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Nascimento RHDO, Pejon TMM, Beck WR. Moderate caloric restriction improved body composition and maintains bone quality of rats under hypoestrogenism. Obes Res Clin Pract 2025; 19:163-170. [PMID: 40251096 DOI: 10.1016/j.orcp.2025.04.002] [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: 08/13/2024] [Revised: 04/01/2025] [Accepted: 04/04/2025] [Indexed: 04/20/2025]
Abstract
BACKGROUND Hypoestrogenism state is associated with weight and adiposity gain, generally impairing bone properties. Caloric restriction (CR) is the main intervention to promote weight loss, however, a chronic severe restriction can lead to bone loss and malnutrition. OBJECTIVE To analyse whether 12 weeks of moderate CR could reduce body mass and adiposity without worsening the bone health of ovariectomized (OVX) rats. METHODS CR and OVX-CR animals were subject daily to receive a 20 % less amount of food based on the last week's consumption of C and OVX groups. Body mass and food intake were recorded weekly, and spontaneous physical activity (SPA) biweekly. The adipose tissue of subcutaneous (SAT), peritoneal (PTAT), and perigonadal (PGAT) portions was collected to record its mass, and the right femur was collected to determine bone volume (BV), density (BD), mineral density (BMD), and percentage of mineral material (MM). RESULTS Ovariectomy increased body mass and food intake (p < 0.001), SAT, PTAT, and PGAT mass (p < 0.01), decreased BV (p < 0.05), BD and BMD (p < 0.01) and MM (p < 0.05), but not affected SPA (p = 0.16). CR decreased body mass, SAT, PTAT, and PGAT mass (p < 0.01) and BMD and MM (p < 0.05), but did not affect BV (p = 0.90), BD (p = 0.24), and SPA (p = 0.25). Therefore, post-hoc data did not demonstrate significant differences in these bone parameters between the OVX and OVX-RC groups (p > 0.05). CONCLUSION 12 weeks of 20 % of CR is enough to prevent weight and fat gain in the hypoestrogenism state without causing additional worsening in bone properties.
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Affiliation(s)
- Rafael Henrique de Oliveira Nascimento
- Laboratory of Endocrine Physiology and Physical Exercise, Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil
| | - Taciane Maria Melges Pejon
- Laboratory of Endocrine Physiology and Physical Exercise, Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil
| | - Wladimir Rafael Beck
- Laboratory of Endocrine Physiology and Physical Exercise, Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil.
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Resistance training prevents dynamics and mitochondrial respiratory dysfunction in vastus lateralis muscle of ovariectomized rats. Exp Gerontol 2023; 173:112081. [PMID: 36608776 DOI: 10.1016/j.exger.2023.112081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023]
Abstract
To investigate whether ovariectomy affects mitochondrial respiratory function, gene expression of the biogenesis markers and mitochondrial dynamics of the vastus lateralis muscle, female Wistar rats divided into ovariectomized (OVX) and intact (INT) groups were kept sedentary (SED) or submitted to resistance training (RT) performed for thirteen weeks on a vertical ladder in which animals climbed with a workload apparatus. RT sessions were performed with four climbs with 65, 85, 95, and 100 % of the rat's previous maximum workload. Mitochondrial Respiratory Function data were obtained by High-resolution respirometry. Gene expression of FIS1, MFN1 and PGC1-α was evaluated by real-time PCR. There was a decrease on oxidative phosphorylation capacity in OVX-SED compared to other groups. Trained groups presented increase on oxidative phosphorylation capacity when compared to sedentary groups. For respiratory control ratio (RCR), OVX-SED presented lower values when compared to INT-SED and to trained groups. Trained groups presented RCR values higher compared to INT-SED. Exercise increased the values of FIS1, MFN1 and PGC1-α expression compared to OVX-SED. Our results demonstrated that in the absence of ovarian hormones, there is a great decrease in oxidative phosphorylation and electron transfer system capacities of sedentary animals. RT was able to increase the expression of genes related to mitochondrial dynamics markers, reversing the condition determined by ovariectomy.
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Kelley RC, Betancourt L, Noriega AM, Brinson SC, Curbelo-Bermudez N, Hahn D, Kumar RA, Balazic E, Muscato DR, Ryan TE, van der Pijl RJ, Shen S, Ottenheijm CAC, Ferreira LF. Skeletal myopathy in a rat model of postmenopausal heart failure with preserved ejection fraction. J Appl Physiol (1985) 2022; 132:106-125. [PMID: 34792407 PMCID: PMC8742741 DOI: 10.1152/japplphysiol.00170.2021] [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: 03/15/2021] [Revised: 11/01/2021] [Accepted: 11/11/2021] [Indexed: 01/03/2023] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) accounts for ∼50% of all patients with heart failure and frequently affects postmenopausal women. The HFpEF condition is phenotype-specific, with skeletal myopathy that is crucial for disease development and progression. However, most of the current preclinical models of HFpEF have not addressed the postmenopausal phenotype. We sought to advance a rodent model of postmenopausal HFpEF and examine skeletal muscle abnormalities therein. Female, ovariectomized, spontaneously hypertensive rats (SHRs) were fed a high-fat, high-sucrose diet to induce HFpEF. Controls were female sham-operated Wistar-Kyoto rats on a lean diet. In a complementary, longer-term cohort, controls were female sham-operated SHRs on a lean diet to evaluate the effect of strain difference in the model. Our model developed key features of HFpEF that included increased body weight, glucose intolerance, hypertension, cardiac hypertrophy, diastolic dysfunction, exercise intolerance, and elevated plasma cytokines. In limb skeletal muscle, HFpEF decreased specific force by 15%-30% (P < 0.05) and maximal mitochondrial respiration by 40%-55% (P < 0.05), increased oxidized glutathione by approximately twofold (P < 0.05), and tended to increase mitochondrial H2O2 emission (P = 0.10). Muscle fiber cross-sectional area, markers of mitochondrial content, and indices of capillarity were not different between control and HFpEF in our short-term cohort. Overall, our preclinical model of postmenopausal HFpEF recapitulates several key features of the disease. This new model reveals contractile and mitochondrial dysfunction and redox imbalance that are potential contributors to abnormal metabolism, exercise intolerance, and diminished quality of life in patients with postmenopausal HFpEF.NEW & NOTEWORTHY Heart failure with preserved ejection fraction (HFpEF) is a condition with phenotype-specific features highly prevalent in postmenopausal women and skeletal myopathy contributing to disease development and progression. We advanced a rat model of postmenopausal HFpEF with key cardiovascular and systemic features of the disease. Our study shows that the skeletal myopathy of postmenopausal HFpEF includes loss of limb muscle-specific force independent of atrophy, mitochondrial dysfunction, and oxidized shift in redox balance.
