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Manley GA, Maat B, Begall S, Malkemper P, Caspar KR, Moritz L, van Dijk P. Otoacoustic emissions in African mole-rats. Hear Res 2024; 445:108994. [PMID: 38520899 DOI: 10.1016/j.heares.2024.108994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
African mole-rats display highly derived hearing that is characterized by low sensitivity and a narrow auditory range restricted to low frequencies < 10 kHz. Recently, it has been suggested that two species of these rodents do not exhibit distortion product otoacoustic emissions (DPOAE), which was interpreted as evidence for a lack of cochlear amplification. If true, this would make them unique among mammals. However, both theoretical considerations on the generation of DPOAE as well as previously published experimental evidence challenge this assumption. We measured DPOAE and stimulus-frequency otoacoustic emissions (SFOAE) in three species of African mole-rats (Ansell's mole-rat - Fukomys anselli; Mashona mole-rat - Fukomys darlingi; naked mole-rat - Heterocephalus glaber) and found unexceptional otoacoustic emission values. Measurements were complicated by the remarkably long, narrow and curved external ear canals of these animals, for which we provide a morphological description. Both DPOAE and SFOAE displayed the highest amplitudes near 1 kHz, which corresponds to the region of best hearing in all tested species, as well as to the frequency region of the low-frequency acoustic fovea previously described in Ansell's mole-rat. Thus, the cochlea in African mole-rats shares the ability to generate evoked otoacoustic emission with other mammals.
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Affiliation(s)
- Geoffrey A Manley
- Department of Neuroscience, Faculty of Medicine, and Cluster of Excellence "Hearing for All", University of Oldenburg, 26129 Oldenburg, Germany.
| | - Bert Maat
- University of Groningen, University Medical Center Groningen, Department of Otorhinolaryngology/Head and Neck Surgery, Groningen, The Netherlands
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Essen, Germany
| | - Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior - caesar, Bonn, Germany
| | - Kai R Caspar
- Department of General Zoology, University of Duisburg-Essen, Essen, Germany; Institute for Cell Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Leif Moritz
- Max Planck Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior - caesar, Bonn, Germany
| | - Pim van Dijk
- University of Groningen, University Medical Center Groningen, Department of Otorhinolaryngology/Head and Neck Surgery, Groningen, The Netherlands
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2
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Gerhardt P, Begall S, Frädrich C, Renko K, Heinrich A, Köhrle J, Henning Y. Low thyroxine serves as an upstream regulator of ecophysiological adaptations in Ansell's mole-rats. Front Endocrinol (Lausanne) 2024; 15:1329083. [PMID: 38567302 PMCID: PMC10985354 DOI: 10.3389/fendo.2024.1329083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction About 10% of all rodent species have evolved a subterranean way of life, although life in subterranean burrows is associated with harsh environmental conditions that would be lethal to most animals living above ground. Two key adaptations for survival in subterranean habitats are low resting metabolic rate (RMR) and core body temperature (Tb). However, the upstream regulation of these traits was unknown thus far. Previously, we have reported exceptionally low concentrations of the thyroid hormone (TH) thyroxine (T4), and peculiarities in TH regulating mechanisms in two African mole-rat species, the naked mole-rat and the Ansell's mole-rat. Methods In the present study, we treated Ansell's mole-rats with T4 for four weeks and analyzed treatment effects on the tissue and whole organism level with focus on metabolism and thermoregulation. Results We found RMR to be upregulated by T4 treatment but not to the extent that was expected based on serum T4 concentrations. Our data point towards an extraordinary capability of Ansell's mole-rats to effectively downregulate TH signaling at tissue level despite very high serum TH concentrations, which most likely explains the observed effects on RMR. On the other hand, body weight was decreased in T4-treated animals and Tb was upregulated by T4 treatment. Moreover, we found indications of the hypothalamus-pituitary-adrenal axis potentially influencing the treatment effects. Conclusion Taken together, we provide the first experimental evidence that the low serum T4 concentrations of Ansell's mole-rats serve as an upstream regulator of low RMR and Tb. Thus, our study contributes to a better understanding of the ecophysiological evolution of the subterranean lifestyle in African mole-rats.
