1
|
Smith DL, Mitchell SE, Johnson MS, Gibbs VK, Dickinson S, Henschel B, Li R, Kaiser KA, Chusyd DE, Brown AW, Allison DB, Speakman JR, Nagy TR. Benefits of calorie restriction in mice are mediated via energy imbalance, not absolute energy or protein intake. GeroScience 2024; 46:4809-4826. [PMID: 38850387 PMCID: PMC11336014 DOI: 10.1007/s11357-024-01166-4] [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: 12/05/2023] [Accepted: 04/10/2024] [Indexed: 06/10/2024] Open
Abstract
Caloric restriction (CR) results in reduced energy and protein intake, raising questions about protein restriction's contribution to CR longevity benefits. We kept ad libitum (AL)-fed male C57BL/6J mice at 27°C (AL27) and pair-fed (PF) mice at 22°C (22(PF27)). The 22(PF27) group was fed to match AL27 while restricted for calories due to cold-induced metabolism. The 22(PF27) mice had significantly lower body weight, lean mass, fat mass, leptin, IGF-1, and TNF-α levels than AL27 mice (p<0.001 for all). Manipulations over ~11 weeks resulted in significant differences in body temperature, physical activity, and expression of key genes linked to hunger in the hypothalamus. Survival was significantly greater in 22(PF27) compared to AL27 overall (p<0.001). CR in the context of equivalent energy and protein intake resulted in hormonal, metabolic, and physiological benefits and extended longevity. Hence, energy imbalance, rather than low energy or protein intake per se, mediates the benefits of CR.
Collapse
Affiliation(s)
- Daniel L Smith
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
- Integrative Center for Aging Research, University of Alabama at Birmingham, Birmingham, AL, USA
- Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham, AL, USA
- Diabetes Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sharon E Mitchell
- School of Biological Sciences, University of Aberdeen, Aberdeen Scotland, Scotland, UK
| | - Maria S Johnson
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
- Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham, AL, USA
- Diabetes Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Victoria K Gibbs
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Clinical and Diagnostic Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stephanie Dickinson
- Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
| | - Beate Henschel
- Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
| | - Rui Li
- Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
| | - Kathryn A Kaiser
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Health Behavior, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniella E Chusyd
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Environmental and Occupational Health, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
| | - Andrew W Brown
- Department of Applied Health Science, Indiana University School of Public Health-Bloomington, Bloomington, IN, USA
- Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Arkansas Children's Research Institute, Little Rock, AR, USA
| | - David B Allison
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
- Integrative Center for Aging Research, University of Alabama at Birmingham, Birmingham, AL, USA.
- Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham, AL, USA.
- Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA.
| | - John R Speakman
- School of Biological Sciences, University of Aberdeen, Aberdeen Scotland, Scotland, UK.
- Shenzhen Key Laboratory for Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning, China.
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
| | - Tim R Nagy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
- Integrative Center for Aging Research, University of Alabama at Birmingham, Birmingham, AL, USA.
- Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham, AL, USA.
- Diabetes Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
2
|
Harmon ME, Fiamingo M, Toler S, Lee K, Kim Y, Martin B, Gilmour I, Farraj AK, Hazari MS. The effect of enriched versus depleted housing on eucalyptus smoke-induced cardiovascular dysfunction in mice. Inhal Toxicol 2024; 36:355-366. [PMID: 38776456 DOI: 10.1080/08958378.2024.2352748] [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: 11/19/2023] [Accepted: 04/30/2024] [Indexed: 05/25/2024]
Abstract
Objectives: Living conditions play a major role in health and well-being, particularly for the cardiovascular and pulmonary systems. Depleted housing contributes to impairment and development of disease, but how it impacts body resiliency during exposure to environmental stressors is unknown. This study examined the effect of depleted (DH) versus enriched housing (EH) on cardiopulmonary function and subsequent responses to wildfire smoke. Materials and Methods: Two cohorts of healthy female mice, one of them surgically implanted with radiotelemeters for the measurement of electrocardiogram, body temperature (Tco) and activity, were housed in either DH or EH for 7 weeks. Telemetered mice were exposed for 1 h to filtered air (FA) and then flaming eucalyptus wildfire smoke (WS) while untelemetered mice, which were used for ventilatory assessment and tissue collection, were exposed to either FA or WS. Animals were continuously monitored for 5-7 days after exposure. Results: EH prevented a decrease in Tco after radiotelemetry surgery. EH mice also had significantly higher activity levels and lower heart rate during and after FA and WS. Moreover, EH caused a decreased number of cardiac arrhythmias during WS. WS caused ventilatory depression in DH mice but not EH mice. Housing enrichment also upregulated the expression of cardioprotective genes in the heart. Conclusions: The results of this study indicate that housing conditions impact overall health and cardiopulmonary function. More importantly, depleted housing appears to worsen the response to air pollution. Thus, non-chemical factors should be considered when assessing the susceptibility of populations, especially when it comes to extreme environmental events.
Collapse
Affiliation(s)
- Molly E Harmon
- Curriculum in Toxicology and Environmental Medicine, University of NC - Chapel Hill, Chapel Hill, NC, USA
| | - Michelle Fiamingo
- Curriculum in Toxicology and Environmental Medicine, University of NC - Chapel Hill, Chapel Hill, NC, USA
| | - Sydnie Toler
- Gillings School of Global Public Health, University of North Carolina - Chapel Hill, Chapel Hill, NC, USA
| | - Kaleb Lee
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Yongho Kim
- Public Health Integrated Toxicology Division, Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, NC, USA
| | - Brandi Martin
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Ian Gilmour
- Public Health Integrated Toxicology Division, Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, NC, USA
| | - Aimen K Farraj
- Public Health Integrated Toxicology Division, Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, NC, USA
| | - Mehdi S Hazari
- Public Health Integrated Toxicology Division, Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, NC, USA
| |
Collapse
|
3
|
Golpich M, Amini E, Kefayat A, Fesharaki M, Moshtaghian J. In vitro and in vivo anti-cancer effects of hibernating common carp (Cyprinus carpio) plasma on metastatic triple-negative breast cancer. Sci Rep 2022; 12:2855. [PMID: 35190572 PMCID: PMC8861139 DOI: 10.1038/s41598-022-06368-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/28/2022] [Indexed: 11/28/2022] Open
Abstract
Uncontrollable proliferation is a hallmark of cancer cells. Cell proliferation and migration are significantly depressed during hibernation state. Many studies believe some factors in the plasma of hibernating animals cause these effects. This study aimed to assess the anti-cancer effects of hibernating common carp (Cyprinus carpio) plasma on 4T1 cancer cells in vitro and in vivo. The effect of hibernating plasma on cell viability, morphology, migration, apoptosis rate, and cell cycle distribution of 4T1 cells was investigated in vitro and in vivo. Hibernating plasma at a concentration of 16 mg/ml significantly reduced the viability of 4T1 cancer cells, without any toxicity on L929 normal fibroblast cells. It could change the morphology of cancer cells, induced apoptosis and cell cycle arrest at the G2/M phase, and inhibited migration. Furthermore, intratumoral injection of hibernating plasma (200 µl, 16 mg/ml) in the tumor-bearing mice caused a significant inhibition of 4T1 breast tumors volume (46.9%) and weight (58.8%) compared with controls. A significant decrease in the number of metastatic colonies at the lungs (80%) and liver (52.8%) of hibernating plasma-treated animals was detected which increased the survival time (21.9%) compared to the control groups. Immunohistochemical analysis revealed a considerable reduction in the Ki-67-positive cells in the tumor section of the hibernating plasma-treated animals compared with controls. Taken together, the SDS-PAGE and mass spectrometry analysis indicated the alpha-2-macroglobulin level in the hibernating fish plasma was significantly increased. It could exert an anti-cancer effect on breast cancer cells and suggested as a novel cancer treatment strategy.