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Affiliation(s)
- Rachel C Kelley
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Lauren Betancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Andrea M Noriega
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Suzanne C Brinson
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Nuria Curbelo-Bermudez
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Dongwoo Hahn
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Ravi A Kumar
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Eliza Balazic
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Derek R Muscato
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Robbert J van der Pijl
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona
- Department of Physiology, Amsterdam UMC, Amsterdam, The Netherlands
| | - Shengyi Shen
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona
| | - Coen A C Ottenheijm
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona
- Department of Physiology, Amsterdam UMC, Amsterdam, The Netherlands
| | - Leonardo F Ferreira
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
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Zheng W, Hengevoß J, Soukup ST, Kulling SE, Xie M, Diel P. An isoflavone enriched diet increases skeletal muscle adaptation in response to physical activity in ovariectomized rats. Mol Nutr Food Res 2017; 61. [PMID: 28497652 DOI: 10.1002/mnfr.201600843] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 04/25/2017] [Accepted: 05/02/2017] [Indexed: 11/08/2022]
Abstract
SCOPE This study was to investigate anabolic adaptation of skeletal muscle in response to an isoflavone (ISO) enriched diet, training and their combinations in ovariectomized (OVX) rats. METHODS AND RESULTS Female Wistar rats were sedentary, performed treadmill uphill running, received ISOs, or a combination of ISOs and running after ovariectomy. Body weight was increased by OVX. Both ISO and training treatment antagonized this increase. The weights of soleus and gastrocnemius muscles were increased only when training and ISOs were combined. In soleus muscle insulin-like growth factor (IGF)-1R, MyoD and Myogenin expressions were only up-regulated by training in Sham groups. However, a stimulation of IGF-1R and MyoD expression could be observed when ISOs and training were combined. In gastrocnemius muscle MyoD and Myogenin expressions were stimulated by either training or ISOs. Additive effects were detected when combining the two interventions. CONCLUSION Our results indicate that the combination of ISOs and exercise is more efficient in increasing relative skeletal muscle mass and the expression of molecular markers related to anabolic adaptation in the skeletal muscle of female rats.
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Affiliation(s)
- Wenya Zheng
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany
| | - Jonas Hengevoß
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany
| | - Sebastian T Soukup
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Karlsruhe, Germany
| | - Sabine E Kulling
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Karlsruhe, Germany
| | - Mingyong Xie
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Patrick Diel
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany
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Estrogen modulates exercise endurance along with mitochondrial uncoupling protein 3 downregulation in skeletal muscle of female mice. Biochem Biophys Res Commun 2016; 480:758-764. [DOI: 10.1016/j.bbrc.2016.10.129] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 10/28/2016] [Indexed: 11/17/2022]
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Fryhofer GW, Freedman BR, Hillin CD, Salka NS, Pardes AM, Weiss SN, Farber DC, Soslowsky LJ. Postinjury biomechanics of Achilles tendon vary by sex and hormone status. J Appl Physiol (1985) 2016; 121:1106-1114. [PMID: 27633741 DOI: 10.1152/japplphysiol.00620.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/12/2016] [Indexed: 12/11/2022] Open
Abstract
Achilles tendon ruptures are common injuries. Sex differences are present in mechanical properties of uninjured Achilles tendon, but it remains unknown if these differences extend to tendon healing. We hypothesized that ovariectomized females (OVX) and males would exhibit inferior postinjury tendon properties compared with females. Male, female, and OVX Sprague-Dawley rats (n = 32/group) underwent acclimation and treadmill training before blunt transection of the Achilles tendon midsubstance. Injured hindlimbs were immobilized for 1 wk, followed by gradual return to activity and assessment of active and passive hindlimb function. Animals were euthanized at 3 or 6 wk postinjury to assess tendon structure, mechanics, and composition. Passive ankle stiffness and range of motion were superior in females at 3 wk; however, by 6 wk, passive and active function were similar in males and females but remained inferior in OVX. At 6 wk, female tendons had greater normalized secant modulus, viscoelastic behavior, and laxity compared with males. Normalized secant modulus, cross-sectional area and tendon glycosaminoglycan composition were inferior in OVX compared with females at 6 wk. Total fatigue cycles until tendon failure were similar among groups. Postinjury muscle fiber size was better preserved in females compared with males, and females had greater collagen III at the tendon injury site compared with males at 6 wk. Despite male and female Achilles tendons withstanding similar durations of fatigue loading, early passive hindlimb function and tendon mechanical properties, including secant modulus, suggest superior healing in females. Ovarian hormone loss was associated with inferior Achilles tendon healing.