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Affiliation(s)
- Patricia Gerhardt
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Caroline Frädrich
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institut für Experimentelle Endokrinologie, Berlin, Germany
| | - Kostja Renko
- German Federal Institute for Risk Assessment, German Centre for the Protection of Laboratory Animals (Bf3R), Berlin, Germany
| | - Alexandra Heinrich
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Josef Köhrle
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institut für Experimentelle Endokrinologie, Berlin, Germany
| | - Yoshiyuki Henning
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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Henning Y, Adam K, Gerhardt P, Begall S. Hypoxic and hypercapnic burrow conditions lead to downregulation of free triiodothyronine and hematocrit in Ansell's mole-rats (Fukomys anselli). J Comp Physiol B 2024; 194:33-40. [PMID: 38059996 PMCID: PMC10940439 DOI: 10.1007/s00360-023-01526-0] [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: 09/04/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 12/08/2023]
Abstract
African mole-rats live in self-dug burrow systems under hypoxic and hypercapnic conditions. Adaptations to hypoxia include suppression of resting metabolic rate (RMR) and core body temperature (Tb). Because the thyroid hormones (THs) thyroxine (T4) and triiodothyronine (T3) are positive regulators of RMR and Tb, we hypothesized that serum TH concentrations would also be downregulated under hypoxic conditions. To test this hypothesis, we kept Ansell's mole-rats (Fukomys anselli) in terraria filled with soil in which they were allowed to construct underground burrows to achieve chronic intermittent hypoxia and hypercapnia. The animals stayed in these hypoxic and hypercapnic burrows voluntarily, although given the choice to stay aboveground. We collected blood samples before and after treatment to measure serum T4 and T3 concentrations as well as hematological parameters. The free fraction of the transcriptionally-active T3 was significantly decreased after treatment, indicating that cellular TH signaling was downregulated via peripheral mechanisms, consistent with the assumption that aerobic metabolism is downregulated under hypoxic conditions. Furthermore, we found that hematocrit and hemoglobin concentrations were also downregulated after treatment, suggesting that oxygen demand decreases under hypoxia, presumably due to the metabolic shift towards anaerobic metabolism. Taken together, we have identified a potential upstream regulator of physiological adaptations to hypoxia in these highly hypoxia-tolerant animals.
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Affiliation(s)
- Yoshiyuki Henning
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany.
| | - Kamilla Adam
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Patricia Gerhardt
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
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Farag A, Mandour AS, Hendawy H, Elhaieg A, Elfadadny A, Tanaka R. A review on experimental surgical models and anesthetic protocols of heart failure in rats. Front Vet Sci 2023; 10:1103229. [PMID: 37051509 PMCID: PMC10083377 DOI: 10.3389/fvets.2023.1103229] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
Heart failure (HF) is a serious health and economic burden worldwide, and its prevalence is continuously increasing. Current medications effectively moderate the progression of symptoms, and there is a need for novel preventative and reparative treatments. The development of novel HF treatments requires the testing of potential therapeutic procedures in appropriate animal models of HF. During the past decades, murine models have been extensively used in fundamental and translational research studies to better understand the pathophysiological mechanisms of HF and develop more effective methods to prevent and control congestive HF. Proper surgical approaches and anesthetic protocols are the first steps in creating these models, and each successful approach requires a proper anesthetic protocol that maintains good recovery and high survival rates after surgery. However, each protocol may have shortcomings that limit the study's outcomes. In addition, the ethical regulations of animal welfare in certain countries prohibit the use of specific anesthetic agents, which are widely used to establish animal models. This review summarizes the most common and recent surgical models of HF and the anesthetic protocols used in rat models. We will highlight the surgical approach of each model, the use of anesthesia, and the limitations of the model in the study of the pathophysiology and therapeutic basis of common cardiovascular diseases.
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Affiliation(s)
- Ahmed Farag
- Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology, Fuchu, Japan
- Department of Surgery, Anesthesiology, and Radiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
- *Correspondence: Ahmed Farag
| | - Ahmed S. Mandour
- Department of Animal Medicine (Internal Medicine), Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
- Ahmed S. Mandour
| | - Hanan Hendawy
- Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Asmaa Elhaieg
- Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Ahmed Elfadadny
- Department of Animal Internal Medicine, Faculty of Veterinary Medicine, Damanhur University, Damanhur El-Beheira, Egypt
| | - Ryou Tanaka
- Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology, Fuchu, Japan
- Ryou Tanaka
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5
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Comparative analysis of thyroid hormone systems in rodents with subterranean lifestyle. Sci Rep 2023; 13:3122. [PMID: 36813840 PMCID: PMC9946999 DOI: 10.1038/s41598-023-30179-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
African mole-rats are subterranean rodents inhabiting underground burrows. This habitat entails risks of overheating, hypoxia, and scarce food availability. Consequently, many subterranean species have evolved low basal metabolism and low body temperature, but the regulation of these traits at the molecular level were unknown. Measurements of serum thyroid hormone (TH) concentrations in African mole-rats have revealed a unique TH phenotype, which deviates from the typical mammalian pattern. Since THs are major regulators of metabolic rate and body temperature, we further characterised the TH system of two African mole-rat species, the naked mole-rat (Heterocephalus glaber) and the Ansell's mole-rat (Fukomys anselli) at the molecular level in a comparative approach involving the house mouse (Mus musculus) as a well-studied laboratory model in TH research. Most intriguingly, both mole-rat species had low iodide levels in the thyroid and naked mole-rats showed signs of thyroid gland hyperplasia. However, contrary to expectations, we found several species-specific differences in the TH systems of both mole-rat species, although ultimately resulting in similar serum TH concentrations. These findings indicate a possible convergent adaptation. Thus, our study adds to our knowledge for understanding adaptations to the subterranean habitat.