Collapse
|
4
|
Eto T, Hidaka S, Shichijo H, Nagura-Kato GA, Morita T. Dietary Protein Deficiency Affects Food Consumption and Torpor in the African Woodland Dormouse (Graphiurus murinus). MAMMAL STUDY 2021. [DOI: 10.3106/ms2020-0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Takeshi Eto
- Interdisciplinary Graduate School of Agriculture and Engineering, Kibana Campus, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Sayako Hidaka
- Faculty of Agriculture, Kibana Campus, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Hiroki Shichijo
- Division of Bio-Resources, Frontier Science Research Center, Kiyotake Campus, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Goro A. Nagura-Kato
- Division of Bio-Resources, Frontier Science Research Center, Kiyotake Campus, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Tetsuo Morita
- Faculty of Agriculture, Kibana Campus, University of Miyazaki, Miyazaki 889-2192, Japan
| |
Collapse
|
5
|
Al-Attar R, Storey KB. Suspended in time: Molecular responses to hibernation also promote longevity. Exp Gerontol 2020; 134:110889. [PMID: 32114078 DOI: 10.1016/j.exger.2020.110889] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/16/2022]
Abstract
Aging in most animals is an inevitable process that causes or is a result of physiological, biochemical, and molecular changes in the body, and has a strong influence on an organism's lifespan. Although advancement in medicine has allowed humans to live longer, the prevalence of age-associated medical complications is continuously burdening older adults worldwide. Current animal models used in research to study aging have provided novel information that has helped investigators understand the aging process; however, these models are limiting. Aging is a complex process that is regulated at multiple biological levels, and while a single manipulation in these models can provide information on a process, it is not enough to understand the global regulation of aging. Some mammalian hibernators live up to 9.8-times higher than their expected average lifespan, and new research attributes this increase to their ability to hibernate. A common theme amongst these mammalian hibernators is their ability to greatly reduce their metabolic rate to a fraction of their normal rate and initiate cytoprotective responses that enable their survival. Metabolic rate depression is strictly regulated at different biological levels in order to enable the animal to not only survive, but to also do so by relying mainly on their limited internal fuels. As such, understanding both the global and specific regulatory mechanisms used to promote survival during hibernation could, in theory, allow investigators to have a better understanding of the aging process. This can also allow pharmaceutical industries to find therapeutics that could delay or reverse age-associated medical complications and promote healthy aging and longevity in humans.
Collapse
Affiliation(s)
- Rasha Al-Attar
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
| |
Collapse
|
6
|
The cascading effects of human food on hibernation and cellular aging in free-ranging black bears. Sci Rep 2019; 9:2197. [PMID: 30792484 PMCID: PMC6385323 DOI: 10.1038/s41598-019-38937-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/15/2019] [Indexed: 11/28/2022] Open
Abstract
Human foods have become a pervasive subsidy in many landscapes, and can dramatically alter wildlife behavior, physiology, and demography. While such subsidies can enhance wildlife condition, they can also result in unintended negative consequences on individuals and populations. Seasonal hibernators possess a remarkable suite of adaptations that increase survival and longevity in the face of resource and energetic limitations. Recent work has suggested hibernation may also slow the process of senescence, or cellular aging. We investigated how use of human foods influences hibernation, and subsequently cellular aging, in a large-bodied hibernator, black bears (Ursus americanus). We quantified relative telomere length, a molecular marker for cellular age, and compared lengths in adult female bears longitudinally sampled over multiple seasons. We found that bears that foraged more on human foods hibernated for shorter periods of time. Furthermore, bears that hibernated for shorter periods of time experienced accelerated telomere attrition. Together these results suggest that although hibernation may ameliorate cellular aging, foraging on human food subsidies could counteract this process by shortening hibernation. Our findings highlight how human food subsidies can indirectly influence changes in aging at the molecular level.
Collapse
|
7
|
Fischer AW, Cannon B, Nedergaard J. Optimal housing temperatures for mice to mimic the thermal environment of humans: An experimental study. Mol Metab 2017; 7:161-170. [PMID: 29122558 PMCID: PMC5784327 DOI: 10.1016/j.molmet.2017.10.009] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 10/12/2017] [Accepted: 10/21/2017] [Indexed: 11/05/2022] Open
Abstract
Objectives The laboratory mouse is presently the most common model for examining mechanisms of human physiology and disease. Housing temperatures can have a large impact on the outcome of such experiments and on their translatability to the human situation. Humans usually create for themselves a thermoneutral environment without cold stress, while laboratory mice under standard conditions (≈20° C) are under constant cold stress. In a well-cited, theoretical paper by Speakman and Keijer in Molecular Metabolism, it was argued that housing mice under close to standard conditions is the optimal way of modeling the human metabolic situation. This tenet was mainly based on the observation that humans usually display average metabolic rates of about 1.6 times basal metabolic rate. The extra heat thereby produced would also be expected to lead to a shift in the ‘lower critical temperature’ towards lower temperatures. Methods To examine these tenets experimentally, we performed high time-resolution indirect calorimetry at different environmental temperatures on mice acclimated to different housing temperatures. Results Based on the high time-resolution calorimetry analysis, we found that mice already under thermoneutral conditions display mean diurnal energy expenditure rates 1.8 times higher than basal metabolism, remarkably closely resembling the human situation. At any temperature below thermoneutrality, mice metabolism therefore exceeds the human equivalent: Mice under standard conditions display energy expenditure 3.1 times basal metabolism. The discrepancy to previous conclusions is probably attributable to earlier limitations in establishing true mouse basal metabolic rate, due to low time resolution. We also found that the fact that mean energy expenditure exceeds resting metabolic rate does not move the apparent thermoneutral zone (the lower critical temperature) downwards. Conclusions We show that housing mice at thermoneutrality is an advantageous step towards aligning mouse energy metabolism to human energy metabolism. High time-resolution indirect calorimetry reveals true resting metabolic rate in mice. Mice at thermoneutrality display average energy expenditure 1.8 times their RMR (BMR). This relationship very closely resembles the human situation. Lower critical temperature is not influenced by enhanced energy expenditure. To model human metabolism, 30 °C remains the optimal housing temperature for mice.
Collapse
Affiliation(s)
- Alexander W Fischer
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden; Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, DE-20246 Hamburg, Germany
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
| |
Collapse
|
8
|
Kato GA, Shichijo H, Takahashi T, Shinohara A, Morita T, Koshimoto C. Protein restriction does not affect body temperature pattern in female mice. Exp Anim 2017. [PMID: 28626157 PMCID: PMC5682344 DOI: 10.1538/expanim.17-0035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Daily torpor is a physiological adaptation in mammals and birds characterized by a
controlled reduction of metabolic rate and body temperature during the resting phase of
circadian rhythms. In laboratory mice, daily torpor is induced by dietary caloric
restriction. However, it is not known which nutrients are related to daily torpor
expression. To determine whether dietary protein is a key factor in inducing daily torpor
in mice, we fed mice a protein-restricted (PR) diet that included only one-quarter of the
amount of protein but the same caloric level as a control (C) diet. We assigned six
non-pregnant female ICR mice to each group and recorded their body weights and core body
temperatures for 4 weeks. Body weights in the C group increased, but those in the PR group
remained steady or decreased. Mice in both groups did not show daily torpor, but most mice
in a food-restricted group (n=6) supplied with 80% of the calories given to the C group
exhibited decreased body weights and frequently displayed daily torpor. This suggests that
protein restriction is not a trigger of daily torpor; torpid animals can conserve their
internal energy, but torpor may not play a significant role in conserving internal
protein. Thus, opportunistic daily torpor in mice may function in energy conservation
rather than protein saving.