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Affiliation(s)
- George W Fryhofer
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Benjamin R Freedman
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cody D Hillin
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nabeel S Salka
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Adam M Pardes
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephanie N Weiss
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel C Farber
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Louis J Soslowsky
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
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Males have Inferior Achilles Tendon Material Properties Compared to Females in a Rodent Model. Ann Biomed Eng 2016; 44:2901-2910. [PMID: 27150673 DOI: 10.1007/s10439-016-1635-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/29/2016] [Indexed: 01/08/2023]
Abstract
The Achilles tendon is the most commonly ruptured tendon in the human body. Numerous studies have reported incidence of these injuries to be upwards of five times as common in men than women. Therefore, the objective of this study was to investigate the sex- and hormone-specific differences between Achilles tendon and muscle between female, ovariectomized female (ovarian hormone deficient), and male rats. Uninjured tissues were collected from all groups for mechanical, structural, and histological analysis. Our results showed that while cross-sectional area and failure load were increased in male tendons, female tendons exhibited superior tendon material properties and decreased muscle fiber size. Specifically, linear and dynamic moduli were increased while viscoelastic properties (e.g., hysteresis, percent relaxation) were decreased in female tendons, suggesting greater resistance to deformation under load and more efficient energy transfer, respectively. No differences were identified in tendon organization, cell shape, cellularity, or proteoglycan content. Additionally, no differences in muscle fiber type distribution were observed between groups. In conclusion, inferior tendon mechanical properties and increased muscle fiber size may explain the increased susceptibility for Achilles tendon injury observed clinically in men compared to women.
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Noguchi S, Putri SP, Lan EI, Laviña WA, Dempo Y, Bamba T, Liao JC, Fukusaki E. Quantitative target analysis and kinetic profiling of acyl-CoAs reveal the rate-limiting step in cyanobacterial 1-butanol production. Metabolomics 2016; 12:26. [PMID: 26766939 PMCID: PMC4700068 DOI: 10.1007/s11306-015-0940-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/13/2015] [Indexed: 11/10/2022]
Abstract
Cyanobacterial 1-butanol production is an important model system for direct conversion of CO2 to fuels and chemicals. Metabolically-engineered cyanobacteria introduced with a heterologous Coenzyme A (CoA)-dependent pathway modified from Clostridium species can convert atmospheric CO2 into 1-butanol. Efforts to optimize the 1-butanol pathway in Synechococcus elongatus PCC 7942 have focused on the improvement of the CoA-dependent pathway thus, probing the in vivo metabolic state of the CoA-dependent pathway is essential for identifying its limiting steps. In this study, we performed quantitative target analysis and kinetic profiling of acyl-CoAs in the CoA-dependent pathway by reversed phase ion-pair liquid chromatography-triple quadrupole mass spectrometry. Using 13C-labelled cyanobacterial cell extract as internal standard, measurement of the intracellular concentration of acyl-CoAs revealed that the reductive reaction of butanoyl-CoA to butanal is a possible rate-limiting step. In addition, improvement of the butanoyl-CoA to butanal reaction resulted in an increased rate of acetyl-CoA synthesis by possibly compensating for the limitation of free CoA species. We inferred that the efficient recycling of free CoA played a key role in enhancing the conversion of pyruvate to acetyl-CoA.
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Affiliation(s)
- Shingo Noguchi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Sastia P. Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Ethan I. Lan
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095 USA
| | - Walter A. Laviña
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Yudai Dempo
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Takeshi Bamba
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1Yamadaoka, Suita, Osaka 565-0871 Japan
| | - James C. Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095 USA
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1Yamadaoka, Suita, Osaka 565-0871 Japan
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Stunes AK, Westbroek I, Gordeladze JO, Gustafsson BI, Reseland JE, Syversen U. Systemic leptin administration in supraphysiological doses maintains bone mineral density and mechanical strength despite significant weight loss. Endocrinology 2012; 153:2245-53. [PMID: 22374968 DOI: 10.1210/en.2011-1848] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effects of leptin on bone are controversial. Although in vitro studies have shown that leptin stimulates osteoblast differentiation and mineralization and inhibits osteoclastogenesis, some rodent studies have shown that leptin administered centrally might result in decreased bone formation. In the present study we have investigated the skeletal effects of supraphysiological concentrations of leptin administered sc to rats. Female Fischer rats were given leptin 100 μg/d, 200 μg/d, or saline by continuous infusion for 9 wk. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry, bone microarchitecture was analyzed by micro-computed tomography, and biomechanical properties were tested by three-point bending experiments. At the end of the study, the body weight was significantly lower in rats receiving leptin compared with controls (-10.8% and -12.0% in low- and high-dose leptin groups, respectively). The high-dose leptin group also significantly lost weight compared with baseline. The plasma leptin concentration was 14- and 33-fold increased in the low- and high-dose groups, respectively. No significant differences in femoral BMD were observed. Whole-body BMD was significantly lower in the low-dose leptin group, whereas there was no difference between the high-dose leptin group and the control. Mechanical strength and microarchitecture were similar in the high-dose and the control group. The low-dose group, however, had decreased cortical volume in the femoral metaphysis, lowered bone strength, and altered moment of inertia. In conclusion, leptin given at very high doses maintains BMD, microarchitecture, and mechanical strength in female rats, despite a significant decrease in body weight.
