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Wu CY, Lin YH, Hsieh HH, Chung YH, Hsu ST, Peng SL. The effect of estrogen therapy on cerebral metabolism in diabetic female rats. Comput Struct Biotechnol J 2023; 21:4769-4776. [PMID: 37841332 PMCID: PMC10570627 DOI: 10.1016/j.csbj.2023.09.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 09/20/2023] [Accepted: 09/24/2023] [Indexed: 10/17/2023] Open
Abstract
The impact of estrogen on brain function, especially in individuals with diabetes, remains uncertain. This study aims to compare cerebral glucose metabolism levels in intact rats, ovariectomized (OVX) rats, and 17β-estradiol (E2)-treated OVX diabetic female rats. Sixteen rats were administered a single intraperitoneal injection of 70 mg/kg streptozotocin (STZ) to induce diabetes (intact, n = 6; OVX, n = 6; OVX+E2-treated, n = 4). Additionally, 18 rats received an equivalent solvent dose via intraperitoneal injection (intact, n = 6; OVX, n = 6; OVX+E2-treated, n = 6). After 4 weeks of STZ or solvent administration, positron emission tomography scans with 18F-fluorodeoxyglucose (18F-FDG) injection were employed to assess cerebral glucose metabolism. The diabetic rats exhibited substantial reductions in 18F-FDG uptake across all brain regions (all P < 0.01), in contrast to the control rats. Moreover, intact and OVX + E2-treated diabetic female rats displayed more pronounced decreases in cerebral glucose metabolism in the amygdala and hippocampus compared to OVX diabetic female rats (P < 0.05). These findings suggest that diabetes creates an environment wherein estrogen exacerbates neuropathology and intensifies neuronal activity.
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Affiliation(s)
- Chun-Yi Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei Branch, Taipei, Taiwan
| | - Yu-Hsin Lin
- Department of Pharmacy, National Yang Ming Chiao Tung University, Taipei Branch, Taipei, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Hsin-Hua Hsieh
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei Branch, Taipei, Taiwan
| | - Yi-Hsiu Chung
- Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shih-Ting Hsu
- Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
- Neuroscience and Brain Disease Center, China Medical University, Taiwan
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2
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Tronson NC, Schuh KM. Hormonal contraceptives, stress, and the brain: The critical need for animal models. Front Neuroendocrinol 2022; 67:101035. [PMID: 36075276 DOI: 10.1016/j.yfrne.2022.101035] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/26/2022] [Accepted: 09/01/2022] [Indexed: 01/10/2023]
Abstract
Hormonal contraceptives are among the most important health and economic developments in the 20thCentury, providing unprecedented reproductive control and a range of health benefits including decreased premenstrual symptoms and protections against various cancers. Hormonal contraceptives modulate neural function and stress responsivity. These changes are usually innocuous or even beneficial, including their effects onmood. However, in approximately 4-10% of users, or up to 30 million people at any given time, hormonal contraceptives trigger depression or anxiety symptoms. How hormonal contraceptives contribute to these responses and who is at risk for adverse outcomes remain unknown. In this paper, we discussstudies of hormonal contraceptive use in humans and describe the ways in which laboratory animal models of contraceptive hormone exposure will be an essential tool for expanding findings to understand the precise mechanisms by which hormonal contraceptives influence the brain, stress responses, and depression risk.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
| | - Kristen M Schuh
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
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3
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Effect of 17β-estradiol on the daily pattern of ACE2, ADAM17, TMPRSS2 and estradiol receptor transcription in the lungs and colon of male rats. PLoS One 2022; 17:e0270609. [PMID: 35763527 PMCID: PMC9239479 DOI: 10.1371/journal.pone.0270609] [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: 03/04/2022] [Accepted: 06/13/2022] [Indexed: 11/19/2022] Open
Abstract