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Perioral secretions enable complex social signaling in African mole-rats (genus Fukomys). Sci Rep 2022; 12:22366. [PMID: 36572727 PMCID: PMC9792591 DOI: 10.1038/s41598-022-26351-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Subterranean common mole-rats of the genus Fukomys (family Bathyergidae) live in large, cooperatively-breeding families. Odor cues have been hypothesized to play an important role in mediating social behaviors in the underground ecotope, but only little is known about the role of olfactory signaling in burrowing mammals. Here we characterize the so far neglected perioral glands of Fukomys and other African mole-rats as an important source of olfactory social information. Histology demonstrates these structures to be derived sebaceous glands that are developed regardless of sex and reproductive status. However, gland activity is higher in Fukomys males, leading to sexually dimorphic patterns of stain and clotting of the facial pelage. Behavioral assays revealed that conspecifics prefer male but not female perioral swabs over scent samples from the back fur and that male sebum causes similar attraction as anogenital scent, a known source of social information in Fukomys. Finally, we assessed volatile compounds in the perioral sebum of the giant mole-rat (Fukomys mechowii) via GCxGC-MS-based metabolomic profiling. Volatiles display pronounced sex-specific signatures but also allow to differentiate between intrasexual reproductive status groups. These different lines of evidence suggest that mole-rat perioral glands provide complex odor signals which play a crucial role in social communication.
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MEDETOMIDINE-KETAMINE-BUPRENORPHINE ANESTHESIA OF THE SOLITARY SUBTERRANEAN CAPE DUNE MOLE-RAT ( BATHYERGUS SUILLUS) AND THE CAPE MOLE-RAT ( GEORYCHUS CAPENSIS). J Zoo Wildl Med 2022; 53:357-362. [PMID: 35758577 DOI: 10.1638/2019-0164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/26/2021] [Indexed: 11/21/2022] Open
Abstract
A prospective, descriptive study was conducted to evaluate the safety and efficacy of a field-ready anesthetic drug combination of medetomidine-ketamine-buprenorphine for data logger implantation surgery or recheck in free-ranging Cape dune (Bathyergus suillus: n = 41) and Cape (Georychus capensis: n = 37) mole-rats. All anesthesia data were reported as mean (±standard deviation). Medetomidine-ketamine-buprenorphine doses were 0.1 (±0.03), 10.6 (±2.8), and 0.06 (±0.03) mg/kg, respectively, for Cape dune mole-rats; and 0.2 (±0.03), 19.4 (±4.0), and 0.14 (±0.03) mg/kg, respectively, for Cape mole-rats. Induction was calm and took 2.00 (range: 1.00-6.00) min for the Cape dune and 1.75 (range 1.25 to 8.16) min for Cape mole-rats. A surgical plane of anesthesia was achieved in most Cape dune mole-rats (92%) and Cape mole-rats (90%). The remainder required supplementation with a single intramuscular injection of ketamine (3-9 mg/kg) during surgery. Heart and respiratory rates were 149 (±37) beats and 24 (±8) breaths per minute, respectively, for Cape dune mole-rats and 179 (±40) beats and 25 (±10) and breaths per minute, respectively for Cape mole-rats. Surgical time for mole-rats ranged from 25 to 38 min. Recovery was calm and took 8.50 (range: 2.00-19.00) min for Cape dune mole-rats and 9.75 (range: 2.00-34.00) min for Cape mole-rats to recover. For recovery, atipamezole was administered intramuscularly at 0.5 (±0.15) mg/kg for Cape dune mole-rats and 1 (±0.15) mg/kg for Cape mole-rats. All mole-rats were returned to their original burrows within 48 h of recovery. The medetomidine-ketamine-buprenorphine combination induced a predictable, safe anesthesia in Cape dune and Cape mole-rats suitable for short intraabdominal surgery. This combination is suited to in situ studies where the use of a formal surgery or laboratory is not feasible.
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8
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Caspar KR, Heinrich A, Mellinghaus L, Gerhardt P, Begall S. Evoked auditory potentials from African mole-rats and coruros reveal disparity in subterranean rodent hearing. J Exp Biol 2021; 224:272630. [PMID: 34704596 DOI: 10.1242/jeb.243371] [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: 08/19/2021] [Accepted: 10/22/2021] [Indexed: 12/28/2022]
Abstract
Hearing in subterranean rodents exhibits numerous peculiarities, including low sensitivity and restriction to a narrow range of comparatively low frequencies. Past studies provided two conflicting hypotheses explaining how these derived traits evolved: structural degeneration and adaptive specialization. To further elucidate this issue, we recorded auditory brainstem responses from three species of social subterranean rodents that differ in the degree of specialization to the underground habitat: the naked mole-rat (Heterocephalus glaber) and the Mashona mole-rat (Fukomys darlingi), which represent the ancient lineage of African mole-rats (Bathyergidae), and the coruro (Spalacopus cyanus), a South American rodent (Octodontidae) that adopted a subterranean lifestyle in more recent geological time. Additionally, we measured call amplitudes of social vocalizations to study auditory vocal coupling. We found elevated auditory thresholds and severe hearing range restrictions in the African mole-rats, with hearing in naked mole-rats tending to be more sensitive than in Mashona mole-rats, in which hearing notably deteriorated with increasing age. In contrast, hearing in coruros was similar to that of epigeic rodents, with its range extending into ultrasonic frequencies. However, as in the mole-rats, the coruros' region of best hearing was located at low frequencies close to 1 kHz. We argue that the auditory sensitivity of African mole-rats, although remarkably poor, has been underestimated by recent studies, whereas data on coruros conform to previous results. Considering the available evidence, we propose to be open to both degenerative and adaptive interpretations of hearing physiology in subterranean mammals, as each may provide convincing explanations for specific auditory traits observed.