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Affiliation(s)
- Astrid K Stunes
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
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Sex hormones differentially influence voluntary running activity, food intake and body weight in aging female and male rats. Eur J Appl Physiol 2011; 112:3007-18. [PMID: 22170012 DOI: 10.1007/s00421-011-2271-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 11/28/2011] [Indexed: 01/10/2023]
Abstract
The aim of this study was to examine the longer-term effects of reduced gonadal hormones on food intake, food efficiency, voluntary running activity and body weight in mature male and female rats, compared to age-matched controls. We hypothesized that hormonal effects would differ for rats that were not rapidly growing and our results are consistent with this hypothesis. 6-8 month male and female rats were divided into four groups: Female and male control groups and a female and male experimental group. Control groups were intact for 46 weeks. Experimental groups were intact during Phase I (16 weeks), ovariectomized or orchidectomized during Phase II (20 weeks), and received estrogen or testosterone hormone replacement therapy (HRT) during the final Phase III (10 weeks). Food intake and running distance were monitored daily and body weight was recorded weekly for 46 weeks. Contrary to findings for young and growing animals, we did not observe a (1) stabilization of food intake in female rats following OVX, (2) loss of body weight with ORX in males, or (3) complete restoration of running activity in ORX males given testosterone, compared to females given estrogen. Feeding efficiency was not affected by aging in females or males. Loss of estrogen increased energy intake whereas reduced testosterone in males resulted in a negative energy balance. Findings suggest variable hormonal effects for aging male/female rats.
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Abstract
One segment of the population that is particularly inclined to liver fat accumulation is postmenopausal women. Although nonalcoholic hepatic steatosis is more common in men than in women, after menopause there is a reversal in gender distribution. At the present time, weight loss and exercise are regarded as first line treatments for NAFLD in postmenopausal women, as it is the case for the management of metabolic syndrome. In recent years, there has been substantial evidence coming mostly from the use of the animal model, that indeed estrogens withdrawal is associated with modifications of molecular markers favouring the activity of metabolic pathways ultimately leading to liver fat accumulation. In addition, the use of the animal model has provided physiological and molecular evidence that exercise training provides estrogens-like protective effects on liver fat accumulation and its consequences. The purpose of the present paper is to present information relative to the development of a state of NAFLD resulting from the absence of estrogens and the role of exercise training, emphasizing on the contribution of the animal model on these issues.
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12
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NAFLD, Estrogens, and Physical Exercise: The Animal Model. J Nutr Metab 2011; 2012:914938. [PMID: 21845221 PMCID: PMC3154523 DOI: 10.1155/2012/914938] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 06/05/2011] [Indexed: 12/17/2022] Open
Abstract
One segment of the population that is particularly inclined to liver fat accumulation is postmenopausal women. Although nonalcoholic hepatic steatosis is more common in men than in women, after menopause there is a reversal in gender distribution. At the present time, weight loss and exercise are regarded as first line treatments for NAFLD in postmenopausal women, as it is the case for the management of metabolic syndrome. In recent years, there has been substantial evidence coming mostly from the use of the animal model, that indeed estrogens withdrawal is associated with modifications of molecular markers favouring the activity of metabolic pathways ultimately leading to liver fat accumulation. In addition, the use of the animal model has provided physiological and molecular evidence that exercise training provides estrogens-like protective effects on liver fat accumulation and its consequences. The purpose of the present paper is to present information relative to the development of a state of NAFLD resulting from the absence of estrogens and the role of exercise training, emphasizing on the contribution of the animal model on these issues.
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13
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Lara-García M, Alvarado M, Cuevas E, Cortés-sol A, Domínguez A, Tovar A, Pacheco P. The Effects of Castration and Hormone Replacement on the Cross-Sectional Area of Pubococcygeus Muscle Fibers in the Female Rat. Anat Rec (Hoboken) 2011; 294:1242-8. [DOI: 10.1002/ar.21414] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Accepted: 04/04/2011] [Indexed: 12/23/2022]
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14
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Gloy V, Langhans W, Hillebrand JJG, Geary N, Asarian L. Ovariectomy and overeating palatable, energy-dense food increase subcutaneous adipose tissue more than intra-abdominal adipose tissue in rats. Biol Sex Differ 2011; 2:6. [PMID: 21569336 PMCID: PMC3114698 DOI: 10.1186/2042-6410-2-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 05/11/2011] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Menopause is associated with increased adiposity, especially increased deposition of intra-abdominal (IA) adipose tissue (AT). This differs from common or 'dietary' obesity, i.e., obesity apparently due to environmentally stimulated overeating, in which IAAT and subcutaneous (S) AT increase in similar proportions. The effect of menopause on adiposity is thought to be due to the decreased secretion of ovarian estrogens. Ovariectomy in rats and other animals is a commonly used model of menopause. It is well known that ovariectomy increases adiposity and that this can be reversed by estradiol treatment, but whether ovariectomy selectively increases IAAT has not been measured directly. Therefore, we used micro-computed tomography (microCT) to investigate this question in both chow-fed and dietary-obese rats. METHODS Ovariectomized, ovariectomized and estradiol treated, and sham-operated (intact) rats were fed chow or chow plus Ensure (Abbott Nutrition; n = 7/group). Total (T) AT, IAAT and SAT were measured periodically by microCT. Regional distribution of AT was expressed as IAAT as a percentage of TAT (%IAAT). Excesses in these measures were calculated with respect to chow-fed intact rats to control for normal maturational changes. Chemical analysis of fat was done in chow-fed intact and ovariectomized rats at study end. Data were analyzed by t-tests and planned comparisons. RESULTS Body mass, TAT, total fat mass, fat-free body mass, and %IAAT all increased in chow-fed intact rats during the 41 d study. In chow-fed rats, ovariectomy increased excess body mass, TAT, fat mass, fat-free body mass, and SAT, but had little effect on IAAT, in chow-fed rats, leading to a decrease in %IAAT. Ensure feeding markedly increased SAT, IAAT and TAT and did not significantly affect %IAAT. Ovariectomy had similar effects in Ensure-fed rats as in chow-fed rats, although less statistically reliable. Estradiol treatment prevented all the effects of ovariectomy. CONCLUSIONS Both ovariectomy in rats and menopause are associated with increased TAT. After ovariectomy, fat is preferentially deposited as SAT and lean body mass increases, whereas after menopause fat is preferentially deposited as IAAT and lean body mass decreases. These opposite effects of ovariectomy and menopause on regional AT distribution and lean body mass indicate that ovariectomy in rats is not a homologous model of menopause-associated changes in body composition that should be used with great caution in investigations of adiposity-related diseases.
