the circle of Willis, including the communicating collateral arteries, also exhibited unique features in the highland species. Our findings support the hypothesis that species native to high-altitude have undergone genetic selection for abundant collaterals, suggesting that besides providing protection in obstructive disease, collaterals serve a physiological function to optimize oxygen delivery to meet oxygen demand when oxygen is limiting.
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Affiliation(s)
- James E Faber
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Hua Zhang
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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11
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Arias-Reyes C, Soliz J, Joseph V. Mice and Rats Display Different Ventilatory, Hematological, and Metabolic Features of Acclimatization to Hypoxia. Front Physiol 2021; 12:647822. [PMID: 33776799 PMCID: PMC7994900 DOI: 10.3389/fphys.2021.647822] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
Phylogeographic studies showed that house mice (Mus musculus) originated in the Himalayan region, while common rats (Rattus rattus and Rattus norvegicus) come from the lowlands of China and India. Accordingly, it has been proposed that its origins gave mice, but not rats, the ability to invade ecological niches at high altitudes (pre-adaptation). This proposal is strongly supported by the fact that house mice are distributed throughout the world, while common rats are practically absent above 2,500 m. Considering that the ability of mammals to colonize high-altitude environments (>2,500 m) is limited by their capability to tolerate reduced oxygen availability, in this work, we hypothesize that divergences in the ventilatory, hematological, and metabolic phenotypes of mice and rats establish during the process of acclimatization to hypoxia (Hx). To test this hypothesis male FVB mice and Sprague-Dawley (SD) rats were exposed to Hx (12% O2) for 0 h (normoxic controls), 6 h, 1, 7, and 21 days. We assessed changes in ventilatory [minute ventilation (VE), respiratory frequency (fR), and tidal volume (VT)], hematological (hematocrit and hemoglobin concentration), and metabolic [whole-body O2 consumption (VO2) and CO2 production (VCO2), and liver mitochondrial oxygen consumption rate (OCR) parameters]. Compared to rats, results in mice show increased ventilatory, metabolic, and mitochondrial response. In contrast, rats showed quicker and higher hematological response than mice and only minor ventilatory and metabolic adjustments. Our findings may explain, at least in part, why mice, but not rats, were able to colonize high-altitude habitats.
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Affiliation(s)
- Christian Arias-Reyes
- Centre de Recherche de l'Institute Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Jorge Soliz
- Centre de Recherche de l'Institute Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Vincent Joseph
- Centre de Recherche de l'Institute Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
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12
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Chrobok L, Wojcik M, Klich JD, Pradel K, Lewandowski MH, Piggins HD. Phasic Neuronal Firing in the Rodent Nucleus of the Solitary Tract ex vivo. Front Physiol 2021; 12:638695. [PMID: 33762969 PMCID: PMC7982836 DOI: 10.3389/fphys.2021.638695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/10/2021] [Indexed: 02/02/2023] Open
Abstract
Phasic pattern of neuronal activity has been previously described in detail for magnocellular vasopressin neurons in the hypothalamic paraventricular and supraoptic nuclei. This characteristic bistable pattern consists of alternating periods of electrical silence and elevated neuronal firing, implicated in neuropeptide release. Here, with the use of multi-electrode array recordings ex vivo, we aimed to study the firing pattern of neurons in the nucleus of the solitary tract (NTS) - the brainstem hub for homeostatic, cardio-vascular, and metabolic processes. Our recordings from the mouse and rat hindbrain slices reveal the phasic activity pattern to be displayed by a subset of neurons in the dorsomedial NTS subjacent to the area postrema (AP), with the inter-spike interval distribution closely resembling that reported for phasic magnocellular vasopressin cells. Additionally, we provide interspecies comparison, showing higher phasic frequency and firing rate of phasic NTS cells in mice compared to rats. Further, we describe daily changes in their firing rate and pattern, peaking at the middle of the night. Last, we reveal these phasic cells to be sensitive to α 2 adrenergic receptors activation and to respond to electrical stimulation of the AP. This study provides a comprehensive description of the phasic neuronal activity in the rodent NTS and identifies it as a potential downstream target of the AP noradrenergic system.