Covid-19 progression shows sex-dependent features. It is hypothesized that a better Covid-19 survival rate in females can be attributed to the presence of higher 17β-estradiol (E2) levels in women than in men. Virus SARS-CoV-2 is enabled to enter the cell with the use of angiotensin converting enzyme 2 (ACE2). The expression of several renin-angiotensin system components has been shown to exert a rhythmic pattern, and a role of the circadian system in their regulation has been implicated. Therefore, the aim of the study is to elucidate possible interference between E2 signalling and the circadian system in the regulation of the expression of ACE2 mRNA and functionally related molecules. E2 was administered at a dosage of 40 μg/kg/day for 7 days to male Wistar rats, and sampling of the lungs and colon was performed during a 24-h cycle. The daily pattern of expression of molecules facilitating SARS-CoV-2 entry into the cell, clock genes and E2 receptors was analysed. As a consequence of E2 administration, a rhythm in ACE2 and TMPRSS2 mRNA expression was observed in the lungs but not in the colon. ADAM17 mRNA expression showed a pronounced rhythmic pattern in both tissues that was not influenced by E2 treatment. ESR1 mRNA expression exerted a rhythmic pattern, which was diminished by E2 treatment. The influence of E2 administration on ESR2 and GPER1 mRNA expression was greater in the lungs than in the colon as a significant rhythm in ESR2 and GPER1 mRNA expression appeared only in the lungs after E2 treatment. E2 administration also increased the amplitude of bmal1 expression in the lungs, which implicates altered functioning of peripheral oscillators in response to E2 treatment. The daily pattern of components of the SARS-CoV-2 entrance pathway and their responsiveness to E2 should be considered in the timing of pharmacological therapy for Covid-19.
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Nowak B, Matuszewska A, Szeląg A, Danielewski M, Dziewiszek W, Nikodem A, Filipiak J, Jędrzejuk D, Bolanowski M, Kucharska AZ, Piórecki N, Piasecki T, Sozański T. Cornelian cherry (Cornus mas L.) extract reduces cardiovascular risk and prevents bone loss in ovariectomized Wistar rats. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.104974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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5
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Nowak B, Matuszewska A, Popłoński J, Nikodem A, Filipiak J, Tomanik M, Dziewiszek W, Danielewski M, Belowska-Bień K, Kłobucki M, Sordon S, Jędrzejuk D, Ceremuga I, Trocha M, Sozański T, Piasecki T, Bolanowski M, Huszcza E, Szeląg A. Prenylflavonoids counteract ovariectomy-induced disturbances in rats. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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6
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de Almeida ERM, Martinelli ECL, Pereira EC, Raspantini LER, Hueza IM. Alternative method for oral administration of insoluble toxins to rats. A prenatal study of L-mimosine. Toxicon 2021; 202:82-89. [PMID: 34582830 DOI: 10.1016/j.toxicon.2021.09.013] [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: 08/10/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
L-mimosine is a compound found in Leucaena leucocephala, that is used as animal feed due to its high protein content, but it can also cause intoxication. Due to its low solubility in organic and aqueous solvents, its administration in laboratory animals is difficult, especially in delicate periods such as pregnancy. Thus, to circumvent such problems, this study proposes a stress-free form of oral administration with gelatin tablets with flavoring (meat broth) for 14 consecutive days of the gestational period (GD06 to GD20). For that, 17 pregnant Wistar rats divided into 3 groups were used: control (CO; n = 5) not treated; gelatin (GEL; n = 6), which received a gelatin tablet with flavoring; and gelatin with flavoring added 140 mg/kg of L-mimosine (GM; n = 6). All animals received feed and water ad libitum. The parameters analyzed were body weight gain, water and feed consumption, serum biochemistry, blood count and reproductive indices. Among these, only the real and total weight gains of dams showed statistically significant differences, with a decrease in the group GM. Thus, we could observe that flavored gelatin was an efficient and effective administration method to insoluble compounds and long-term administration to pregnant rats, with quick adaptation and without refusal by the animals. In addition, we could observe a direct effect of L-mimosine on the animals' weight gain; however, the dose administered was not sufficient to confer maternal and fetal toxicity.