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Affiliation(s)
- Kai R Caspar
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
| | - Alexandra Heinrich
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
| | - Lea Mellinghaus
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
| | - Patricia Gerhardt
- Institute of Physiology, Faculty of Medicine, University of Duisburg-Essen, 45147 Essen, Germany
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
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9
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Sahm A, Platzer M, Koch P, Henning Y, Bens M, Groth M, Burda H, Begall S, Ting S, Goetz M, Van Daele P, Staniszewska M, Klose JM, Costa PF, Hoffmann S, Szafranski K, Dammann P. Increased longevity due to sexual activity in mole-rats is associated with transcriptional changes in the HPA stress axis. eLife 2021; 10:57843. [PMID: 33724179 PMCID: PMC8012063 DOI: 10.7554/elife.57843] [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: 04/15/2020] [Accepted: 03/15/2021] [Indexed: 02/06/2023] Open
Abstract
Sexual activity and/or reproduction are associated with a doubling of life expectancy in the long-lived rodent genus Fukomys. To investigate the molecular mechanisms underlying this phenomenon, we analyzed 636 RNA-seq samples across 15 tissues. This analysis suggests that changes in the regulation of the hypothalamic–pituitary–adrenal stress axis play a key role regarding the extended life expectancy of reproductive vs. non-reproductive mole-rats. This is substantiated by a corpus of independent evidence. In accordance with previous studies, the up-regulation of the proteasome and so-called ‘anti-aging molecules’, for example, dehydroepiandrosterone, is linked with enhanced lifespan. On the other hand, several of our results are not consistent with knowledge about aging of short-lived model organisms. For example, we found the up-regulation of the insulin-like growth factor 1/growth hormone axis and several other anabolic processes to be compatible with a considerable lifespan prolongation. These contradictions question the extent to which findings from short-lived species can be transferred to longer-lived ones.
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Affiliation(s)
- Arne Sahm
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Matthias Platzer
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Philipp Koch
- Core Facility Life Science Computing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Yoshiyuki Henning
- Institute of Physiology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Martin Bens
- Core Facility Sequencing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Marco Groth
- Core Facility Sequencing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Hynek Burda
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Saskia Ting
- Institute of Pathology and Neuropathology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Moritz Goetz
- Institute of Pathology and Neuropathology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Paul Van Daele
- Department of Zoology, University of South Bohemia, České Budějovice, Czech Republic
| | - Magdalena Staniszewska
- Department of Nuclear Medicine, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Jasmin Mona Klose
- Department of Nuclear Medicine, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Steve Hoffmann
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Karol Szafranski
- Core Facility Life Science Computing, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Philip Dammann
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Central Animal Laboratory, University Hospital, University of Duisburg-Essen, Essen, Germany
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Braude S, Holtze S, Begall S, Brenmoehl J, Burda H, Dammann P, Marmol D, Gorshkova E, Henning Y, Hoeflich A, Höhn A, Jung T, Hamo D, Sahm A, Shebzukhov Y, Šumbera R, Miwa S, Vyssokikh MY, Zglinicki T, Averina O, Hildebrandt TB. Surprisingly long survival of premature conclusions about naked mole‐rat biology. Biol Rev Camb Philos Soc 2020; 96:376-393. [DOI: 10.1111/brv.12660] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Stan Braude
- Biology Department Washington University, One Brookings Drive St. Louis MO 63130 U.S.A
| | - Susanne Holtze
- Department of Reproduction Management Leibniz‐Institute for Zoo and Wildlife Research Berlin 10315 Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology University of Duisburg‐Essen, Universitätsstr Essen 45147 Germany
| | - Julia Brenmoehl
- Institute for Genome Biology Leibniz‐Institute for Farm Animal Biology Dummerstorf 18196 Germany
| | - Hynek Burda
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences Czech University of Life Sciences Praha 16500 Czech Republic
| | - Philip Dammann
- Department of General Zoology, Faculty of Biology University of Duisburg‐Essen, Universitätsstr Essen 45147 Germany
- University Hospital Essen Hufelandstr Essen 45141 Germany
| | - Delphine Marmol
- Molecular Physiology Research Unit (URPhyM), NARILIS University of Namur Namur 5000 Belgium
| | - Ekaterina Gorshkova
- Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vavilova str. 32 Moscow 119991 Russia
- Faculty of Biology Lomonosov Moscow State University Moscow 119991 Russia
| | - Yoshiyuki Henning