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Affiliation(s)
- Lukasz Chrobok
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland.,Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Michal Wojcik
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Jasmin Daniela Klich
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Kamil Pradel
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Marian Henryk Lewandowski
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Hugh David Piggins
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,School of Physiology, Pharmacology, and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
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13
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Javrushyan H, Avtandilyan N, Trchounian A. The effects of NO on the urea cycle pathway in short-term intermittent hypobaric hypoxia in rats. Respir Physiol Neurobiol 2020; 285:103598. [PMID: 33326865 DOI: 10.1016/j.resp.2020.103598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/09/2022]
Abstract
Short-term hypoxic states can influence the health and life activities of lowlanders who travel shortly to high altitudes, in transitory situations, such as surgical ischemia-reperfusion (to one or several organs), and in some sporting activities, such as parachuting and extreme skiing, mountain rescue teams, regular commercial flight crews, in which the subject may not even notice the hypoxia. NO is an integral part of the human physiological response to hypoxia. Until recently, the urea cycle (UC) was only considered as an important mechanism for neutralizing ammonia. We are the first to reveal an interrelation in hypoxic states between the activities of NO-synthase and UC enzymes in male rats' liver, kidney and brain. In the presented work, we have shown that during short-term intermittent hypobaric hypoxia (IHH) all enzymes of UC play an important role in the maintenance of NO quantity. The results allow thinking that kidney and brain argininosuccinate synthase (ASS) and argininosuccinate lyase (ASL) and liver ASS and ASL can be different isoenzymes. It is worth mentioning that the results have revealed new sides of l-arginine metabolism in a hypoxic state in male rats.
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Affiliation(s)
- Hayarpi Javrushyan
- Laboratory of Biochemistry, Research Institute of Biology, Yerevan State University, Yerevan, Armenia.
| | - Nikolay Avtandilyan
- Laboratory of Biochemistry, Research Institute of Biology, Yerevan State University, Yerevan, Armenia; Department of Biochemistry, Microbiology and Biotechnology, Yerevan State University, Yerevan, Armenia.
| | - Armen Trchounian
- Department of Biochemistry, Microbiology and Biotechnology, Yerevan State University, Yerevan, Armenia.
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14
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Kastner N, Zlabinger K, Spannbauer A, Traxler D, Mester-Tonczar J, Hašimbegović E, Gyöngyösi M. New Insights and Current Approaches in Cardiac Hypertrophy Cell Culture, Tissue Engineering Models, and Novel Pathways Involving Non-Coding RNA. Front Pharmacol 2020; 11:1314. [PMID: 32973530 PMCID: PMC7472597 DOI: 10.3389/fphar.2020.01314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 08/07/2020] [Indexed: 12/23/2022] Open
Abstract
Cardiac hypertrophy is an ongoing clinical challenge, as risk factors such as obesity, smoking and increasing age become more widespread, which lead to an increasing prevalence of developing hypertrophy. Pathological hypertrophy is a maladaptive response to stress conditions, such as pressure overload, and involve a number of changes in cellular mechanisms, gene expression and pathway regulations. Although several important pathways involved in the remodeling and hypertrophy process have been identified, further research is needed to achieve a better understanding and explore new and better treatment options. More recently discovered pathways showed the involvement of several non-coding RNAs, including micro RNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), which either promote or inhibit the remodeling process and pose a possible target for novel therapy approaches. In vitro modeling serves as a vital tool for this further pathway analysis and treatment testing and has vastly improved over the recent years, providing a less costly and labor-intensive alternative to in vivo animal models.
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Affiliation(s)
- Nina Kastner
- Department of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Katrin Zlabinger
- Department of Cardiology, Medical University of Vienna, Vienna, Austria
| | | | - Denise Traxler
- Department of Cardiology, Medical University of Vienna, Vienna, Austria
| | | | - Ena Hašimbegović
- Department of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Mariann Gyöngyösi
- Department of Cardiology, Medical University of Vienna, Vienna, Austria
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15
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Rood K, Lopez V, La Frano MR, Fiehn O, Zhang L, Blood AB, Wilson SM. Gestational Hypoxia and Programing of Lung Metabolism. Front Physiol 2019; 10:1453. [PMID: 31849704 PMCID: PMC6895135 DOI: 10.3389/fphys.2019.01453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Gestational hypoxia is a risk factor in the development of pulmonary hypertension in the newborn and other sequela, however, the mechanisms associated with the disease remain poorly understood. This review highlights disruption of metabolism by antenatal high altitude hypoxia and the impact this has on pulmonary hypertension in the newborn with discussion of model organisms and human populations. There is particular emphasis on modifications in glucose and lipid metabolism along with alterations in mitochondrial function. Additional focus is placed on increases in oxidative stress and the progression of pulmonary vascular disease in the newborn and on the need for further exploration using a combination of contemporary and classical approaches.