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Affiliation(s)
- Elaine R M de Almeida
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, S.P., Brazil
| | - Elaine C L Martinelli
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, S.P., Brazil
| | - Edimar C Pereira
- Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo (ICAQF-UNIFESP), Diadema, S.P., Brazil
| | - Leonila E R Raspantini
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, S.P., Brazil
| | - Isis M Hueza
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, S.P., Brazil; Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo (ICAQF-UNIFESP), Diadema, S.P., Brazil.
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7
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Rabiant K, Antol J, Naassila M, Pierrefiche O. Sex difference in the vulnerability to hippocampus plasticity impairment after binge-like ethanol exposure in adolescent rat: Is estrogen the key? Addict Biol 2021; 26:e13002. [PMID: 33511744 DOI: 10.1111/adb.13002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 02/01/2023]
Abstract
Binge drinking during adolescence induces memory impairments, and evidences suggest that females are more vulnerable than males. However, the reason for such a difference is unclear, whereas preclinical studies addressing this question are lacking. Here we tested the hypothesis that endogenous estrogen level (E2) may explain sex differences in the effects of ethanol on hippocampus plasticity, the cellular mechanism of memory. Long-term depression (LTD) in hippocampus slice of pubertal female rats was recorded 24 h after two ethanol binges (3 g/kg, i.p., 9 h apart). Neither the estrous cycle nor ethanol altered LTD. However, if ethanol was administered during proestrus (i.e., at endogenous E2 peak), LTD was abolished 24 h later, whereas NMDA-fEPSPs response to a GluN2B antagonist increased. The abolition of LTD was not observed in adult female rats. Exogenous E2 combined with ethanol replicated LTD abolition in pubertal, prepubertal female, and in pubertal male rats without changes in ethanol metabolism. In male rats, a higher dose of ethanol was required to abolish LTD at 24-h delay. In pubertal female rats, tamoxifen, an antagonist of estrogen receptors, blocked the impairing effects of endogenous and exogenous E2 on LTD, suggesting estrogen interacts with ethanol through changes in gene expression. In addition, tamoxifen prevented LTD abolition at 24 h but not at 48-h delay. In conclusion, estrogen may explain the increased vulnerability to ethanol-induced plasticity impairment seen in females compared with males. This increased vulnerability of female rats is likely due to changes in the GluN2B subunit that represent a common target between ethanol and estrogen.
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Affiliation(s)
- Kevin Rabiant
- INSERM, UMR 1247 GRAP, Groupe de Recherche sur l'Alcool et les Pharmacodépendances Univ Picardie Jules Verne, Centre Universitaire de Recherche en Santé (CURS) Amiens France
| | - Johan Antol
- INSERM, UMR 1247 GRAP, Groupe de Recherche sur l'Alcool et les Pharmacodépendances Univ Picardie Jules Verne, Centre Universitaire de Recherche en Santé (CURS) Amiens France
| | - Mickael Naassila
- INSERM, UMR 1247 GRAP, Groupe de Recherche sur l'Alcool et les Pharmacodépendances Univ Picardie Jules Verne, Centre Universitaire de Recherche en Santé (CURS) Amiens France
| | - Olivier Pierrefiche
- INSERM, UMR 1247 GRAP, Groupe de Recherche sur l'Alcool et les Pharmacodépendances Univ Picardie Jules Verne, Centre Universitaire de Recherche en Santé (CURS) Amiens France
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8
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Majewski AR, Chuong LM, Neill HM, Roberts AL, Jerry DJ, Dunphy KA. Sterilization of Silastic Capsules Containing 17β-Estradiol for Effective Hormone Delivery in Mus musculus. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2018; 57. [PMID: 30314533 PMCID: PMC6241387 DOI: 10.30802/aalas-jaalas-18-000030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/16/2018] [Accepted: 06/01/2018] [Indexed: 11/05/2022]
Abstract