Collapse
Affiliation(s)
- Goro A Kato
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan.,Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan.,Present address: Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, University of Kyushu, 3-1-1 Maidashi, Fukuoka, Fukuoka 812-8582, Japan
| | - Hiroki Shichijo
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Toshihiro Takahashi
- Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Akio Shinohara
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Tetsuo Morita
- Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Chihiro Koshimoto
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| |
Collapse
|
9
|
Gordon CJ. The mouse thermoregulatory system: Its impact on translating biomedical data to humans. Physiol Behav 2017; 179:55-66. [PMID: 28533176 PMCID: PMC6196327 DOI: 10.1016/j.physbeh.2017.05.026] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/04/2017] [Accepted: 05/18/2017] [Indexed: 01/01/2023]
Abstract
The laboratory mouse has become the predominant test species in biomedical research. The number of papers that translate or extrapolate data from mouse to human has grown exponentially since the year 2000. There are many physiological and anatomical factors to consider in the process of extrapolating data from one species to another. Body temperature is, of course, a critical determinant in extrapolation because it has a direct impact on metabolism, cardiovascular function, drug efficacy, pharmacokinetics of toxins and drugs, and many other effects. While most would consider the thermoregulatory system of mice to be sufficiently stable and predictable as to not be a cause for concern, the thermal physiology of mice does in fact present unique challenges to the biomedical researcher. A variable and unstable core temperature, high metabolic rate, preference for warm temperatures, large surface area: body mass ratio, and high rate of thermal conductance, are some of the key factors of mice that can affect the interpretation and translation of data to humans. It is the intent of this brief review to enlighten researchers studying interspecies translation of biomedical data on the salient facets of the mouse thermal physiology and show how extrapolation in fields such as physiology, psychology, nutrition, pharmacology, toxicology, and pathology.
Collapse
Affiliation(s)
- Christopher J Gordon
- Toxicity Assessment Division, National Health Effects and Environmental Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States.
| |
Collapse
|
10
|
Gibbs VK, Smith DL. Nutrition and energetics in rodent longevity research. Exp Gerontol 2016; 86:90-96. [PMID: 27073168 DOI: 10.1016/j.exger.2016.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 12/25/2022]
Abstract
The impact of calorie amount on aging has been extensively described; however, variation over time and among laboratories in animal diet, housing condition, and strains complicates discerning the true influence of calories (energy) versus nutrients on lifespan. Within the dietary restriction field, single macronutrient manipulations have historically been researched as a means to reduce calories while maintaining adequate levels of essential nutrients. Recent reports of nutritional geometry, including rodent models, highlight the impact macronutrients have on whole organismal aging outcomes. However, other environmental factors (e.g., ambient temperature) may alter nutrient preferences and requirements revealing context specific outcomes. Herein we highlight factors that influence the energetic and nutrient demands of organisms which oftentimes have underappreciated impacts on clarifying interventional effects on health and longevity in aging studies and subsequent translation to improve the human condition.
Collapse
Affiliation(s)
- Victoria K Gibbs
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Daniel L Smith
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| |
Collapse
|
11
|
Maloney SK, Fuller A, Mitchell D, Gordon C, Overton JM. Translating animal model research: does it matter that our rodents are cold? Physiology (Bethesda) 2015; 29:413-20. [PMID: 25362635 DOI: 10.1152/physiol.00029.2014] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Does it matter that rodents used as preclinical models of human biology are routinely housed below their thermoneutral zone? We compile evidence showing that such rodents are cold-stressed, hypermetabolic, hypertensive, sleep-deprived, obesity-resistant, fever-resistant, aging-resistant, and tumor-prone compared with mice housed at thermoneutrality. The same genotype of mouse has a very different phenotype and response to physiological or pharmacological intervention when raised below or at thermoneutrality.
Collapse
Affiliation(s)
- Shane K Maloney
- School of Anatomy Physiology and Human Biology, The University of Western Australia, Stirling Highway, Crawley, Australia; Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa
| | - Duncan Mitchell
- School of Anatomy Physiology and Human Biology, The University of Western Australia, Stirling Highway, Crawley, Australia; Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa
| | - Christopher Gordon
- Toxicity Assessment Division, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina; and
| | - J Michael Overton
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida
| |
Collapse
|
12
|
Hou C. Increasing Energetic Cost of Biosynthesis during Growth Makes Refeeding Deleterious. Am Nat 2014; 184:233-47. [DOI: 10.1086/676856] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
13
|
Turbill C, Ruf T, Smith S, Bieber C. Seasonal variation in telomere length of a hibernating rodent. Biol Lett 2013; 9:20121095. [PMID: 23389666 DOI: 10.1098/rsbl.2012.1095] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Small hibernating rodents have greater maximum lifespans and hence appear to age more slowly than similar-sized non-hibernators. We tested for a direct effect of hibernation on somatic maintenance and ageing by measuring seasonal changes in relative telomere length (RTL) in the edible dormouse Glis glis. Average RTL in our population did not change significantly over the hibernation season, and a regression model explaining individual variation in post-hibernation RTL suggested a significant negative effect of the reduction in body mass over the inactive hibernation period (an index of time spent euthermic), supporting the idea that torpor slows ageing. Over the active season, RTL on average decreased in sub-adults but increased in adults, supporting previous findings of greater telomere shortening at younger ages. Telomere length increase might also have been associated with reproduction, which occurred only in adults. Our study reveals how seasonal changes in physiological state influence the progress of life-history traits, such as somatic maintenance and ageing, in a small hibernating rodent.
Collapse
Affiliation(s)
- Christopher Turbill
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, Australia. c
| | | | | | | |
Collapse
|
14
|
|
15
|
Hou C, Bolt KM, Bergman A. A general model for ontogenetic growth under food restriction. Proc Biol Sci 2011; 278:2881-90. [PMID: 21345868 PMCID: PMC3151715 DOI: 10.1098/rspb.2011.0047] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 01/31/2011] [Indexed: 01/14/2023] Open
Abstract
Food restriction (FR) retards animals' growth. Understanding the underlying mechanisms of this phenomenon is important to conceptual problems in life-history theory, as well as to applied problems in animal husbandry and biomedicine. Despite a considerable amount of empirical data published since the 1930s, there is no relevant general theoretical framework that predicts how animals vary their energy budgets and life-history traits under FR. In this paper, we develop such a general quantitative model based on fundamental principles of metabolic energy allocation during ontogeny. This model predicts growth curves under varying conditions of FR, such as the compensatory growth, different age at which FR begins, its degree and its duration. Our model gives a quantitative explanation for the counterintuitive phenomenon that under FR, lower body temperature and lower metabolism lead to faster growth and larger adult size. This model also predicts that the animals experiencing FR reach the same fraction of their adult mass at the same age as their ad libitum counterparts. All predictions are well supported by empirical data from mammals and birds of varying body size, under different conditions of FR.