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Affiliation(s)
- Kristiana Rood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Vanessa Lopez
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Michael R La Frano
- Department of Food Science and Nutrition, Center for Health Research, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Health Research, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Oliver Fiehn
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA, United States.,Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| | - Lubo Zhang
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Arlin B Blood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Sean M Wilson
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
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16
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Wang Y, Lee MYK, Mak JCW, Ip MSM. Low-Frequency Intermittent Hypoxia Suppresses Subcutaneous Adipogenesis and Induces Macrophage Polarization in Lean Mice. Diabetes Metab J 2019; 43:659-674. [PMID: 31237128 PMCID: PMC6834831 DOI: 10.4093/dmj.2018.0196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/06/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The relationship between obstructive sleep apnoea (OSA) and metabolic disorders is complex and highly associated. The impairment of adipogenic capacity in pre-adipocytes may promote adipocyte hypertrophy and increase the risk of further metabolic dysfunction. We hypothesize that intermittent hypoxia (IH), as a pathophysiologic feature of OSA, may regulate adipogenesis by promoting macrophage polarization. METHODS Male C57BL/6N mice were exposed to either IH (240 seconds of 10% O₂ followed by 120 seconds of 21% O₂, i.e., 10 cycles/hour) or intermittent normoxia (IN) for 6 weeks. Stromal-vascular fractions derived from subcutaneous (SUB-SVF) and visceral (VIS-SVF) adipose tissues were cultured and differentiated. Conditioned media from cultured RAW 264.7 macrophages after air (Raw) or IH exposure (Raw-IH) were incubated with SUB-SVF during adipogenic differentiation. RESULTS Adipogenic differentiation of SUB-SVF but not VIS-SVF from IH-exposed mice was significantly downregulated in comparison with that derived from IN-exposed mice. IH-exposed mice compared to IN-exposed mice showed induction of hypertrophic adipocytes and increased preferential infiltration of M1 macrophages in subcutaneous adipose tissue (SAT) compared to visceral adipose tissue. Complementary in vitro analysis demonstrated that Raw-IH media significantly enhanced inhibition of adipogenesis of SUB-SVF compared to Raw media, in agreement with corresponding gene expression levels of differentiation-associated markers and adipogenic transcription factors. CONCLUSION Low frequency IH exposure impaired adipogenesis of SAT in lean mice, and macrophage polarization may be a potential mechanism for the impaired adipogenesis.
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Affiliation(s)
- Yan Wang
- Department of Medicine, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
- Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China
| | - Mary Yuk Kwan Lee
- Department of Medicine, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
| | - Judith Choi Wo Mak
- Department of Medicine, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
- Department of Pharmacology & Pharmacy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
| | - Mary Sau Man Ip
- Department of Medicine, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong.
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17
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Klawitter J, Klawitter J, Pennington A, Kirkpatrick B, Roda G, Kotecha NC, Thurman JM, Christians U. Cyclophilin D knockout protects the mouse kidney against cyclosporin A-induced oxidative stress. Am J Physiol Renal Physiol 2019; 317:F683-F694. [PMID: 31188033 DOI: 10.1152/ajprenal.00417.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial dysfunction and oxidative stress have been implicated in cyclosporin A (CsA)-induced nephrotoxicity. CsA interacts with cyclophilin D (CypD), an essential component of the mitochondrial permeability transition pore and regulator of cell death processes. Controversial reports have suggested that CypD deletion may or may not protect cells against oxidative stress-induced cell death. In the present study, we treated wild-type (WT) mice and mice lacking CypD [peptidylprolyl isomerase F knockout (Ppif-/-) mice] with CsA to test the role and contribution of CypD to the widely described CsA-induced renal toxicity and oxidative stress. Our results showed an increase in the levels of several known uremic toxins as well as the oxidative stress markers PGF2α and 8-isoprostane in CsA-treated WT animals but not in Ppif-/- animals. Similarly, a decline in S-adenosylmethionine and the resulting methylation potential indicative of DNA hypomethylation were observed only in CsA-treated WT mice. This confirms previous reports of the protective effects of CypD deletion on the mouse kidney mediated through a stronger resistance of these animals to oxidative stress and DNA methylation damage. However, a negative effect of CsA on the glycolysis and overall energy metabolism in Ppif-/- mice also indicated that additional, CypD-parallel pathways are involved in the toxic effects of CsA on the kidney. In summary, CsA-mediated induction of oxidative stress is associated with CypD, with CypD deletion providing a protective effect, whereas the reduction of energy production observed upon CsA exposure did not depend on the animals' CypD status.