Silastic capsules are frequently used to study the physiologic effects of estrogen exposure in animal models. The Officeof Laboratory Animal Welfare requires the sterilization of nonpharmaceutical-grade compounds before use. We compared 2commonly used terminal sterilization methods-ionizing radiation (IR) and ethylene oxide (EO)-for their utility in sterilizingsilastic capsules containing 0.05 or 0.1 mg 17β-estradiol (E2). E2-specific ELISA demonstrated that serum estrogen levelsdid not differ between mice implanted with 0.05-mg E2 capsules that were sterilized with IR or EO and those implanted withnonsterilized capsules. Likewise, mammary gland morphology and progesterone receptor expression and proliferation inmammary epithelium were similar among mice treated with E2 capsules, regardless of sterilization method, and pregnant day15 mice. In addition, IR-sterilized 0.1-mg E2 pellets provided high serum E2. We conclude that neither ionizing radiation norethylene oxide degraded E2 or the cellulose matrix, suggesting that these methods of sterilization are appropriate to provideeffective sterile hormone capsules for animal research.
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Affiliation(s)
- Aliza R Majewski
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
| | - Lynn M Chuong
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
| | - Hannah M Neill
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
| | - Amy L Roberts
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
| | - D Joseph Jerry
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
| | - Karen A Dunphy
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
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9
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Gérard C, Gallez A, Dubois C, Drion P, Delahaut P, Quertemont E, Noël A, Pequeux C. Accurate Control of 17β-Estradiol Long-Term Release Increases Reliability and Reproducibility of Preclinical Animal Studies. J Mammary Gland Biol Neoplasia 2017; 22:1-11. [PMID: 27889857 PMCID: PMC5310554 DOI: 10.1007/s10911-016-9368-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 11/21/2016] [Indexed: 01/06/2023] Open
Abstract
Estrogens are the subject of intensive researches aiming to elucidate their mechanism of action on the various tissues they target and especially on mammary gland and breast cancer. The use of ready-to-use slow releasing devices to administer steroids, especially estrogens, to small experimental animals remains the method of choice in terms of animal well-being and of safety for both the researcher and the animal. In this study, we evaluated and compared, in vitro and in vivo, the release kinetic of estradiol (E2) over sixty days from two different slow-releasing systems: the matrix pellet (MP) and the reservoir implant (RI). We compared the impact of these systems in three E2-sensitive mouse models : mammary gland development, human MCF7 adenocarcinoma xenograft and mouse melanoma progression. The real amount of E2 that is released from both types of devices could differ from manufacturer specifications due to inadequate release for MP and initial burst effect for RI. Compared to MP, the interindividual variability was reduced with RI thanks to a superior control of the E2 release. Depending on the dose-dependent sensitivity of the physiological or pathological readout studied, this could lead to an improvement of the statistical power of in vivo experiments and thus to a reduction of the required animal number. Altogether, our data draw attention on the importance to adequately select the slow-releasing device that is the most appropriated to a specific experiment to better fulfill the 3Rs rule (Replacement, Reduction, Refinement) related to animal welfare and protection.
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Affiliation(s)
- Céline Gérard
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liege, CHU-B23, Hippocrate avenue 13, B-4000, Liège, Belgium
| | - Anne Gallez
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liege, CHU-B23, Hippocrate avenue 13, B-4000, Liège, Belgium
| | - Charline Dubois
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liege, CHU-B23, Hippocrate avenue 13, B-4000, Liège, Belgium
| | - Pierre Drion
- Experimental Surgery unit, GIGA & Credec, University of Liege, 4000, Liège, Belgium
| | | | - Etienne Quertemont
- Department of Psychology, Cognition and Behavior, University of Liege, 4000, Liège, Belgium
| | - Agnès Noël
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liege, CHU-B23, Hippocrate avenue 13, B-4000, Liège, Belgium
| | - Christel Pequeux
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liege, CHU-B23, Hippocrate avenue 13, B-4000, Liège, Belgium.