Collapse
Affiliation(s)
| | | | - Aviv Bergman
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| |
Collapse
|
16
|
Turbill C, Smith S, Deimel C, Ruf T. Daily torpor is associated with telomere length change over winter in Djungarian hamsters. Biol Lett 2011; 8:304-7. [PMID: 21920955 DOI: 10.1098/rsbl.2011.0758] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Ageing can progress at different rates according to an individual's physiological state. Natural hypothermia, including torpor and hibernation, is a common adaptation of small mammals to survive intermittent or seasonal declines in environmental conditions. In addition to allowing energy savings, hypothermia and torpor have been associated with retarded ageing and increased longevity. We tested the hypothesis that torpor use slows ageing by measuring changes in the relative telomere length (RTL) of Djungarian hamsters, Phodopus sungorus, a highly seasonal rodent using spontaneous daily torpor, over 180 days of exposure to a short-day photoperiod and warm (approx. 20°C) or cold (approx. 9°C) air temperatures. Multi-model inference showed that change in RTL within individuals was best explained by positive effects of frequency of torpor use, particularly at low body temperatures, as well as the change in body mass and initial RTL. Telomere dynamics have been linked to future survival and proposed as an index of rates of biological ageing. Our results therefore support the hypothesis that daily torpor is associated with physiological changes that increase somatic maintenance and slow the processes of ageing.
Collapse
Affiliation(s)
- Christopher Turbill
- Department of Integrative Biology and Ecology, Research Institute for Wildlife Ecology, University of Veterinary Medicine, Vienna 1160, Austria.
| | | | | | | |
Collapse
|
17
|
Liao CY, Rikke BA, Johnson TE, Gelfond JAL, Diaz V, Nelson JF. Fat maintenance is a predictor of the murine lifespan response to dietary restriction. Aging Cell 2011; 10:629-39. [PMID: 21388497 DOI: 10.1111/j.1474-9726.2011.00702.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Dietary restriction (DR), one of the most robust life-extending manipulations, is usually associated with reduced adiposity. This reduction is hypothesized to be important in the life-extending effect of DR, because excess adiposity is associated with metabolic and age-related disease. Previously, we described remarkable variation in the lifespan response of 41 recombinant inbred strains of mice to DR, ranging from life extension to life shortening. Here, we used this variation to determine the relationship of lifespan modulation under DR to fat loss. Across strains, DR life extension correlated inversely with fat reduction, measured at midlife (males, r= -0.41, P<0.05, n=38 strains; females, r= -0.63, P<0.001, n=33 strains) and later ages. Thus, strains with the least reduction in fat were more likely to show life extension, and those with the greatest reduction were more likely to have shortened lifespan. We identified two significant quantitative trait loci (QTLs) affecting fat mass under DR in males but none for lifespan, precluding the confirmation of these loci as coordinate modulators of adiposity and longevity. Our data also provide evidence for a QTL previously shown to affect fuel efficiency under DR. In summary, the data do not support an important role for fat reduction in life extension by DR. They suggest instead that factors associated with maintaining adiposity are important for survival and life extension under DR.
Collapse
Affiliation(s)
- Chen-Yu Liao
- Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | | | | | | | | | | |
Collapse
|
18
|
|
19
|
Lee C, Longo VD. Fasting vs dietary restriction in cellular protection and cancer treatment: from model organisms to patients. Oncogene 2011; 30:3305-16. [PMID: 21516129 DOI: 10.1038/onc.2011.91] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The dietary recommendation for cancer patients receiving chemotherapy, as described by the American Cancer Society, is to increase calorie and protein intake. Yet, in simple organisms, mice, and humans, fasting--no calorie intake--induces a wide range of changes associated with cellular protection, which would be difficult to achieve even with a cocktail of potent drugs. In mammals, the protective effect of fasting is mediated, in part, by an over 50% reduction in glucose and insulin-like growth factor 1 (IGF-I) levels. Because proto-oncogenes function as key negative regulators of the protective changes induced by fasting, cells expressing oncogenes, and therefore the great majority of cancer cells, should not respond to the protective signals generated by fasting, promoting the differential protection (differential stress resistance) of normal and cancer cells. Preliminary reports indicate that fasting for up to 5 days followed by a normal diet, may also protect patients against chemotherapy without causing chronic weight loss. By contrast, the long-term 20 to 40% restriction in calorie intake (dietary restriction, DR), whose effects on cancer progression have been studied extensively for decades, requires weeks-months to be effective, causes much more modest changes in glucose and/or IGF-I levels, and promotes chronic weight loss in both rodents and humans. In this study, we review the basic as well as clinical studies on fasting, cellular protection and chemotherapy resistance, and compare them to those on DR and cancer treatment. Although additional pre-clinical and clinical studies are necessary, fasting has the potential to be translated into effective clinical interventions for the protection of patients and the improvement of therapeutic index.
Collapse
Affiliation(s)
- C Lee
- Andrus Gerontology Center, Department of Biological Sciences and Norris Cancer Center, University of Southern California, Los Angeles, CA 90089-0191, USA
| | | |
Collapse
|
20
|
Tanner JM, Kearns DT, Kim BJ, Sloan C, Jia Z, Yang T, Abel ED, Symons JD. Fasting-induced reductions in cardiovascular and metabolic variables occur sooner in obese versus lean mice. Exp Biol Med (Maywood) 2011; 235:1489-97. [PMID: 21127345 DOI: 10.1258/ebm.2010.010171] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is not uncommon for laboratory animals to be fasted prior to experimentation. Fasting evokes marked reductions in heart rate (HR), blood pressure (BP), heat production and oxygen consumption (VO(2)) in rodents. Mice with diet-induced obesity exhibit elevated HR and BP, and lower VO(2) and heat production in the fed condition versus their lean counterparts. It is unknown whether body composition alters the tempo of response to fasting. We tested the hypothesis that cardiovascular and metabolic responses to fasting are delayed in obese versus lean male C57BL/6J mice. In the fed condition, mice that consumed high-fat (HF, 45% fat) chow for 98 ± 5 days had elevated (P < 0.05) body fat percentage (DEXA), serum leptin (ELISA), HR and BP (72-h biotelemetry), and lower (P < 0.05) heat production and VO(2) (72-h metabolic chamber) versus animals that consumed standard chow (CON, 10% fat; n = 16 per group). HR, BP, VO(2), heat production and serum leptin decreased (all P < 0.05) in response to a 16-h fast (16:00-08:00 h) in both groups. Although the overall fold changes in cardiovascular and metabolic parameters were similar in magnitude among animals, fasting-induced reductions in cardiovascular and metabolic variables occurred ∼4 and ∼7 h earlier (P < 0.05), respectively, in HF versus CON mice. These findings indicate that while metabolic and cardiovascular stress evoked by a 16-h fast at 22°C is not different between HF and CON mice, fasting-induced responses occur sooner in obese animals.
Collapse
Affiliation(s)
- Jason M Tanner
- College of Health, University of Utah, Salt Lake City, UT 84132, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Conti B, Sanchez-Alavez M, Winsky-Sommerer R, Morale MC, Lucero J, Brownell S, Fabre V, Huitron-Resendiz S, Henriksen S, Zorrilla EP, de Lecea L, Bartfai T. Transgenic mice with a reduced core body temperature have an increased life span. Science 2006; 314:825-8. [PMID: 17082459 DOI: 10.1126/science.1132191] [Citation(s) in RCA: 274] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Reduction of core body temperature has been proposed to contribute to the increased life span and the antiaging effects conferred by calorie restriction (CR). Validation of this hypothesis has been difficult in homeotherms, primarily due to a lack of experimental models. We report that transgenic mice engineered to overexpress the uncoupling protein 2 in hypocretin neurons (Hcrt-UCP2) have elevated hypothalamic temperature. The effects of local temperature elevation on the central thermostat resulted in a 0.3 degrees to 0.5 degrees C reduction of the core body temperature. Fed ad libitum, Hcrt-UCP2 transgenic mice had the same caloric intake as their wild-type littermates but had increased energy efficiency and a greater median life span (12% increase in males; 20% increase in females). Thus, modest, sustained reduction of core body temperature prolonged life span independent of altered diet or CR.