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Affiliation(s)
- Jelena Klawitter
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
- Division of Nephrology and Hypertension, Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Jost Klawitter
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Alexander Pennington
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Bruce Kirkpatrick
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Galen Roda
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Nidhi C Kotecha
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
| | - Joshua M Thurman
- Division of Nephrology and Hypertension, Department of Medicine, University of Colorado Denver, Aurora, Colorado
| | - Uwe Christians
- Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, Aurora, Colorado
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18
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Kouyoumdjian L, Gangloff EJ, Souchet J, Cordero GA, Dupoué A, Aubret F. Transplanting gravid lizards to high elevation alters maternal and embryonic oxygen physiology, but not reproductive success or hatchling phenotype. J Exp Biol 2019; 222:jeb.206839. [DOI: 10.1242/jeb.206839] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 06/19/2019] [Indexed: 12/13/2022]
Abstract
Increased global temperatures have opened previously inhospitable habitats, such as at higher elevations. However, the reduction of oxygen partial pressure with increase in elevation represents an important physiological constraint that may limit colonization of such habitats, even if the thermal niche is appropriate. To test the mechanisms underlying the response to ecologically-relevant levels of hypoxia, we performed a translocation experiment with the common wall lizard (Podarcis muralis), a widespread European lizard amenable to establishing populations outside its natural range. We investigated the impacts of hypoxia on the oxygen physiology and reproductive output of gravid common wall lizards and the subsequent development and morphology of their offspring. Lowland females transplanted to high elevations increased their haematocrit and haemoglobin concentration within days and maintained routine metabolism compared to lizards kept at native elevations. However, transplanted lizards suffered from increased reactive oxygen metabolite production near the oviposition date, suggesting a cost of reproduction at high elevation. Transplanted females and females native to different elevations did not differ in reproductive output (clutch size, egg mass, relative clutch mass, or embryonic stage at oviposition) or in post-oviposition body condition. Developing embryos reduced heart rates and prolonged incubation times at high elevations within the native range and at extreme high elevations beyond the current range, but this reduced oxygen availability did not affect metabolic rate, hatching success, or hatchling size. These results suggest that this opportunistic colonizer is capable of successfully responding to novel environmental constraints in these important life-history stages.
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Affiliation(s)
- Laura Kouyoumdjian
- Station d'Ecologie Théorique et Expérimentale du CNRS – UMR 5321, Moulis, France
| | - Eric J. Gangloff
- Station d'Ecologie Théorique et Expérimentale du CNRS – UMR 5321, Moulis, France
| | - Jérémie Souchet
- Station d'Ecologie Théorique et Expérimentale du CNRS – UMR 5321, Moulis, France
| | - Gerardo A. Cordero
- Fachbereich Geowissenschaften, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Andréaz Dupoué
- CNRS UPMC, UMR 7618, iEES Paris, Université Pierre et Marie Curie, Paris, France
| | - Fabien Aubret
- Station d'Ecologie Théorique et Expérimentale du CNRS – UMR 5321, Moulis, France
- School of Molecular and Life Sciences, Curtin University, 6102 WA, Australia
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19
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Suzuki TA, Martins FM, Nachman MW. Altitudinal variation of the gut microbiota in wild house mice. Mol Ecol 2018; 28:2378-2390. [PMID: 30346069 DOI: 10.1111/mec.14905] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/25/2018] [Accepted: 10/06/2018] [Indexed: 12/11/2022]
Abstract
The maintenance of oxygen homeostasis in the gut is critical for the maintenance of a healthy gut microbiota. However, few studies have explored how the concentration of atmospheric oxygen affects the gut microbiota in natural populations. High-altitude environments provide an opportunity to study the potential effects of atmospheric oxygen on the composition and function of the gut microbiota. Here, we characterized the caecal microbial communities of wild house mice (Mus musculus domesticus) in two independent altitudinal transects, one in Ecuador and one in Bolivia, from sea level to nearly 4,000 m. First, we found that differences in altitude were associated with differences in the gut microbial community after controlling for the effects of body mass, diet, reproductive status and population of origin. Second, obligate anaerobes tended to show a positive correlation with altitude, while all other microbes tended to show a negative correlation with altitude. These patterns were seen independently in both transects, consistent with the expected effects of atmospheric oxygen on gut microbes. Prevotella was the most-enriched genus at high elevations in both transects, consistent with observations in high-altitude populations of pikas, ruminants and humans, and also consistent with observations of laboratory mice exposed to hypoxic conditions. Lastly, the renin-angiotensin system, a recently proposed microbiota-mediated pathway of blood pressure regulation, was the top predicted metagenomic pathway enriched in high altitudes in both transects. These results suggest that high-altitude environments affect the composition and function of the gut microbiota in wild mammals.