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Affiliation(s)
- Viktoria Gloy
- Physiology and Behaviour Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
| | - Wolfgang Langhans
- Physiology and Behaviour Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
| | - Jacquelien JG Hillebrand
- Physiology and Behaviour Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
- Clinical Chemistry, Ziekenhuisgroep Twente Hengelo, the Netherlands
| | - Nori Geary
- Physiology and Behaviour Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
| | - Lori Asarian
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Switzerland
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Abstract
PURPOSE The purposes of this study were to suppress estradiol levels in adolescent (postpubertal rats) using gonadotropin-releasing hormone antagonist (GnRH-a) injections and to determine the changes in bone structure and mechanical strength. METHODS In an Institutional Animal Care and Use Committee-approved study, female rats at 23 d of age were assigned to a baseline group (BL65; n = 10) sacrificed on day 65, a control group (Control; n = 15) sacrificed on day 90, or an experimental group (AMEN; n = 9) sacrificed on day 90 that received daily injections of GnRH-a for a 25-d period from 65 to 90 d of age (2.5 mg·kg(-1) per dose). RESULTS Body weights were similar on day 65; however, the AMEN group was significantly heavier than the Control group (17%, P = 0.001) on day 90. In the AMEN rats relative to the Control group, plasma estradiol levels were reduced by 36% (P = 0.0001) and plasma insulin-like growth factor 1 levels were 24% higher (P = 0.003). In the femur, there was no change in periosteal bone apposition or total cross-sectional area. The marrow area increased by 13.7% (P = 0.05) resulting in a 7.8% decrease in relative cortical area (P = 0.012), and endocortical bone formation rate increased by 39.4% (P = 0.04). Trabecular volume and number decreased by 51.5% (P = 0.0003) and 49.5% (P = 0.0003), respectively. The absolute peak moments of the tibiae and femurs were unchanged in the AMEN group relative to the Control group, but these were reduced by 8.8% (P = 0.03) and 7.5% (P = 0.09), respectively, when normalized by body weight. CONCLUSIONS Suppression of estradiol by 25 d of GnRH-a administration to 65-d-old (postpubertal) rats reduced trabecular volume and number by about 50%, increased endocortical bone turnover, and reduced relative cortical thickness without changing tibial and femoral total area. These changes in bone structure were associated with no change in absolute mechanical strength possibly because of increases in body weight or in insulin-like growth factor 1 concentrations.
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Affiliation(s)
- McKayla Elle Saine
- Department of Anthropology, College of Liberal Arts, Temple University, Philadelphia, PA, USA
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16
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Bombardier E, Vigna C, Iqbal S, Tiidus PM, Tupling AR. Effects of ovarian sex hormones and downhill running on fiber-type-specific HSP70 expression in rat soleus. J Appl Physiol (1985) 2009; 106:2009-15. [PMID: 19359608 DOI: 10.1152/japplphysiol.91573.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examined the influence of the ovarian sex hormones, estrogen and progesterone, on the fiber-type-specific response of the inducible 70-kDa heat shock protein (HSP70) to damaging exercise in rat soleus. Ovariectomized female rats were divided into three treatment groups (n = 16 per group): sham (S), progesterone (P; 25 mg pellet), and estrogen (E; 0.25 mg pellet). Each treatment group was divided into control and exercised groups. After 8 days of sham or hormone treatment, animals ran downhill intermittently for 90 min (17 m/min, -13.5 degrees grade) on a treadmill, and soleus muscles were removed 24 h postexercise. HSP70 expression was assessed in whole muscle homogenates by Western blotting and in individual muscle fiber types by immunohistochemical analysis of serial cross sections of soleus samples. Comparisons between control groups showed that HSP70 expression in soleus was increased (P < 0.05) in E compared with both S and P. No difference (P > 0.05) was observed between S and P. Following downhill running, HSP70 content in soleus was increased (P < 0.05) compared with control in S and P, but not (P > 0.05) in E. As a result, soleus HSP70 content following downhill running was not different (P > 0.05) between any of the treatment groups. Under all conditions, HSP70 content was higher in type I vs. type II fibers, and the effects of both estrogen and exercise on HSP70 expression in soleus were also more pronounced in type I vs. type II fibers. These results demonstrate that 1) estrogen regulates HSP70 expression in skeletal muscle, increasing basal HSP70 expression and preventing further increases in HSP70 in response to exercise; 2) progesterone is not involved in the regulation of HSP70 expression in skeletal muscle; and 3) the effects of estrogen and exercise on HSP70 expression in skeletal muscle are fiber type specific.