Collapse
Affiliation(s)
- Bruno Conti
- Harold L. Dorris Neurological Research Center, Scripps Research Institute, La Jolla, CA 92037, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Stuart JA, Brown MF. Energy, quiescence and the cellular basis of animal life spans. Comp Biochem Physiol A Mol Integr Physiol 2006; 143:12-23. [PMID: 16377223 DOI: 10.1016/j.cbpa.2005.11.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 11/02/2005] [Accepted: 11/03/2005] [Indexed: 01/11/2023]
Abstract
Animals are routinely faced with harsh environmental conditions in which insufficient energy is available to grow and reproduce. Many animals adapt to this challenge by entering a dormant, or quiescent state. In some animals, such as the nematode Caenorhabditis elegans, quiescence is coincident with increased stress resistance and longevity. Here we review evidence that the rules of life span extension established in C. elegans may be generally true of most animals. That is, that the rate of animal aging correlates inversely with cellular resistance to physiological stress, particularly oxidative stress, and that stress resistance is co-regulated with the quiescence adaptation (where the latter occurs). We discuss evidence for highly conserved intracellular signalling pathways involved in energy sensing that are sensitive to aspects of mitochondrial energy transduction and can be modulated in response to energetic flux. We provide a broad overview of the current knowledge of the relationships between energy, metabolism and life span.
Collapse
Affiliation(s)
- Jeffrey A Stuart
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada L2S 3A1.
| | | |
Collapse
|
23
|
Hsieh EA, Chai CM, Hellerstein MK. Effects of caloric restriction on cell proliferation in several tissues in mice: role of intermittent feeding. Am J Physiol Endocrinol Metab 2005; 288:E965-72. [PMID: 15613681 DOI: 10.1152/ajpendo.00368.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reduced cell proliferation may mediate anticarcinogenic effects of caloric restriction (CR). Using heavy water (2H2O) labeling, we investigated the cell proliferation response to CR in detail, including time course, effect of refeeding, and role of intermittent feeding with 5% CR. In the time-course study, 8-wk-old female C57BL/6J mice were placed on a 33% CR regimen (fed 3 times/wk) for varying durations. Compared with responses in controls fed ad libitum (AL), proliferation rates of keratinocytes, mammary epithelial cells, and T cells were markedly reduced within 2 wk of CR. In mice fed 95% ad libitum (C95, fed 3 times/wk), cell proliferation was also reduced in all tissues so that differences from 33% CR were only significant at 1 mo. In the refeeding study, mice were refed a C95 diet for varying durations after 1 mo of 33% CR. Cell proliferation rebounded to a suprabasal rate in all tissues after 2 wk of refeeding and then normalized after 2 mo, although the C95 group again exhibited lower cell proliferation than the AL group. The role of intermittent feeding was studied by comparing 33% CR and C95 animals (both fed intermittently) with animals fed isocalorically either daily or continuously by pellet dispenser. Intermittent feeding had no additive effect on 33% CR but reduced cell proliferation in all tissues at the 95% caloric intake level. In summary, the CR effect on cell proliferation is potent, rapid, and reversible in several tissues, and an intermittent feeding pattern reproduces much of the effect in the absence of substantial CR.
Collapse
Affiliation(s)
- Elaine A Hsieh
- Department of Nutritional Sciences and Toxicology, Morgan Hall, Rm. 309, University of California, Berkeley, CA 94720, USA
| | | | | |
Collapse
|
24
|
Higami Y, Yamaza H, Shimokawa I. Laboratory Findings of Caloric Restriction in Rodents and Primates. Adv Clin Chem 2005; 39:211-37. [PMID: 16013673 DOI: 10.1016/s0065-2423(04)39008-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yoshikazu Higami
- Department of Pathology and Gerontology, Nagasaki University Graduate School of Biomedical Science, Nagasaki 852-8523, Japan
| | | | | |
Collapse
|
25
|
Koizumi A. Snap shots of Dr Roy Walford as an active scientist and a guiding mentor. Exp Gerontol 2004. [DOI: 10.1016/j.exger.2004.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
26
|
Abe J, Okazawa M, Adachi R, Matsumura K, Kobayashi S. Primary cold-sensitive neurons in acutely dissociated cells of rat hypothalamus. Neurosci Lett 2003; 342:29-32. [PMID: 12727310 DOI: 10.1016/s0304-3940(03)00239-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Local warming or cooling of the preoptic and anterior hypothalamus (PO/AH) areas evokes various thermoregulatory responses in mammals. We have hypothesized that warm- and cold-sensitive neurons recorded in the PO/AH are multiple thermostats that regulate the core temperature against heat and cold, respectively. However, since the proportion of cold-sensitive neurons is low, it is still controversial whether primary cold-sensitive neurons exist in the PO/AH. To answer this question, we investigated cold-sensitive neurons with Ca(2+) imaging in acutely dissociated PO/AH cells. Their threshold temperatures were 27.3+/-0.44 degrees C (mean+/-SEM, n=55). In extracellular recordings cooling evoked discharges in these cold-sensitive neurons. We conclude that primary cold-sensitive neurons with low threshold temperatures exist in PO/AH.
Collapse
Affiliation(s)
- Junji Abe
- Division of Biological Information, Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, 606-8501, Kyoto, Japan
| | | | | | | | | |
Collapse
|
27
|
Wada Y, Kayo T, Koizumi A. Characterization of gene expression profile associated with energy restriction-induced cold tolerance of heart. Microsc Res Tech 2002; 59:313-6. [PMID: 12424794 DOI: 10.1002/jemt.10210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hypothermia is known to be a common feature of energy restriction (ER) and essential for a life-prolonging effect of ER. The heart is sensitive to hypothermia, but the heart in ER mice acquires some adaptation to hypothermia. The aim of the present study was to characterize the gene expression profile associated with ER-induced cold resistance of heart. We analyzed the expression of heart mRNA from ER (200 kJ/week) or control (400 kJ/week) B6 11-month-old male mice using cDNA array membranes including 588 genes. Eighty-eight out of 588 genes were expressed in the heart. mRNAs increased by ER were glutathion S-transferase Mu1, transcriptional factor 1 for heat shock gene (HSF1), and fetal myosin alkali light chain genes. mRNA decreased by ER were seven genes in four categories: (1). cell cycle or apoptosis-related proteins (cyclin G and nucleoside diphosphate kinase B); (2). stress response proteins (oxidative stress-induced protein); (3). DNA repair proteins (protein involved in DNA double-strand break repair, Rad23 UV excision repair protein homologue and ubiquitin-conjugating enzyme); and (4). cell-surface antigens (lamimin receptor 1). These data suggest that the heart of ER mice adapts to hypothermia involving heat shock proteins and their transcriptional factors and by changing structure and property of myofibrils. It is also suggested that ER induces protection against oxidative stress and inhibits cell proliferation of "nonmuscle cells" in the heart. Gene expression analysis using cDNA array was useful for screening genes associated with ER-induced cold adaptation.