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Affiliation(s)
- Taichi A Suzuki
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, California
| | - Felipe M Martins
- Department of Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Michael W Nachman
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, California
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20
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Jochmans-Lemoine A, Revollo S, Villalpando G, Valverde I, Gonzales M, Laouafa S, Soliz J, Joseph V. Divergent Mitochondrial Antioxidant Activities and Lung Alveolar Architecture in the Lungs of Rats and Mice at High Altitude. Front Physiol 2018; 9:311. [PMID: 29670534 PMCID: PMC5893716 DOI: 10.3389/fphys.2018.00311] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/14/2018] [Indexed: 01/22/2023] Open
Abstract
Compared with mice, adult rats living at 3,600 m above sea level (SL—La Paz, Bolivia) have high hematocrit, signs of pulmonary hypertension, and low lung volume with reduced alveolar surface area. This phenotype is associated with chronic mountain sickness in humans living at high altitude (HA). We tested the hypothesis that this phenotype is associated with impaired gas exchange and oxidative stress in the lungs. We used rats and mice (3 months old) living at HA (La Paz) and SL (Quebec City, Canada) to measure arterial oxygen saturation under graded levels of hypoxia (by pulse oximetry), the alveolar surface area in lung slices and the activity of pro- (NADPH and xanthine oxidases—NOX and XO) and anti- (superoxide dismutase, and glutathione peroxidase—SOD and GPx) oxidant enzymes in cytosolic and mitochondrial lung protein extracts. HA rats have a lower arterial oxygen saturation and reduced alveolar surface area compared to HA mice and SL rats. Enzymatic activities (NOX, XO, SOD, and GPx) in the cytosol were similar between HA and SL animals, but SOD and GPx activities in the mitochondria were 2–3 times higher in HA vs. SL rats, and only marginally higher in HA mice vs. SL mice. Furthermore, the maximum activity of cytochrome oxidase-c (COX) measured in mitochondrial lung extracts was also 2 times higher in HA rats compared with SL rats, while there was only a small increase in HA mice vs. SL mice. Interestingly, compared with SL controls, alterations in lung morphology are not observed for young rats at HA (15 days after birth), and enzymatic activities are only slightly altered. These results suggest that rats living at HA have a gradual reduction of their alveolar surface area beyond the postnatal period. We can speculate that the elevation of SOD, GPx, and COX activities in the lung mitochondria are not sufficient to compensate for oxidative stress, leading to damage of the lung tissue in rats.