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Affiliation(s)
- E Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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17
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Jiang JMY, Sacco SM, Ward WE. Ovariectomy-Induced Hyperphagia Does Not Modulate Bone Mineral Density or Bone Strength in Rats. J Nutr 2008; 138:2106-10. [DOI: 10.3945/jn.108.093781] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Yingling VR, Taylor G. Delayed pubertal development by hypothalamic suppression causes an increase in periosteal modeling but a reduction in bone strength in growing female rats. Bone 2008; 42:1137-43. [PMID: 18406225 PMCID: PMC2494865 DOI: 10.1016/j.bone.2008.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/28/2008] [Accepted: 02/05/2008] [Indexed: 11/23/2022]
Abstract
The timing of the pubertal growth is a critical event in skeletal development. A delay in the onset of puberty has been correlated with increased stress fracture incidence in young women and as a result, suboptimal skeletal development may affect long-term bone strength. Gonadotropin releasing hormone antagonist (GnRH-a) injections were used to delay the onset of puberty in growing female rats. 23-day-old female rats were injected with a GnRH-antagonist at 2 dosage levels (n=15/group). The Low Dose group (1.25 mg/kg/dose) received daily injections for 27 days (sacrifice 49 days). The High Dose group received (5.0 mg/kg/dose) only 5 days per week over a 26 day period (sacrifice 48 days). Calcein injections measured bone formation activity on the periosteal and endocortical surfaces. Standard histomorphometric and biomechanical analyses were performed on the femora and ash content was measured on the tibiae of all animals. Serum estradiol and insulin-like growth factor (IGF)-1 levels were assayed. Significant delays in pubertal development occurred in the two GnRH-a groups as evidenced by delayed vaginal openings, decreased uterine and ovarian weights and suppressed estradiol levels compared to control. Femoral lengths were significantly shorter in the experimental groups and serum IGF-1 levels were higher than control. Bone strength and stiffness were significantly lower in the GnRH-a groups. Cortical bone area was decreased and total area was not different between groups. There was a significant decrease in % Ct.Ar/T.Ar. The decreased bone strength may have resulted from a decrease in the amount and distribution of bone, however, stress and Young's modulus were also decreased. There was a different response between endocortical formation indices and periosteal formation indices to the GnRH-a protocol. Endocortical bone formation rates decreased and there was an increase in periosteal labeled surface. A dose response between bone strength and GnRH-a dosage was found. The data suggest that hypothalamic suppression during pubertal development resulted in decreased bone strength which may result in fracture development.
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Affiliation(s)
- Vanessa R Yingling
- Department of Kinesiology, College of Health Professions, Temple University, 1800 North Broad Street, Philadelphia, PA 19122, USA.
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19
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Baek K, Barlow AA, Allen MR, Bloomfield SA. Food restriction and simulated microgravity: effects on bone and serum leptin. J Appl Physiol (1985) 2008; 104:1086-93. [DOI: 10.1152/japplphysiol.01209.2007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Leptin is responsible for linking energy metabolism to bone mass. Because astronauts are commonly in negative energy balance during spaceflight, this study was designed to assess individual and combined effects of food restriction and simulated microgravity on bone mass and serum leptin. Six-month-old male Sprague-Dawley rats were randomly assigned to four groups ( n = 12 each): two hindlimb-unloading (HU) groups fed 100% (HU100) and 70% (HU70) and two cage-activity control (CC) groups fed 100% (CC100) and 70% (CC70) of their baseline food requirement. After 28 days, CC100 rats gained body weight, whereas all other groups lost body weight; this loss was greater in HU70 than in CC70 and HU100 rats. Serum leptin decreased in CC70 and HU100 (−60% and −27%, respectively) and was not detectable in HU70 animals. Percent osteoid surface in CC70 and HU100 was lower than that of CC100 (7.80%, 8.60% vs. 10.70%, respectively), and this decrease was more pronounced in HU70 animals (4.38%). Mineral apposition rate of CC70, HU100, and HU70 rats was lower than that of CC100 (1.5, 1.6, and 1.5 vs. 2.1 μm/day, respectively). Bone formation rate of CC70, HU100, and HU70 rats was lower than that of CC100 (13.4, 13.1, and 12.2 vs. 40.8 mm3·mm−2·day−1, respectively). The change in bone formation rate was correlated with the change in serum leptin value over 28 days ( r2 = 0.69, P = 0.0007). We conclude that moderate caloric restriction may cause bone loss at susceptible bone sites to a similar degree as does the unloading effect of microgravity; serum leptin may be an important endocrine regulator contributing to this change in skeletal integrity.
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20
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McClung JM, Davis JM, Wilson MA, Goldsmith EC, Carson JA. Estrogen status and skeletal muscle recovery from disuse atrophy. J Appl Physiol (1985) 2006; 100:2012-23. [PMID: 16497837 DOI: 10.1152/japplphysiol.01583.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although estrogen loss can alter skeletal muscle recovery from disuse, the specific components of muscle regrowth that are estrogen sensitive have not been described. The primary purpose of this study was to determine the components of skeletal muscle mass recovery that are biological targets of estrogen. Intact, ovariectomized (OVX), and ovariectomized with 17β-estradiol replacement (OVX+E2) female rats were subjected to hindlimb suspension for 10 days and then returned to normal cage ambulation for the duration of recovery. Soleus muscle mass returned to control levels by day 7 of recovery in the intact animals, whereas OVX soleus mass did not recover until day 14. Intact rats recovered soleus mean myofiber cross-sectional area (CSA) by day 14 of recovery, whereas the OVX soleus remained decreased (42%) at day 14. OVX mean fiber CSA did return to control levels by day 28 of recovery. The OVX+E2 treatment group recovered mean CSA at day 14, as in the intact animals. Myofibers demonstrating central nuclei were increased at day 14 in the OVX group, but not in intact or OVX+E2 animals. The percent noncontractile tissue was also increased 29% in OVX muscle at day 14, but not in either intact or OVX+E2 groups. In addition, collagen 1a mRNA was increased 45% in OVX muscle at day 14 of recovery. These results suggest that myofiber growth, myofiber regeneration, and extracellular matrix remodeling are estrogen-sensitive components of soleus muscle mass recovery from disuse atrophy.