- University Hospital Essen Hufelandstr Essen 45141 Germany
- Institute of Physiology Department of General Zoology University of Duisburg Essen Germany
| | - Andreas Hoeflich
- Division Signal Transduction Institute for Genome Biology, Leibniz‐Institute for Farm Animal Biology, FBN Dummerstorf, Wilhelm‐Stahl‐Allee 2 Dummerstorf 18196 Germany
| | - Annika Höhn
- Department of Molecular Toxicology German Institute of Human Nutrition (DIfE) Potsdam‐Rehbrücke Nuthetal 14558 Germany
- German Center for Diabetes Research (DZD) München‐Neuherberg 85764 Germany
| | - Tobias Jung
- Department of Molecular Toxicology German Institute of Human Nutrition (DIfE) Potsdam‐Rehbrücke Nuthetal 14558 Germany
| | - Dania Hamo
- Charité ‐ Universitätsmedizin Berlin Berlin Institute of Health Center for Regenerative Therapies (BCRT) Berlin 13353 Germany
- German Rheumatism Research Centre Berlin (DRFZ) Berlin 10117 Germany
| | - Arne Sahm
- Computational Biology Group Leibniz Institute on Aging – Fritz Lipmann Institute Jena 07745 Germany
| | - Yury Shebzukhov
- Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vavilova str. 32 Moscow 119991 Russia
- Charité ‐ Universitätsmedizin Berlin Berlin Institute of Health Center for Regenerative Therapies (BCRT) Berlin 13353 Germany
| | - Radim Šumbera
- Faculty of Science University of South Bohemia České Budějovice 37005 Czech Republic
| | - Satomi Miwa
- Biosciences Institute, Edwardson building, Campus for Ageing and Vitality Newcastle University Newcastle upon Tyne NE4 5PL U.K
| | - Mikhail Y. Vyssokikh
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow 119991 Russia
| | - Thomas Zglinicki
- Biosciences Institute, Edwardson building, Campus for Ageing and Vitality Newcastle University Newcastle upon Tyne NE4 5PL U.K
| | - Olga Averina
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow 119991 Russia
| | - Thomas B. Hildebrandt
- Department of Reproduction Management Leibniz‐Institute for Zoo and Wildlife Research Berlin 10315 Germany
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11
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ANESTHETIC EFFECT OF DEXMEDETOMIDINE-KETAMINEMIDAZOLAM COMBINATION ADMINISTERED INTRAMUSCULARLY TO ZOO-HOUSED NAKED MOLE-RATS ( HETEROCEPHALUS GLABER). J Zoo Wildl Med 2020; 51:59-66. [PMID: 32212547 DOI: 10.1638/2019-0121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2019] [Indexed: 11/21/2022] Open
Abstract
In this study, adult intact male and female (n = 10) naked mole-rats (Heterocephalus glaber) were anesthetized using a combination of dexmedetomidine (0.06 mg/kg intramuscularly [IM]), ketamine (20 mg/kg IM), and midazolam (1.0 mg/kg IM). Atipamezole (1.0 mg/kg IM) and flumazenil (0.1 mg/kg IM) were administered 40 min after induction. Induction and recovery times were monitored and recorded. Vital parameters, including heart rate, respiratory rate, and SpO2, and reflexes were monitored every 5 min during the anesthetic period. Anesthetic induction was smooth and rapid. All monitored reflexes were lost within a median time of 60 sec (interquartile range, 15 sec). Heart rate and respiratory rate were significantly decreased from baseline, whereas there was no difference in SpO2 over the anesthetic period. The mean time to recovery was 15 ± 7 min (mean ± SD). One animal was found dead 40 min after apparent recovery, which is suspected to be an anesthetic-related death. Based on these findings, dexmedetomidine-ketamine-midazolam anesthesia is an effective anesthetic protocol in naked mole rats that provides a consistent anesthetic plane but should be used with caution in animals with underlying conditions.
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Ambar N, Eshar D, Shrader TC, Beaufrère H. Anesthetic Effects of Intramuscular Alfaxalone-Ketamine in Naked Mole Rats ( Heterocephalus glaber). JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE 2020; 59:539-545. [PMID: 32680579 DOI: 10.30802/aalas-jaalas-19-000170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, adult intact male and female (n = 10) naked mole rats (Heterocephalus glaber) were anesthetized by using a combination of ketamine (20 mg/kg IM), and alfaxalone (4.0 mg/kg IM). Induction and recovery times were recorded. Vital parameters, including heart rate, respiratory rate, and reflexes, were monitored every 5 min during the anesthetic period. Anesthetic induction was smooth and rapid. Induction time was significantly longer in male rats (median, 325 s; range, 180 to 385 s) than in females (median, 145 s; range, 118 to 180 s). In addition, overall duration of loss of righting reflex was shorter in male mole rats (median, 50 min; range, 36 to 65 min) than females (median, 70 min; range, 60 to 85 min). Males largely had intact withdrawal reflexes, whereas females showed variable loss of both forelimb and hindlimb withdrawal reflexes. Neither recovery time (mean ± 1 SD, 16 ± 13 min) nor vital parameters differed between sexes. None of animals showed any anesthesia-related adverse responses. According to these findings, intramuscular AK is a safe and effective protocol that provides brief, light anesthesia in male naked mole rats and deeper anesthesia in females. We recommend adding analgesics when this AK protocol is used for pain-inducing or invasive procedures, and further studies evaluating higher doses and different combinations are indicated.