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Affiliation(s)
- Alexandra Jochmans-Lemoine
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada
| | - Susana Revollo
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada
| | - Gabriella Villalpando
- Instituto Boliviano de Biologia de Altura, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Ibana Valverde
- Instituto Boliviano de Biologia de Altura, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Marcelino Gonzales
- Instituto Boliviano de Biologia de Altura, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Sofien Laouafa
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada.,Centre National de la Recherche Scientifique, UMR 5023, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Jorge Soliz
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada
| | - Vincent Joseph
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada
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Roberts SM, Rohr AC, Mikheev VB, Munson J, Sabo-Attwood T. Influence of airborne particulates on respiratory tract deposition of inhaled toluene and naphthalene in the rat. Inhal Toxicol 2018; 30:19-28. [PMID: 29465005 DOI: 10.1080/08958378.2018.1438539] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Most studies report that inhaled volatile and semivolatile organic compounds (VOCs/SVOCs) tend to deposit in the upper respiratory tract, while ultrafine (or near ultrafine) particulate matter (PM) (∼100 nm) reaches the lower airways. The objective of this study was to determine whether carbon particle co-exposure carries VOCs/SVOCs deeper into the lungs where they are deposited. MATERIALS AND METHODS Male Sprague-Dawley rats were exposed by inhalation (nose-only) to radiolabeled toluene (20 ppm) or naphthalene (20 ppm) on a single occasion for 1 h, with or without concurrent carbon particle exposure (∼5 mg/m3). The distribution of radiolabel deposited within the respiratory tract of each animal was determined after sacrifice. The extent of adsorption of toluene and naphthalene to airborne carbon particles under the exposure conditions of the study was also assessed. RESULTS We found that in the absence of particles, the highest deposition of both naphthalene and toluene was observed in the upper respiratory tract. Co-exposure with carbon particles tended to increase naphthalene deposition slightly throughout the respiratory tract, whereas slight decreases in toluene deposition were observed. Few differences were statistically significant. Naphthalene showed greater adsorption to the particles compared to toluene, but overall the particle-adsorbed concentration of each of these compounds was a small fraction of the total inspired concentration. CONCLUSIONS These studies imply that at the concentrations used for the exposures in this study, inhaled carbon particles do not substantially alter the deposition of naphthalene and toluene within the respiratory tract.
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Affiliation(s)
- Stephen M Roberts
- a Center for Environmental & Human Toxicology , University of Florida , Gainesville , FL , USA
| | - Annette C Rohr
- b Electric Power Research Institute , Palo Alto , CA , USA
| | - Vladimir B Mikheev
- c Battelle Public Health Center for Tobacco Research , Columbus , OH , USA
| | - John Munson
- a Center for Environmental & Human Toxicology , University of Florida , Gainesville , FL , USA
| | - Tara Sabo-Attwood
- d Department of Environmental and Global Health , University of Florida , Gainesville , FL , USA
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Spiacci A, Vilela-Costa HH, Sant'Ana AB, Fernandes GG, Frias AT, da Silva GSF, Antunes-Rodrigues J, Zangrossi H. Panic-like escape response elicited in mice by exposure to CO 2, but not hypoxia. Prog Neuropsychopharmacol Biol Psychiatry 2018; 81:178-186. [PMID: 29111406 DOI: 10.1016/j.pnpbp.2017.10.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/18/2017] [Accepted: 10/23/2017] [Indexed: 10/18/2022]
Abstract
Exposure to elevated concentrations of CO2 or hypoxia has been widely used in psychiatric research as a panic provoking stimulus. However, the use of these respiratory challenges to model panic-like responses in experimental animals has been less straightforward. Little data is available, from behavioral and endocrine perspectives, to support the conclusion that a marked aversive situation, such as that experienced during panic attacks, was evoked in these animals. We here compared the behavioral responses of male CB57BL/6 mice during exposure to 20% CO2 or 7% O2 and its consequence on plasma levels of corticosterone. We also evaluated whether clinically-effective panicolytic drugs affect the behavioral responses expressed during CO2 exposure. The results showed that whereas hypoxia caused a marked reduction in locomotion, inhalation of CO2-enriched air evoked an active escape response, characterized by bouts of upward leaps directed to the border of the experimental cage, interpreted as escape attempts. Corticosterone levels were increased 30min after either of the respiratory challenges used, but it was higher in the hypoxia group. Chronic (21days), but not acute, treatment with fluoxetine or imipramine (5, 10 or 15mg/kg) or a single injection of alprazolam (0.025, 0.05 or 0.1mg/kg), but not of the anxiolytic diazepam (0.025, 0.05 or 0.1 and 1mg/kg) reduced the number of escape attempts, indicating a panicolytic-like effect. Altogether, the results suggest that whereas hypoxia increased anxiety, exposure to 20% CO2 evoked a panic-like state. The latter condition/test protocol seems to be a simple and validated model for studying in mice pathophysiological mechanisms and the screening of novel drugs for panic disorder.
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Affiliation(s)
- Ailton Spiacci
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil.
| | - Heloisa H Vilela-Costa
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil
| | - Ana Beatriz Sant'Ana
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil
| | - Gabriel Gripp Fernandes
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil
| | - Alana Tercino Frias
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil
| | | | - José Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirao Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Hélio Zangrossi
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil.