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10
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Stires H, Saboya M, Globerman SP, Cohick WS. Peroral Estradiol Is Sufficient to Induce Carcinogen-Induced Mammary Tumorigenesis in Ovariectomized Rats without Progesterone. PLoS One 2016; 11:e0162662. [PMID: 27611094 PMCID: PMC5017759 DOI: 10.1371/journal.pone.0162662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 08/28/2016] [Indexed: 12/02/2022] Open
Abstract
A role for estrogens in breast cancer is widely accepted, however, recent evidence highlights that timing and exposure levels are important in determining whether they elicit harmful versus beneficial effects. The rat chemical carcinogen model has been widely used to study the effects of estrogens but conclusions on the levels that lead to tumor development and an absolute requirement for progesterone (P4) are lacking. A newer method of hormone administration mixes hormones with nut butter for peroral consumption allowing for a less stressful method of long-term administration with lower spikes in serum estradiol (E2) levels. The present study was designed to determine if estrogens alone at a physiological dose can drive carcinogen-induced tumors in ovariectomized (OVX) rats or if P4 is also required using this method of hormone administration. Short-term studies were conducted to determine the dose of estrogen (E) that would lead to increased uterine weight following OVX. Subsequently, rats were OVX on postnatal day (PND) 40 then treated daily with E (600 μg/kg/day), P4 (15 mg/kg/day), or the combination. On PND 50, all rats were injected with nitrosomethylurea to induce mammary tumors. Uterine weights, body weights, and serum E2 levels were measured to demonstrate the efficacy of the method for increasing E2 levels during long-term treatment. After 26 weeks, tumor incidence was similar in Sham, E, and E + P4 animals indicating that E was sufficient to induce tumorigenesis when hormone levels were normalized by this method. This study demonstrates peroral administration can be used in long-term studies to elucidate relationships between different types and levels of steroid hormones.
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Affiliation(s)
- Hillary Stires
- Department of Animal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States of America
| | - Mariana Saboya
- Department of Animal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States of America
| | - Samantha P. Globerman
- Department of Animal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States of America
| | - Wendie S. Cohick
- Department of Animal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States of America
- * E-mail:
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11
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Yi H, Bao X, Tang X, Fan X, Xu H. Estrogen modulation of calretinin and BDNF expression in midbrain dopaminergic neurons of ovariectomised mice. J Chem Neuroanat 2016; 77:60-67. [PMID: 27211874 DOI: 10.1016/j.jchemneu.2016.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 05/09/2016] [Accepted: 05/18/2016] [Indexed: 11/19/2022]
Abstract
Estrogen attenuates the loss of dopamine neurons from the substantia nigra in animal models of Parkinson's disease (PD) and excitatory amino-acid induced neurotoxicity by interactions with brain-derived neurotrophic factor (BDNF), and calretinin (CR) containing dopaminergic (DA) neurons. To examine this interaction more closely, we treated the ovariectomised (OVX) mice with estrodial for 10days, and compared these mice to those OVX mice injected with the vehicle or control mice. Estrogen treatment in OVX mice had significantly more tyrosine hydroxylase (TH) positive neurons in the substantia nigra pars compacta (SNpc). Dopamine transporter (DAT) mRNA and BDNF mRNA levels in the midbrain were also significantly increased by estrogen treatment (P<0.05). OVX markedly decreased the number of TH/CR double stained cells in the SNpc (P<0.05), a trend which could be reversed by estrogen treatment. However, the number of GFAP positive cells in the substantia nigra did not show significant changes (P >0.05) after vehicle or estrodial treatment. Furthermore, we found that estrogen treatment abrogated the OVX-induced decrease in the phosphorylated AKT (p-AKT), but not p-ERK. We hypothesize that short-term treatment with estrogen confers neuroprotection to DA neurons by increasing CR in the DA neurons and BDNF in the midbrain, which possibly related to activation of the PI3K/Akt signaling pathway.