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MESH Headings
- Animals
- Collagen/analysis
- Collagen/genetics
- Estradiol/blood
- Estradiol/pharmacology
- Estradiol/physiology
- Estradiol/therapeutic use
- Extracellular Matrix/pathology
- Extracellular Matrix/physiology
- Female
- Hindlimb Suspension/physiology
- Muscle Contraction/physiology
- Muscle Fibers, Skeletal/chemistry
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Skeletal/physiology
- Muscle, Skeletal/chemistry
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Disorders, Atrophic/blood
- Muscular Disorders, Atrophic/drug therapy
- Muscular Disorders, Atrophic/pathology
- Muscular Disorders, Atrophic/physiopathology
- Ovariectomy
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Regeneration/drug effects
- Regeneration/physiology
- Time Factors
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Affiliation(s)
- J M McClung
- Integrative Muscle Biology Laboratory, Division of Applied Physiology, University of South Carolina, Department of Exercise Science, 1300 Wheat St., Columbia, SC 29208, USA
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21
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Sitnick M, Foley AM, Brown M, Spangenburg EE. Ovariectomy prevents the recovery of atrophied gastrocnemius skeletal muscle mass. J Appl Physiol (1985) 2006; 100:286-93. [PMID: 16150841 DOI: 10.1152/japplphysiol.00869.2005] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The recovery of atrophied muscle mass in animals is thought to be dependent on a number of factors including hormones, cytokines, and/or growth factor expression. The Akt/mammalian target of rapamycin (mTOR) signaling pathway is believed to be activated by these various factors, resulting in skeletal muscle growth through the initiation of protein synthesis. It was hypothesized that surgical removal of the ovaries (Ovx) may alter activation of the Akt/mTOR signaling pathway, a mechanism necessary for muscle regrowth. To test this, 36 Sprague-Dawley rats underwent Ovx or sham surgeries. A portion of the animals were then subjected to hindlimb unloading (HLU) for 28 days. After HLU, one group of Sham and Ovx rats underwent a 14-day recovery period in which the animals were allowed free cage ambulation. The HLU animals demonstrated ∼21–27% reduction in medial gastrocnemius muscle mass irrespective of whether the ovaries were intact or not. The Sham animals that were reloaded recovered their atrophied muscle mass; however, the Ovx group failed to recover any of the atrophied muscle mass with reloading. The failure to recover muscle mass in the Ovx group was associated with reduced phosphorylation levels of both Akt and p70s6k, whereas in the Sham recovery animals no reductions were found in Akt phosphorylation and significant increases in p70s6k activation were detected. Finally, no differences were detected in mTOR phosphorylation in any of Sham or Ovx groups. These results suggest that ovariectomy surgeries could be detrimental to the recovery of atrophied muscle mass.
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Affiliation(s)
- Mitchell Sitnick
- Molecular, Cellular, and Integrative Physiology Graduate Group, University of California, Davis, One Shields Ave., Davis, California 95616, USA
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22
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Vasconcellos LDS, Sabino KR, Petroianu A. Relação entre ooforectomia e peso em modelo experimental. Rev Col Bras Cir 2005. [DOI: 10.1590/s0100-69912005000300006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJETIVO: Avaliar a influência da privação dos hormônios ovarianos no ganho ponderal, em modelo experimental. MÉTODO: Foram utilizadas 40 ratas fêmeas adultas, distribuídas aleatoriamente em três grupos: Grupo 1 (n=10) - controle, Grupo 2 (n=10) - submetido apenas à laparotomia, Grupo 3 (n=20) - submetido à ooforectomia total bilateral. Os animais foram pesados semanalmente durante 30 semanas e os resultados foram avaliados pelo teste t de Student, com significância para p < 0,05. RESULTADOS: As ratas ooforectomizadas apresentaram ganho ponderal maior do que as demais, sendo a diferença significativa a partir da 9ª semana e persistindo até o fim do experimento. CONCLUSÕES: No presente trabalho, a privação dos hormônios ovarianos foi um fator relacionado com o maior ganho ponderal, em ratas.
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Affiliation(s)
| | | | - Andy Petroianu
- Universidade Federal de Minas Gerais; Universidade de São Paulo; Universidade Federal de São Paulo; Conselho Nacional de Desenvolvimento Científico e Tecnológico
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23
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Cifuentes M, Advis JP, Shapses SA. Estrogen prevents the reduction in fractional calcium absorption due to energy restriction in mature rats. J Nutr 2004; 134:1929-34. [PMID: 15284378 PMCID: PMC4006999 DOI: 10.1093/jn/134.8.1929] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Weight reduction is a risk factor for bone loss. We previously showed that energy restriction is associated with a decrease in calcium (Ca) absorption and decreased estrogenic activity (EA). We hypothesized that this hypoestrogenic status may be the cause of the decrease in Ca absorption and that estrogen replacement during energy restriction would prevent it. Six-month-old rats were ovariectomized and implanted subcutaneously with 17beta-estradiol (E(2)) pellets to maintain levels within the physiological range. After 3 wk, rats ate ad libitum [control (CTL) group, n = 12] or were 40% energy restricted (EnR group, n = 12) for 10 wk. At the end of this study, rats were divided into 2 groups according to their uterine weight: those with higher EA and those with lower EA. Whereas CTL rats gained approximately 46% weight from baseline, EnR rats maintained their weight throughout the study. Energy restriction was associated with lower Ca absorption (5-d measurement, (45)Ca radioisotope) and Ca balance in lower EA but not higher EA rats. Similarly, Ca absorption was correlated with both serum E(2) (r = 0.68, P < 0.05) and body weight (r = 0.72, P < 0.05) in rats with lower EA but not in those with higher EA. Finally, 24-h corticosterone excretion was higher in EnR than in CTL rats, a response that was blunted in the higher EA rats. Our findings suggest that decreases in estrogen and hyperadrenocorticism with energy restriction play an important role in the regulation of Ca absorption and balance.