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23
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Tenorio‐Lopes L, Baldy C, Jochmans‐Lemoine A, Mercier O, Pothier‐Piccinin O, Seaborn T, Joseph V, Marc I, Kinkead R. Consequences of maternal omega-3 polyunsaturated fatty acid supplementation on respiratory function in rat pups. J Physiol 2017; 595:1637-1655. [PMID: 27861919 PMCID: PMC6426158 DOI: 10.1113/jp273471] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/04/2016] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS Incomplete development of the neural circuits that control breathing contributes to respiratory disorders in pre-term infants. Manifestations include respiratory instability, prolonged apnoeas and poor ventilatory responses to stimuli. Based on evidence suggesting that omega-3 polyunsaturated fatty acids (n-3 PUFA) improves brain development, we determined whether n-3 PUFA supplementation (via the maternal diet) improves respiratory function in 10-11-day-old rat pups. n-3 PUFA treatment prolonged apnoea duration but augmented the relative pulmonary surface area and the ventilatory response to hypoxia. During hypoxia, the drop in body temperature measured in treated pups was 1 °C less than in controls. n-3 PUFA treatment also reduced microglia cell density in the brainstem. Although heterogeneous, the results obtained in rat pups constitute a proof of concept that n-3 PUFA supplementation can have positive effects on neonatal respiration. This includes a more sustained hypoxic ventilatory response and a decreased respiratory inhibition during laryngeal chemoreflex. ABSTRACT Most pre-term infants present respiratory instabilities and apnoeas as a result of incomplete development of the neural circuits that control breathing. Because omega-3 polyunsaturated fatty acids (n-3 PUFA) benefit brain development, we hypothesized that n-3 PUFA supplementation (via the maternal diet) improves respiratory function in rat pups. Pups received n-3 PUFA supplementation from an enriched diet (13 g kg-1 of n-3 PUFA) administered to the mother from birth until the experiments were performed (postnatal days 10-11). Controls received a standard diet (0.3 g kg-1 of n-3 PUFA). Breathing was measured in intact pups at rest and during hypoxia (FiO2 = 0.12; 20 min) using whole body plethysmography. The duration of apnoeas induced by stimulating the laryngeal chemoreflex (LCR) was measured under anaesthesia. Lung morphology was compared between groups. Maternal n-3 PUFA supplementation effectively raised n-3 PUFA levels above control levels both in the blood and brainstem of pups. In intact, resting pups, n-3 PUFA increased the frequency and duration of apnoeas, especially in females. During hypoxia, n-3 PUFA supplemented pups hyperventilated 23% more than controls; their anapyrexic response was 1 °C less than controls. In anaesthetized pups, n-3 PUFA shortened the duration of LCR-induced apnoeas by 32%. The relative pulmonary surface area of n-3 PUFA supplemented pups was 12% higher than controls. Although n-3 PUFA supplementation augments apnoeas, there is no clear evidence of deleterious consequences on these pups. Based on the improved lung architecture and responses to respiratory challenges, this neonatal treatment appears to be beneficial to the offspring. However, further experiments are necessary to establish its overall safety.
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Affiliation(s)
- Luana Tenorio‐Lopes
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
| | - Cécile Baldy
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
| | | | - Océane Mercier
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
| | | | - Tommy Seaborn
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
| | - Vincent Joseph
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
| | - Isabelle Marc
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
| | - Richard Kinkead
- Department of Pediatrics, Université LavalCentre de Recherche du CHU de QuébecQuébecQCCanada
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Ivy CM, Scott GR. Ventilatory acclimatization to hypoxia in mice: Methodological considerations. Respir Physiol Neurobiol 2016; 235:95-103. [PMID: 27989891 DOI: 10.1016/j.resp.2016.10.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/30/2016] [Accepted: 10/27/2016] [Indexed: 01/15/2023]
Abstract
We examined ventilatory acclimatization to hypoxia (VAH) in CD1 mice, and contrasted results obtained using the barometric method on unrestrained mice with pneumotachography and pulse oximetry on restrained mice. Responses to progressive step reductions in O2 fraction (21%-8%) were assessed in mice acclimated to normoxia and hypobaric hypoxia (barometric pressure of 60kPa for 6-8 weeks). Hypoxia acclimation increased the hypoxic ventilatory response (primarily by increasing breathing frequency rather than tidal volume), arterial O2 saturation (SaO2) and heart rate in deep hypoxia, hypoxic chemosensitivity (ventilatory O2/CO2 equivalents versus SaO2), and respiratory water loss, and it blunted the hypoxic depression of metabolism and body temperature. Although some effects of hypoxia acclimation were qualitatively similar between methods, the effects were often greater in magnitude when assessed using pneumotachography. Furthermore, whereas hypoxia acclimation reduced ventilatory O2 equivalent and increased pulmonary O2 extraction in barometric experiments, it had the opposite effects in pneumotachography experiments. Our findings highlight the importance of considering the impact of how breathing is measured on the apparent responses to hypoxia.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada.