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Affiliation(s)
- Hongliang Yi
- Department of Physiology, Third Military Medical University, Chongqing, 400038, PR China; Chongqing City Family Planning Institute, Chongqing, 400020, PR China
| | - Xiaohang Bao
- Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing 400038, PR China
| | - Xiaotong Tang
- Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, PR China
| | - Xiaotang Fan
- Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, PR China.
| | - Haiwei Xu
- Southwest Hospital/Southwest Eye Hospital,Third Military Medical University, Chongqing, 400038, PR China.
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12
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Ingberg E, Theodorsson E, Theodorsson A, Ström JO. Effects of high and low 17β-estradiol doses on focal cerebral ischemia in rats. Sci Rep 2016; 6:20228. [PMID: 26839007 PMCID: PMC4738304 DOI: 10.1038/srep20228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/23/2015] [Indexed: 12/19/2022] Open
Abstract
The majority of the numerous animal studies of the effects of estrogens on cerebral ischemia have reported neuroprotective results, but a few have shown increased damage. Differences in hormone administration methods, resulting in highly different 17β-estradiol levels, may explain the discrepancies in previously reported effects. The objective of the present study was to test the hypothesis that it is the delivered dose per se, and not the route and method of administration, that determines the effect, and that high doses are damaging while lower doses are protective. One hundred and twenty ovariectomized female Wistar rats (n = 40 per group) were randomized into three groups, subcutaneously administered different doses of 17β-estradiol and subjected to transient middle cerebral artery occlusion. The modified sticky tape test was performed after 24 h and the rats were subsequently sacrificed for infarct size measurements. In contrast to our hypothesis, a significant negative correlation between 17β-estradiol dose and infarct size was found (p = 0.018). Thus, no support was found for the hypothesis that 17β-estradiol can be both neuroprotective and neurotoxic merely depending on dose. In fact, on the contrary, the findings indicate that the higher the dose of 17β-estradiol, the smaller the infarct.
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Affiliation(s)
- Edvin Ingberg
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Annette Theodorsson
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Division of Neuroscience, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Department of Neurosurgery, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Jakob O Ström
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Vårdvetenskapligt Forskningscentrum/Centre for Health Sciences, Örebro University Hospital, Region Örebro Län, Örebro, Sweden.,School of Health and Medical Sciences, Örebro University, Örebro, Sweden
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13
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MacDonald TL, Ritchie KL, Davies S, Hamilton MJ, Cervone DT, Dyck DJ. Exercise training is an effective alternative to estrogen supplementation for improving glucose homeostasis in ovariectomized rats. Physiol Rep 2015; 3:3/11/e12617. [PMID: 26603453 PMCID: PMC4673645 DOI: 10.14814/phy2.12617] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 10/13/2015] [Indexed: 01/04/2023] Open
Abstract
The irreversible loss of estrogen (specifically 17-β-estradiol; E2) compromises whole-body glucose tolerance in women. Hormone replacement therapy (HRT) is frequently prescribed to treat estrogen deficiency, but has several deleterious side effects. Exercise has been proposed as an HRT substitute, however, their relative abilities to treat glucose intolerance are unknown. Thirty ovariectomized (OVX) and 20 SHAM (control) rats underwent glucose tolerance tests (GTT) 10 weeks post surgery. Area under the curve (AUC) for OVX rats was 60% greater than SHAM controls (P = 0.0005). Rats were then randomly assigned to the following treatment groups: SHAM sedentary (sed) or exercise (ex; 60 min, 5×/weeks), OVX sed, ex, or E2 (28 μg/kg bw/day) for 4 weeks. OVX ex rats experienced a ∼45% improvement in AUC relative to OVX sed rats, whereas OVX E2 underwent a partial reduction (17%; P = 0.08). Maximal insulin-stimulated glucose uptake in soleus and EDL was not impaired in OVX rats, or augmented with exercise or E2. Akt phosphorylation did not differ in soleus, EDL, or liver of any group. However, OVX ex and OVX E2 experienced greater increases in p-Akt Ser473 in VAT and SQ tissues compared with SHAM and OVX sed groups. Mitochondrial markers CS, COXIV, and core1 were increased in soleus posttraining in OVX ex rats. The content of COXIV was reduced by 52% and 61% in SQ of OVX sed and E2 rats, compared to SHAM controls, but fully restored in OVX ex rats. In summary, exercise restores glucose tolerance in OVX rats more effectively than E2. This is not reflected by alterations in muscle maximal insulin response, but increased insulin signaling in adipose depots may underlie whole-body improvements.