Collapse
Affiliation(s)
- Yasuhiko Wada
- Department of Hygiene, Hyogo College of Medicine, Nishinomiya, 663-8501, Japan.
| | | | | |
Collapse
|
28
|
Williams TD, Chambers JB, Henderson RP, Rashotte ME, Overton JM. Cardiovascular responses to caloric restriction and thermoneutrality in C57BL/6J mice. Am J Physiol Regul Integr Comp Physiol 2002; 282:R1459-67. [PMID: 11959690 DOI: 10.1152/ajpregu.00612.2001] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We utilized variations in caloric availability and ambient temperature (T(a)) to examine interrelationships between energy expenditure and cardiovascular function in mice. Male C57BL/6J mice (n = 6) were implanted with telemetry devices and housed in metabolic chambers for measurement of mean arterial pressure (MAP), heart rate (HR), O(2) consumption (VO(2)), and locomotor activity. Fasting (T(a) = 23 degrees C), initiated at the onset of the dark phase, resulted in large and transient depressions in MAP, HR, VO(2), and locomotor activity that occurred during hours 6-17, which suggests torporlike episodes. Food restriction (14 days, 60% of baseline intake) at T(a) = 23 degrees C resulted in progressive reductions in MAP and HR across days that were coupled with an increasing occurrence of episodic torporlike reductions in HR (<300 beats/min) and VO(2) (<1.0 ml/min). Exposure to thermoneutrality (T(a) = 30 degrees C, n = 6) reduced baseline light-period MAP (-14 +/- 2 mmHg) and HR (-184 +/- 12 beats/min). Caloric restriction at thermoneutrality produced further reductions in MAP and HR, but indications of torporlike episodes were absent. The results reveal that mice exhibit robust cardiovascular responses to both acute and chronic negative energy balance. Furthermore, we conclude that T(a) is a very important consideration when assessing cardiovascular function in mice.
Collapse
Affiliation(s)
- T D Williams
- Department of Nutrition, Food, and Exercise Sciences, Florida State University, Tallahassee, Florida 32306-4340, USA
| | | | | | | | | |
Collapse
|
29
|
Affiliation(s)
- R Weindruch
- Department of Medicine and Veterans Affairs Geriatric Research, Education, and Clinical Center, University of Wisconsin, Madison 53705, USA
| | | |
Collapse
|
30
|
Wada Y, Shinbo A, Tsukada M, Iijima T, Koizumi A. Electrophysiological evidence of an increase in cold tolerance of cardiac muscles in mice after energy restriction. Mech Ageing Dev 1997; 97:35-43. [PMID: 9223124 DOI: 10.1016/s0047-6374(97)01898-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Life-prolonging energy restriction (ER) has been known to extend longevity. The heart was selected as the target organ of ER and the electrophysiological properties of ER on the heart were investigated. Action potential parameters were measured on ventricular papillary muscles of C57BL/6 mice (2-6 months of age). Resting membrane potential (Rm) did not change even when the temperature was lowered to 20 degrees C in ER mice (-67.5 +/- 0.8 mV), however, the membrane was depolarized in the control (-61.1 +/- 1.1 mV). Action potential duration measured at 30 and 50% repolarization was significantly prolonged in ER mice at 20-35 degrees C. Ouabain (10 microM) decreased Rm in ER mice at 20 degrees C (-68.6 +/- 1.0 to -63.6 +/- 0.8 mV), but failed to decrease Rm in the control (-60.6 +/- 1.8 to -62.1 +/- 1.2 mV). There were no significant differences in extracted Na, K-ATPase activity or affinity and binding capacity of ouabain between ER and control hearts. These results indicate that in ER mice the lack of effect of temperature on Rm was not due to a change in the physicochemical properties of Na, K-ATPase. The present study collectively suggests that ER increases cold tolerance in the heart of mice.
Collapse
Affiliation(s)
- Y Wada
- Department of Hygiene, Akita University School of Medicine, Japan
| | | | | | | | | |
Collapse
|
31
|
Koizumi A, Wada Y, Tuskada M, Kayo T, Naruse M, Horiuchi K, Mogi T, Yoshioka M, Sasaki M, Miyamaura Y, Abe T, Ohtomo K, Walford RL. A tumor preventive effect of dietary restriction is antagonized by a high housing temperature through deprivation of torpor. Mech Ageing Dev 1996; 92:67-82. [PMID: 9032756 DOI: 10.1016/s0047-6374(96)01803-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Energy restriction (ER) has proven to be the only effective means of retarding aging in mice. The mechanisms of multiplicity of effects of ER on aging remain, however, fragmentary. ER induces daily torpor, the induction of which is reduced by increasing the ambient temperature to 30 degrees C. The effects of preventing hypothermia in ER animals were studied in terms of the expected consequences of ER on survival, disease pattern and a number of physiological parameters in autoimmune prone MRL/lpr mice and lymphoma prone C57BL, 6 mice. The results demonstrate that torpor plays a crucial role in the prevention of lymphoma development but does not have an affect on other aspects of ER, such as prevention of autoimmune diseases.
Collapse
Affiliation(s)
- A Koizumi
- Department of Hygiene, Akita University School of Medicine, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Reed MJ, Penn PE, Li Y, Birnbaum R, Vernon RB, Johnson TS, Pendergrass WR, Sage EH, Abrass IB, Wolf NS. Enhanced cell proliferation and biosynthesis mediate improved wound repair in refed, caloric-restricted mice. Mech Ageing Dev 1996; 89:21-43. [PMID: 8819104 DOI: 10.1016/0047-6374(96)01737-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Aged mice that have undergone long-term caloric-restriction (CR) have improved health and enhanced longevity in comparison to aged mice that are ad libitum-fed (AL). However, caloric-restriction does not benefit the impaired wound healing of aged mice. To test the hypothesis that CR mice have the capacity for enhanced wound repair, but require a short-term period of additional nutrient intake to show this advantage, we assessed wound healing in CR mice that had been refed (RF) an ad libitum diet for 4 weeks prior to wounding. Two strains of AL young (Y AL) (4-6 months), AL middle-aged (M AL) (15-17 months), and three different, matched cohorts of old mice (O) (30-33 months): O AL, O CR, and O RF were studied. Two full-thickness 4 mm diameter punch biopsy skin wounds were created on the dorsum of each mouse. Animals were sacrificed and wounds were harvested at 1,2,3,5, and 7 days post-wounding. Repair of wounds was slower in O AL and O CR mice compared to Y AL and M AL animals. In contrast, the O RF mice healed similarly to that of the Y AL and M AL mice, as assessed by measures of wound area and histologic criteria. O RF mice demonstrated enhanced synthesis of type I collagen mRNA in comparison to O AL and O CR mice. A greater number of endothelial cells and fibroblasts at the wound edge of the O RF mice exhibited replication in vivo as measured by uptake of BrdU. O RF mice had higher levels of insulin-like binding protein 3 (IGFBP-3). Furthermore, fibroblasts derived from the explant of the punch biopsy of O CR mouse skin revealed enhanced proliferation and contraction in vitro, in comparison to fibroblasts from the O AL mice. In conclusion, O RF mice demonstrate an enhanced capacity to undergo wound repair in comparison to O AL mice. This effect appears to be mediated, in part, by enhanced cell proliferation, contraction, and collagen biosynthesis. In addition, short-term refeeding induced an increase in the serum level of IGFBP-3, the major binding protein for IGF-1. These data confirm that cells from O CR animals have a preserved proliferative, biosynthetic, and contractile capacity, but that an adequate source of nutrients is necessary to demonstrate this advantage in wound healing.