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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25
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Morgan BJ, Adrian R, Wang ZY, Bates ML, Dopp JM. Chronic intermittent hypoxia alters ventilatory and metabolic responses to acute hypoxia in rats. J Appl Physiol (1985) 2016; 120:1186-95. [PMID: 26917692 DOI: 10.1152/japplphysiol.00015.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 02/22/2016] [Indexed: 12/18/2022] Open
Abstract
We determined the effects of chronic exposure to intermittent hypoxia (CIH) on chemoreflex control of ventilation in conscious animals. Adult male Sprague-Dawley rats were exposed to CIH [nadir oxygen saturation (SpO2), 75%; 15 events/h; 10 h/day] or normoxia (NORM) for 21 days. We assessed the following responses to acute, graded hypoxia before and after exposures: ventilation (V̇e, via barometric plethysmography), V̇o2 and V̇co2 (analysis of expired air), heart rate (HR), and SpO2 (pulse oximetry via neck collar). We quantified hypoxia-induced chemoreceptor sensitivity by calculating the stimulus-response relationship between SpO2 and the ventilatory equivalent for V̇co2 (linear regression). An additional aim was to determine whether CIH causes proliferation of carotid body glomus cells (using bromodeoxyuridine). CIH exposure increased the slope of the V̇e/V̇co2/SpO2 relationship and caused hyperventilation in normoxia. Bromodeoxyuridine staining was comparable in CIH and NORM. Thus our CIH paradigm augmented hypoxic chemosensitivity without causing glomus cell proliferation.
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Affiliation(s)
- Barbara J Morgan
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin;
| | - Russell Adrian
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Zun-Yi Wang
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin
| | - Melissa L Bates
- Department of Health and Human Physiology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa; and
| | - John M Dopp
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin
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26
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Jochmans-Lemoine A, Shahare M, Soliz J, Joseph V. HIF1α and physiological responses to hypoxia are correlated in mice but not in rats. J Exp Biol 2016; 219:3952-3961. [DOI: 10.1242/jeb.142869] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/06/2016] [Indexed: 01/06/2023]
Abstract
We previously reported that rats and mice that have been raised for more than 30 generations in La Paz, Bolivia (3600m), display divergent physiological responses to high altitude (HA), including improved respiratory and metabolic control in mice. In the present study we asked whether these traits would also be present in response to hypoxia at sea level (SL). To answer this question, we exposed rats (SD) and mice (FVB) to normoxia (21% O2) or hypoxia (15 and 12% O2) for 6 hours and measured ventilation and metabolic rate (whole body plethysmography), and expression of the transcription factor HIF-1α (ELISA and Mass Spectrometry) and other proteins whose expression are regulated by hypoxia (Glucose Transporter 1, Pyruvate Dehydrogenase Kinase 1, and Angiopoietin 2 - Mass Spectrometry) in the brainstem. In response to hypoxia, compared with rats, mice had higher minute ventilation, lower metabolic rate, and higher expression of HIF-1α in the brainstem. In mice the expression level of HIF-1α was positively correlated with ventilation and negatively correlated with metabolic rate. In rats, the concentration of brainstem cytosolic protein decreased by 38% at 12% O2, while expression of the glucose transporter 1 increased. We conclude that mice and rats raised at sea level have divergent physiological and molecular responses to hypoxia, supporting the hypothesis that mice have innate traits that favor adaptation to altitude.
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Affiliation(s)
- Alexandra Jochmans-Lemoine
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Manju Shahare
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Jorge Soliz
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Vincent Joseph
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
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