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Affiliation(s)
- Neta Ambar
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas;,
| | - David Eshar
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | | | - Hugues Beaufrère
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Canada
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Eshar D, Huckins GL, Shrader TC, Beaufrère H. Comparison of intramuscular administration of alfaxalone-ketamine-dexmedetomidine and alfaxalone-butorphanol-midazolam in naked mole-rats ( Heterocephalus glaber). Am J Vet Res 2020; 80:1089-1098. [PMID: 31763939 DOI: 10.2460/ajvr.80.12.1089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare anesthetic effects of alfaxalone-ketamine-dexmedetomidine (AKD) and alfaxalone-butorphanol-midazolam (ABM) in naked mole-rats (Heterocephalus glaber). ANIMALS 20 naked mole-rats. PROCEDURES Naked mole-rats received AKD (alfaxalone, 2 mg/kg; ketamine, 20 mg/kg; and dexmedetomidine, 0.02 mg/kg; n = 10) or ABM (alfaxalone, 2 mg/kg; butorphanol, 2 mg/kg; and midazolam, 1 mg/kg; 9) IM; 1 animal was removed from the study. Atipamezole (I mg/kg) and flumazenil (0.1 mg/kg) were administered 40 minutes after anesthetic induction (defined as loss of the righting reflex) with AKD and ABM, respectively. Heart rate, respiratory rate, oxygen saturation, and reflexes were recorded every 5 minutes. RESULTS The ABM group had significantly longer median times for induction and recovery than the AKD group. Administration of ABM resulted in significantly lower respiratory rates than administration of AKD from time of anesthetic induction to 10 minutes after induction. Respiratory rate significantly decreased in the AKD group from I0 minutes after induction through the end of the anesthetic period but did not change over time in the ABM group. Males had higher respiratory rates in both groups. Loss of the righting reflex was still evident 40 minutes after induction in both groups. In the AKD group, all tested reflexes were absent from I0 to 40 minutes after induction; the ABM group had variable reflexes that recovered within individual animals over time. CONCLUSIONS AND CLINICAL RELEVANCE Both AKD and ABM provided effective immobilization in naked mole-rats, but AKD appeared to provide more consistent and deeper anesthesia, compared with administration of ABM.
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Dollas A, Oelschläger HHA, Begall S, Burda H, Malkemper EP. Brain atlas of the African mole-rat Fukomys anselli. J Comp Neurol 2019; 527:1885-1900. [PMID: 30697737 PMCID: PMC6593805 DOI: 10.1002/cne.24647] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/21/2018] [Accepted: 12/26/2018] [Indexed: 11/06/2022]
Abstract
African mole-rats are subterranean rodents that spend their whole life in underground burrow systems. They show a range of morphological and physiological adaptations to their ecotope, for instance severely reduced eyes and specialized somatosensory, olfactory, and auditory systems. These adaptations are also reflected in the accessory sensory pathways in the brain that process the input coming from the sensory organs. So far, a brain atlas was available only for the naked mole-rat (Heterocephalus glaber). The Ansell's mole-rat (Fukomys anselli) has been the subject of many investigations in various disciplines (ethology, sensory physiology, and anatomy) including magnetic orientation. It is therefore surprising that an atlas of the brain of this species was not available so far. Here, we present a comprehensive atlas of the Ansell's mole-rat brain based on Nissl and Klüver-Barrera stained sections. We identify and label 375 brain regions and discuss selected differences from the brain of the closely related naked mole-rat as well as from epigeic mammals (rat), with a particular focus on the auditory brainstem. This atlas can serve as a reference for future neuroanatomical investigations of subterranean mammals.
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Affiliation(s)
- Alexa Dollas
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
| | - Helmut H. A. Oelschläger
- Department of Anatomy III (Dr. Senckenbergische Anatomie), Medical FacultyJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Sabine Begall
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood Sciences, Czech University of Life SciencesPraha 6Czech Republic
| | - Hynek Burda
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood Sciences, Czech University of Life SciencesPraha 6Czech Republic
| | - Erich Pascal Malkemper
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC), Campus‐Vienna‐Biocenter 1Vienna 1030Austria
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Haseeb A, Tarique I, Iqbal A, Gandahi NS, Ali Vistro W, Bai X, Liang Y, Huang Y, Chen H, Chen Q, Yang P. Characterization of multilamellar bodies and telocytes within the testicular interstitium of naked mole rat Heterocephalus glabe. Theriogenology 2019; 138:111-120. [PMID: 31325741 DOI: 10.1016/j.theriogenology.2019.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 02/06/2023]
Abstract
Multilamellar bodies (MLBs) are produced and secreted by many cell types. In this study, we report the existence and ultrastructure of MLBs that are produced by Leydig cells and identification of telocytes in the testicular interstitium of naked mole rat. This study was performed on both breeder and non-breeder male naked mole rats using light microscopy, transmission electron microscopy, and morphometric approaches. In the testicular interstitium, the most prominent cells were Leydig cells, which contained numerous lipid droplets (LDs) in the cytoplasm. We found that MLBs were associated with the LDs of Leydig cells and were secreted into the extracellular or interstitial environment via exocytosis. After their release from Leydig cells, MLBs localized to the space between Leydig cells near blood vessels and attached to telocytes. We also identified telocytes in the testicular interstitium, and their cellular extensions were distributed throughout the interstitium. MLBs were aligned along the cellular extensions of telocytes, and membrane-to-membrane contact was observed between the cellular extensions of telocytes and MLBs, suggesting that telocytes may play a role in the transport of MLBs within the interstitial space. No ultrastructural differences were found in Leydig cells, telocytes, or MLBs between breeder and non-breeder testes. However, morphometric analysis revealed a significant difference in the number of MLBs between the breeder and non-breeder animals. Furthermore, both selective autophagy of LDs and non-selective autophagy were observed in Leydig cells. Typical features of macrolipophagy were also observed, as a few LDs were entirely enclosed by a limiting membrane. Remarkably, autophagy may be a key factor in the biogenesis of MLBs and steroid hormone production. The appearance of MLBs in the testicular interstitium of naked mole rats could thus be related to lipid storage and trafficking.