Collapse
Affiliation(s)
- M J Reed
- Department of Medicine, University of Washington, Seattle 98195, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Under normal physiological conditions, the use of oxygen by cells of aerobic organisms generates potentially deleterious reactive oxygen metabolites. A chronic state of oxidative stress exists in cells because of an imbalance between prooxidants and antioxidants. The amount of oxidative damage increases as an organism ages and is postulated to be a major causal factor of senescence. Support for this hypothesis includes the following observations: (i) Overexpression of antioxidative enzymes retards the age-related accrual of oxidative damage and extends the maximum life-span of transgenic Drosophila melanogaster. (ii) Variations in longevity among different species inversely correlate with the rates of mitochondrial generation of the superoxide anion radical (O2) and hydrogen peroxide. (iii) Restriction of caloric intake lowers steady-state levels of oxidative stress and damage, retards age-associated changes, and extends the maximum life-span in mammals.
Collapse
Affiliation(s)
- R S Sohal
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
| | | |
Collapse
|
34
|
Abstract
This paper investigates similarities in physiological senescent changes in various mammalian organ systems and relates these to postulated mechanisms of age modulation. It proposes that the observed decline in homeostasis with age is due to an inability of target cells, of neural, endocrine and other forms of control, to upregulate after their downregulation. The well-documented flattening of circadian rhythms with age, particularly the loss of the sustained diurnal hypothermic phase, is described as integral to such change, and maintenance or induction of certain youthful circadian patterns is proposed as a means of restoring homeostasis in senescence and other conditions.
Collapse
Affiliation(s)
- M F MacGibbon
- Department of Veterinary Pathology, University of Sydney, NSW, Australia
| |
Collapse
|
35
|
Tillman JB, Dhahbi JM, Mote PL, Walford RL, Spindler SR. Dietary calorie restriction in mice induces carbamyl phosphate synthetase I gene transcription tissue specifically. J Biol Chem 1996; 271:3500-6. [PMID: 8631954 DOI: 10.1074/jbc.271.7.3500] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Dietary calorie restriction (CR) delays age-related physiologic changes, increases maximum life span, and reduces cancer incidence. Here, we present the novel finding that chronic reduction of dietary calories by 50% without changing the intake of dietary protein induced the activity of mouse hepatic carbamyl phosphate synthetase I (CpsI) 5-fold. In liver, CpsI protein, mRNA, and gene transcription were each stimulated by approximately 3-fold. Thus, CR increased both the rate of gene transcription and the specific activity of the enzyme. Short-term feeding studies demonstrated that higher cpsI expression was due to CR and not consumption of more dietary protein. Intestinal CpsI activity was stimulated 2-fold, while its mRNA level did not change, suggesting enzyme activity or translation efficiency was stimulated. CpsI catalyzes the conversion of metabolic ammonia to carbamyl phosphate, the rate-limiting step in urea biosynthesis. cpsI induction suggests there is a shift in the metabolism of calorie-restricted animals toward protein catabolism. CpsI induction likely facilitates metabolic detoxification of ammonia, a strong neurotoxin. Enhanced protein turnover and metabolic detoxification may extend life span. Physiologic similarities between calorie-restricted and hibernating animals suggest the effects of CR may be part of a spectrum of adaptive responses that include hibernation.
Collapse
Affiliation(s)
- J B Tillman
- Department of Biochemistry, University of California, Riverside, California 92521, USA
| | | | | | | | | |
Collapse
|
36
|
Holloway JC, Geiser F. Influence of torpor on daily energy expenditure of the dasyurid marsupial Sminthopsis crassicaudata. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART A, PHYSIOLOGY 1995; 112:59-66. [PMID: 7553337 DOI: 10.1016/0300-9629(95)00089-p] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Daily torpor is an energy-conserving mechanism, used by many small marsupials to reduce energy expenditure during adverse environmental conditions. Since little is known about how much energy is actually saved by torpor in marsupials and how this is related to the duration of torpor bouts, we investigated the effect of ambient temperature (Ta) on different metabolic states and the effect of torpor bout duration in Sminthopsis crassicaudata (16 g) on average daily metabolic rate (ADMR). Ta had a significant effect on the active and resting metabolic rates (MR), both being higher at Ta 12 degrees C than Ta 18 degrees C (P < 0.001, t-test). In contrast, the ADMR at Ta 12 degrees C and Ta 18 degrees C did not differ significantly, and it appears that the increased cost for thermoregulation in normothermic active and resting animals at Ta 12 degrees C was compensated by a decrease in MR during torpor. Torpor bout duration was negatively correlated with ADMR. Torpor bouts of 5 hr reduced ADMR by 12-16%. Torpor bouts of more than 10 hr reduced ADMRs by 30-50%. Our study shows that torpor can significantly reduce daily energy expenditure in S. crassicaudata, and this may be important for the survival of this species in the wild.
Collapse
Affiliation(s)
- J C Holloway
- Department of Zoology, University of New England, Armidale NSW, Australia
| | | |
Collapse
|
37
|
Weindruch R, May PC. Use of caloric restriction to investigate neuroendocrine involvement in aging. Neurobiol Aging 1995; 16:845-7; discussion 855-6. [PMID: 8532120 DOI: 10.1016/0197-4580(95)00067-o] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- R Weindruch
- Department of Medicine and VA Geriatric Research, Education and Clinical Center, University of Wisconsin, Madison 53706, USA
| | | |
Collapse
|
38
|
Hursting SD, Perkins SN, Phang JM. Calorie restriction delays spontaneous tumorigenesis in p53-knockout transgenic mice. Proc Natl Acad Sci U S A 1994; 91:7036-40. [PMID: 8041741 PMCID: PMC44333 DOI: 10.1073/pnas.91.15.7036] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Transgenic mice with both alleles of the p53 tumor suppressor gene (frequently mutated in human tumors) knocked out by gene targeting provide a potentially useful tumorigenesis model because these mice rapidly develop spontaneous tumors. To determine whether tumorigenesis in p53-knockout mice is sensitive to experimental manipulation, tumor development in response to calorie restriction (CR; a potent inhibitor of rodent tumors) was evaluated. Tumor development was monitored for 48 weeks in male nullizygous p53-knockout and wild-type littermate mice (28-30 per treatment group) fed ad libitum (AL) or restricted to 60% of AL carbohydrate calorie intake. CR:p53-knockout mice (median survival = 25 weeks) experienced a delay in tumor onset and subsequent mortality (P = 0.0002) relative to AL:p53-knockout mice (median survival = 16 weeks). Tumor development and mortality in wild-type littermates on either diet treatment were < 4% through 48 weeks. Cell cycle analyses were performed on splenocytes from p53-knockout mice and wild-type littermates after 4 weeks of AL feeding or CR (5 per group). The percentage of splenocytes in S phase of the cell cycle was 3-fold higher for p53-knockout mice than wild-type mice (P < 0.001), and CR reduced the percentage of S-phase splenocytes in both p53-knockout and wild-type mice (P = 0.012). These data demonstrate that tumor development in p53-knockout mice genetically predisposed to tumors can be delayed by CR (possibly via cell cycle modulation) and suggest that these mice provide a very useful model of spontaneous tumorigenesis.