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Affiliation(s)
| | - Juan P. Advis
- Department of Animal Sciences, Rutgers University, New Brunswick, NJ
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24
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Vasconcellos LS, Leite JM, Sabino KR, Petroianu A. Influência da ooforectomia na variação ponderal em ratas jovens e adultas. ACTA ACUST UNITED AC 2004; 48:299-304. [PMID: 15640886 DOI: 10.1590/s0004-27302004000200014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Para avaliar a influência do tempo de ooforectomia na variação ponderal, foram utilizadas 60 ratas, divididas em dois grupos (30 em cada grupo): Grupo A - jovens; e Grupo B - adultas. Os animais de cada grupo foram subdivididos em três subgrupos: Subgrupo 1 - controle (n= 6); Subgrupo 2 - laparotomia (n= 6); Subgrupo 3 (n= 18) - ooforectomia total bilateral. Os animais foram pesados semanalmente durante 13 semanas e os resultados foram avaliados pelo teste t de Student, com significância para p<0,05. As ratas ooforectomizadas tiveram ganho ponderal maior do que as demais, sendo a diferença significativa a partir da 11ª semana no Grupo A e 9ª semana no Grupo B, persistindo até o fim do experimento. No presente trabalho, a ooforectomia bilateral em ratas relacionou-se com maior ganho ponderal, independente da idade dos animais.
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Affiliation(s)
- Leonardo S Vasconcellos
- Departamento de Cirurgia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG
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25
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Abstract
The rodent grip strength test was developed decades ago and is a putative measure of muscular strength. This test has been included in the functional observational battery (FOB) to screen for neurobehavioral toxicity, and changes in grip strength have been interpreted as evidence of motor neurotoxicity. Despite its widespread use, questions remain about what the grip strength test actually measures. In this study, potential confounders of the grip strength test were identified and tested, including operational parameters, disruption of peripheral sensory function and changes in body weight. Operational parameters (sampling rate, system type and trial angle but not trial speed) had dramatic effects on grip strength data. Doxorubicin (DX, 10 mg/kg iv) was used to cause sensory impairment. It decreased forelimb and hindlimb grip strength (by 27% and 32%, respectively, compared with controls), an effect that was correlated with degeneration of peripheral and central sensory components (distal tibial and sural nerves, dorsal funiculus of the spinal cord and dorsal, but not ventral, spinal roots). Feed restriction-induced loss of body weight (26% compared with controls) and muscle mass (20% compared with controls) reversibly decreased both forelimb and hindlimb grip strength (18% and 17%, respectively, compared with controls). Ignoring these confounding factors could potentially lead to increased data variability and inconsistency within single studies, across studies and in historical control data sets. To assist in data interpretation and evaluation of grip strength results, it is suggested that exact conditions of application of the test be reported in greater detail. Furthermore, given that the grip strength test can be influenced by factors other than true muscular strength, use of the term grip performance is proposed to better reflect the apical nature of this test.
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Affiliation(s)
- Jacques P J Maurissen
- Toxicology & Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Midland, MI 48674, USA.
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26
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Stupka N, Tiidus PM. Effects of ovariectomy and estrogen on ischemia-reperfusion injury in hindlimbs of female rats. J Appl Physiol (1985) 2001; 91:1828-35. [PMID: 11568169 DOI: 10.1152/jappl.2001.91.4.1828] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of estrogen and ovariectomy on indexes of muscle damage after 2 h of complete hindlimb ischemia and 2 h of reperfusion were investigated in female Sprague-Dawley rats. The rats were assigned to one of three experimental groups: ovariectomized with a 17beta-estradiol pellet implant (OE), ovariectomized with a placebo pellet implant (OP), or control with intact ovaries (R). It was hypothesized that following ischemia-reperfusion (I/R), muscle damage indexes [serum creatine kinase (CK) activity, calpain-like activity, inflammatory cell infiltration, and markers of lipid peroxidation (thiobarbituric-reactive substances)] would be lower in the OE and R rats compared with the OP rats due to the protective effects of estrogen. Serum CK activity following I/R was greater (P < 0.01) in the R rats vs. OP rats and similar in the OP and OE rats. Calpain-like activity was greatest in the R rats (P < 0.01) and similar in the OP and OE rats. Neutrophil infiltration was assessed using the myeloperoxidase (MPO) assay and immunohistochemical staining for CD43-positive (CD43+) cells. MPO activity was lower (P < 0.05) in the OE rats compared with any other group and similar in the OP and R rats. The number of CD43+ cells was greater (P < 0.01) in the OP rats compared with the OE and R rats and similar in the OE and R rats. The OE rats had lower (P < 0.05) thiobarbituric-reactive substance content following I/R compared with the R and OP rats. Indexes of muscle damage were consistently attenuated in the OE rats but not in the R rats. A 10-fold difference in serum estrogen content may mediate this. Surprisingly, serum CK activity and muscle calpain-like activity were lower (P < 0.05) in the OP rats compared with the R rats. Increases in serum insulin-like growth factor-1 content (P < 0.05) due to ovariectomy were hypothesized to account for this finding. Thus both ovariectomy and estrogen supplementation have differential effects on indexes of I/R muscle damage.
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Affiliation(s)
- N Stupka
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Ontario, Canada N2L 3C5
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