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Affiliation(s)
- Abdul Haseeb
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China; Faculty of Veterinary and Animal Sciences, University of Poonch Rawalakot, Azad Kashmir, Pakistan
| | - Imran Tarique
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Adeela Iqbal
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Noor Samad Gandahi
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Waseem Ali Vistro
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Xuebing Bai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Yu Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Yufei Huang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Hong Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Qiusheng Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China
| | - Ping Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province, 210095, China.
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Retinal S-opsin dominance in Ansell's mole-rats (Fukomys anselli) is a consequence of naturally low serum thyroxine. Sci Rep 2018. [PMID: 29531249 PMCID: PMC5847620 DOI: 10.1038/s41598-018-22705-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Mammals usually possess a majority of medium-wavelength sensitive (M-) and a minority of short-wavelength sensitive (S-) opsins in the retina, enabling dichromatic vision. Unexpectedly, subterranean rodents from the genus Fukomys exhibit an S-opsin majority, which is exceptional among mammals, albeit with no apparent adaptive value. Because thyroid hormones (THs) are pivotal for M-opsin expression and metabolic rate regulation, we have, for the first time, manipulated TH levels in the Ansell's mole-rat (Fukomys anselli) using osmotic pumps. In Ansell's mole-rats, the TH thyroxine (T4) is naturally low, likely as an adaptation to the harsh subterranean ecological conditions by keeping resting metabolic rate (RMR) low. We measured gene expression levels in the eye, RMR, and body mass (BM) in TH-treated animals. T4 treatment increased both, S- and M-opsin expression, albeit M-opsin expression at a higher degree. However, this plasticity was only given in animals up to approximately 2.5 years. Mass-specific RMR was not affected following T4 treatment, although BM decreased. Furthermore, the T4 inactivation rate is naturally higher in F. anselli compared to laboratory rodents. This is the first experimental evidence that the S-opsin majority in Ansell's mole-rats is a side effect of low T4, which is downregulated to keep RMR low.
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Gerhardt P, Henning Y, Begall S, Malkemper EP. Audiograms of three subterranean rodent species (genus Fukomys) determined by auditory brainstem responses reveal extremely poor high-frequency hearing. ACTA ACUST UNITED AC 2017; 220:4377-4382. [PMID: 29025871 DOI: 10.1242/jeb.164426] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/05/2017] [Indexed: 11/20/2022]
Abstract
Life underground has shaped the auditory sense of subterranean mammals, shifting their hearing range to low frequencies. Mole-rats of the genus Fukomys have, however, been suggested to hear at frequencies up to 18.5 kHz, unusually high for a subterranean rodent. We present audiograms of three mole-rat species, Fukomys anselli, Fukomys micklemi and the giant mole-rat Fukomys mechowii, based on evoked auditory brainstem potentials. All species showed low sensitivity and restricted hearing ranges at 60 dB SPL extending from 125 Hz to 4 kHz (5 octaves) with most-sensitive hearing between 0.8 kHz and 1.4 kHz. The high-frequency cut-offs are the lowest found in mammals to date. In contrast to predictions from middle ear morphology, F. mechowii did not show higher sensitivity than F. anselli in the low-frequency range. These data suggest that the hearing range of Fukomys mole-rats is highly restricted to low frequencies and similar to that of other subterranean mammals.
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Affiliation(s)
- Patricia Gerhardt
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - Yoshiyuki Henning
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - E Pascal Malkemper
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany .,Department of Wildlife Management, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521 Praha 6, Czech Republic
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Garcia Montero A, Vole C, Burda H, Malkemper EP, Holtze S, Morhart M, Saragusty J, Hildebrandt TB, Begall S. Non-Breeding Eusocial Mole-Rats Produce Viable Sperm--Spermiogram and Functional Testicular Morphology of Fukomys anselli. PLoS One 2016; 11:e0150112. [PMID: 26934488 PMCID: PMC4774953 DOI: 10.1371/journal.pone.0150112] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/09/2016] [Indexed: 11/26/2022] Open
Abstract
Ansell’s mole-rats (Fukomys anselli) are subterranean rodents living in families composed of about 20 members with a single breeding pair and their non-breeding offspring. Most of them remain with their parents for their lifetime and help to maintain and defend the natal burrow system, forage, and care for younger siblings. Since incest avoidance is based on individual recognition (and not on social suppression) we expect that non-breeders produce viable sperm spontaneously. We compared the sperm of breeding and non-breeding males, obtained by electroejaculation and found no significant differences in sperm parameters between both groups. Here, we used electroejaculation to obtain semen for the first time in a subterranean mammal. Spermiogram analysis revealed no significant differences in sperm parameters between breeders and non-breeders. We found significantly larger testes (measured on autopsies and on living animals per ultrasonography) of breeders compared to non-breeders (with body mass having a significant effect). There were no marked histological differences between breeding and non-breeding males, and the relative area occupied by Leydig cells and seminiferous tubules on histological sections, respectively, was not significantly different between both groups. The seminiferous epithelium and to a lesser degree the interstitial testicular tissue are characterized by lesions (vacuolar degenerations), however, this feature does not hinder fertilization even in advanced stages of life. The continuous production of viable sperm also in sexually abstinent non-breeders might be best understood in light of the mating and social system of Fukomys anselli, and the potential to found a new family following an unpredictable and rare encounter with an unfamiliar female (“provoked or induced dispersal”). Apparently, the non-breeders do not reproduce because they do not copulate but not because they would be physiologically infertile. The significantly increased testes volume of breeding males (compared to non-breeders) is in agreement with previously found higher testosterone levels of breeders.