Collapse
Affiliation(s)
- S D Hursting
- Laboratory of Nutritional and Molecular Regulation, National Cancer Institute-Frederick Cancer Research and Development Center, MD 21702
| | | | | |
Collapse
|
39
|
Jin YH, Koizumi A. Decreased cellular proliferation by energy restriction is recovered by increasing housing temperature in rats. Mech Ageing Dev 1994; 75:59-67. [PMID: 9128754 DOI: 10.1016/0047-6374(94)90028-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the effects of life-prolonging energy restriction (ER) on body temperature (BT) and cellular proliferation in rats. Animals were fed either a control diet (C: 220 kJ/day) or an ER diet (110 kJ/day) from 7 weeks of age, and were housed at 20-22 degrees C. Another group of animals, fed on the ER diet, were transferred from 20-22 degrees C to a room at 30 degrees C (ER + I) at 20 weeks of age. The core body temperatures in individual animals were recorded over a 3-day period between 20 and 24 weeks of age. Cellular proliferation rates were quantitated by labeling S phase cells in the jejunum, epidermis, pituitary, and lung with bromodeoxy-uridine at 24 weeks of age. Long-term ER reduced the mean BT by 1 degree C, and reduced cellular proliferation in the jejunum, epidermis, pituitary, and lung. At 30 degrees C, the inhibitions were partially lifted in the examined organs except in the pituitary. Therefore, decreased cellular proliferation in the various organs after long-term ER in rats is lifted as it is in mice.
Collapse
Affiliation(s)
- Y H Jin
- Department of Hygiene, Akita University School of Medicine, Japan
| | | |
Collapse
|
40
|
Kramer K, van Acker SA, Voss HP, Grimbergen JA, van der Vijgh WJ, Bast A. Use of telemetry to record electrocardiogram and heart rate in freely moving mice. J Pharmacol Toxicol Methods 1993; 30:209-15. [PMID: 8123902 DOI: 10.1016/1056-8719(93)90019-b] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This paper describes for the first time the possibility to record the electrocardiogram (ECG) and heart rate (HR) with a commercially available telemetry and data acquisition system in freely moving mice. The system comprises a telemetry transmitter implanted in the peritoneal cavity and a receiver, placed underneath the home cage, an A/D converter (MacLab) and a Macintosh LC II 4/80 computer with software (MacLab, Chart/Scope). The raw analog ECG data are digitized within the MacLab and can be converted to HR data additionally. The effects of surgery for implanting the transmitter, handling and anesthesia by either Nembutal or a mixture of Hypnorm, Dormicum, and water, on the changes in ECG and HR were examined. The telemetry system for recording the ECG and HR provides an accurate and reliable method for monitoring the direct effects of handling on HR. By using this telemetry system, we maintain that measurements in freely moving animals are more efficient, reliable, and less labor-intensive than the measurement techniques described in the literature thus far.
Collapse
Affiliation(s)
- K Kramer
- Faculty of Chemistry, Department of Pharmacochemistry, Free University, Amsterdam, The Netherlands
| | | | | | | | | | | |
Collapse
|
41
|
Tsukada M, Hamade N, Wada Y, Mogi T, Kamiyama S, Koizumi A. Energy restriction suppresses microsomal Ca(2+)-ATPase activities in various organs in C57BL/6 female mice in both euthermic and torpor states. Mech Ageing Dev 1993; 68:183-9. [PMID: 8350658 DOI: 10.1016/0047-6374(93)90150-p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
C57BL/6 female mice were fed a daily control diet (n = 5, 3.9 g/day, 95 kcal/week) or ER diet (n = 5, 2.3 g/day, 48 kcal/week) at 1800 h from 6 weeks of age. Telemetry, conducted at 6 months of age, confirmed that all ER mice entered daily torpor (core body temperature less than 31 degrees C) for 6.63 +/- 2.34 h/day while control mice were euthermic (> 35 degrees C). In vitro activities of microsomal Ca(2+)-ATPase were determined in the brain, liver, salivary gland and kidney from these mice at 6 months of age. Assays were performed at three incubation temperatures of 37 degrees C, 31 degrees C and 25 degrees C. In assays at 37 degrees C, the activities of Ca(2+)-ATPase in the brain and salivary gland from ER mice were lower than those in corresponding organs from control mice. The suppression became profound as the incubation temperature decreased. On the other hand, at 37 degrees C Ca(2+)-ATPase activities in the liver and kidney from ER mice were not lower than those in corresponding organs from control mice, but decreased significantly at low temperatures. Microsomal Ca(2+)-ATPase activities thus appeared to be reduced in ER mice, although it remains unknown whether the present results represent reduced in vivo capacities to regulate cytosolic Ca2+ concentrations.
Collapse
Affiliation(s)
- M Tsukada
- Department of Hygiene, Akita University School of Medicine, Japan
| | | | | | | | | | | |
Collapse
|
42
|
Miyamura Y, Tawa R, Koizumi A, Uehara Y, Kurishita A, Sakurai H, Kamiyama S, Ono T. Effects of energy restriction on age-associated changes of DNA methylation in mouse liver. Mutat Res 1993; 295:63-9. [PMID: 7680421 DOI: 10.1016/0921-8734(93)90002-k] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
DNA methylation is known to change with age in several mammalian species. Here we have examined the effect of dietary energy restriction on this age-associated change in liver DNA of C3H/SHN mice. The total 5-methyldeoxycytidine level in the genome decreased slightly soon after energy restriction started. The effect, however, diminished with time and no appreciable difference was detected at middle and old ages. The degree of methylation at the c-myc gene, on the other hand, was not affected by energy restriction at early periods, but the age-dependent alterations at later ages were repressed. This is a new finding to show that DNA methylation is one of the molecular indices of aging affected by energy restriction. It suggests an importance of DNA methylation in the aging process.
Collapse
Affiliation(s)
- Y Miyamura
- Department of Radiation Research, Tohoku University School of Medicine, Sendai, Japan
| | | | | | | | | | | | | | | |
Collapse
|
43
|
|
44
|
Hamade N, Jin Y, Tsukada M, Wada Y, Koizumi A. O,O,S-Trimethyl phosphorothioate induces hypothermia in Fischer 344 rats in a manner dependent on both doses and housing temperatures. Arch Toxicol 1993; 67:72-5. [PMID: 8452484 DOI: 10.1007/bf02072039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We explored the effects of O,O,S-trimethyl phosphorothioate (OOS-TMP) on body temperatures in Fischer 344 female rats. The 7-day LD50 p.o. for Fischer 344 female rats was found to be 11.8 mg/kg. OOS-TMP induced long-lasting (more than 48 h) and extensive hypothermia at doses > or = 14 mg/kg at a typical laboratory temperature (22 degrees C) while it produced typical symptoms at 10 mg/kg without hypothermia. In contrast, pair-fed (to 20 mg/kg rats) rats (n = 4) did not become hypothermic, negating any role of hypophagia in OOS-TMP associated hypothermia. We next investigated the effects of housing temperatures on toxicities at a LD50 dose (12 mg/kg). At 30 degrees C (n = 11) and 22 degrees C (n = 13), rats did not have hypothermic bouts but at 15 degrees C, eight out of ten rats had. Evidence that changes of housing temperatures neither modified clinical symptoms nor changed mortality rates discards a possibility of hypothermia being involved in delayed toxicity. A novel result of the present study suggests that thermoregulation may be heavily impaired by a special class of organophosphorus compounds.
Collapse
Affiliation(s)
- N Hamade
- Department of Hygiene, Akita University School of Medicine, Japan
| | | | | | | | | |
Collapse
|