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Affiliation(s)
- Angelica Garcia Montero
- Department of General Zoology, Faculty for Biology, University of Duisburg-Essen, Essen, Germany
| | - Christiane Vole
- Department of General Zoology, Faculty for Biology, University of Duisburg-Essen, Essen, Germany
| | - Hynek Burda
- Department of General Zoology, Faculty for Biology, University of Duisburg-Essen, Essen, Germany
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
| | - Erich Pascal Malkemper
- Department of General Zoology, Faculty for Biology, University of Duisburg-Essen, Essen, Germany
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
| | - Susanne Holtze
- Leibniz Institute for Zoo and Wildlife Research, Reproduction Management, Berlin, Germany
| | - Michaela Morhart
- Leibniz Institute for Zoo and Wildlife Research, Reproduction Management, Berlin, Germany
| | - Joseph Saragusty
- Leibniz Institute for Zoo and Wildlife Research, Reproduction Management, Berlin, Germany
| | - Thomas B. Hildebrandt
- Leibniz Institute for Zoo and Wildlife Research, Reproduction Management, Berlin, Germany
| | - Sabine Begall
- Department of General Zoology, Faculty for Biology, University of Duisburg-Essen, Essen, Germany
- * E-mail:
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Henning Y, Vole C, Begall S, Bens M, Broecker-Preuss M, Sahm A, Szafranski K, Burda H, Dammann P. Unusual ratio between free thyroxine and free triiodothyronine in a long-lived mole-rat species with bimodal ageing. PLoS One 2014; 9:e113698. [PMID: 25409169 PMCID: PMC4237498 DOI: 10.1371/journal.pone.0113698] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 10/27/2014] [Indexed: 12/03/2022] Open
Abstract
Ansell's mole-rats (Fukomys anselli) are subterranean, long-lived rodents, which live in eusocial families, where the maximum lifespan of breeders is twice as long as that of non-breeders. Their metabolic rate is significantly lower than expected based on allometry, and their retinae show a high density of S-cone opsins. Both features may indicate naturally low thyroid hormone levels. In the present study, we sequenced several major components of the thyroid hormone pathways and analyzed free and total thyroxine and triiodothyronine in serum samples of breeding and non-breeding F. anselli to examine whether a) their thyroid hormone system shows any peculiarities on the genetic level, b) these animals have lower hormone levels compared to euthyroid rodents (rats and guinea pigs), and c) reproductive status, lifespan and free hormone levels are correlated. Genetic analyses confirmed that Ansell's mole-rats have a conserved thyroid hormone system as known from other mammalian species. Interspecific comparisons revealed that free thyroxine levels of F. anselli were about ten times lower than of guinea pigs and rats, whereas the free triiodothyronine levels, the main biologically active form, did not differ significantly amongst species. The resulting fT4:fT3 ratio is unusual for a mammal and potentially represents a case of natural hypothyroxinemia. Comparisons with total thyroxine levels suggest that mole-rats seem to possess two distinct mechanisms that work hand in hand to downregulate fT4 levels reliably. We could not find any correlation between free hormone levels and reproductive status, gender or weight. Free thyroxine may slightly increase with age, based on sub-significant evidence. Hence, thyroid hormones do not seem to explain the different ageing rates of breeders and non-breeders. Further research is required to investigate the regulatory mechanisms responsible for the unusual proportion of free thyroxine and free triiodothyronine.
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Affiliation(s)
- Yoshiyuki Henning
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
- * E-mail:
| | - Christiane Vole
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Martin Bens
- Genome Analysis, Leibniz Institute for Age Research - Fritz Lipmann Institute, Jena, Germany
| | - Martina Broecker-Preuss
- Department of Endocrinology and Metabolism and Division of Laboratory Research, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Arne Sahm
- Genome Analysis, Leibniz Institute for Age Research - Fritz Lipmann Institute, Jena, Germany
| | - Karol Szafranski
- Genome Analysis, Leibniz Institute for Age Research - Fritz Lipmann Institute, Jena, Germany
| | - Hynek Burda
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Philip Dammann
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
- Central Animal Laboratory, University Hospital, University of Duisburg-Essen, Essen, Germany
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