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Affiliation(s)
- Tara L MacDonald
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Kerry L Ritchie
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Sarah Davies
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Melissa J Hamilton
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Daniel T Cervone
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David J Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Liu J, Lin H, Huang Y, Liu Y, Wang B, Su F. Cognitive effects of long-term dydrogesterone treatment used alone or with estrogen on rat menopausal models of different ages. Neuroscience 2015; 290:103-14. [DOI: 10.1016/j.neuroscience.2015.01.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 11/16/2022]
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15
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Mosquera L, Shepherd L, Torrado AI, Torres-Diaz YM, Miranda JD, Segarra AC. Comparison of Two Methods of Estradiol Replacement: their Physiological and Behavioral Outcomes. ACTA ACUST UNITED AC 2015; 6:276. [PMID: 26962471 DOI: 10.4172/2157-7579.1000276] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Fluctuating sex steroids during the estrous or menstrual cycle of mammalian females make it difficult to determine their role on behaviors and physiology. To avoid this, many investigators ovariectomize their animals and administer progesterone, estradiol or a combination of both. Several different strategies are used to administer estradiol, which confounds interpretation of results. This study compared two methods of estradiol replacement implants: Silastic tubes filled with crystalline estradiol benzoate (E2) and commercially available estradiol benzoate pellets. Implants were placed subcutaneously in adult ovariectomized (OVX) rats and blood samples obtained weekly. Control OVX rats received empty Silastic tubes or placebo pellets. Our data shows that E2 plasma levels from rats with Silastic implants peaked after one week and decreased slowly thereafter. In contrast, plasma E2 from commercial pellets peaked after two weeks, increasing and decreasing over time. To validate hormone release, body weight was monitored. All E2 treated animals maintained a similar body weight over the four weeks period whereas an increase in body weight over time was observed in the OVX group that received empty implants, confirming E2 release and supporting the role of E2 in the regulation of body weight. Furthermore, the effects of E2 on basal locomotor activity were assessed using animal activity cages. Results showed no difference between E2 and control group in several locomotor activities. These results indicate that Silastic implants achieve more stable plasma estradiol levels than pellets and thus are a better alternative for studies of estradiol on brain function and behavior.
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Affiliation(s)
- Laurivette Mosquera
- University of Puerto Rico School of Medicine, Department of Physiology, PO Box 365067, San Juan, Puerto Rico 00936-5067, USA
| | - Luz Shepherd
- University of Puerto Rico School of Medicine, Department of Physiology, PO Box 365067, San Juan, Puerto Rico 00936-5067, USA
| | - Aranza I Torrado
- University of Puerto Rico School of Medicine, Department of Physiology, PO Box 365067, San Juan, Puerto Rico 00936-5067, USA
| | - Yvonne M Torres-Diaz
- University of Puerto Rico School of Medicine, Department of Physiology, PO Box 365067, San Juan, Puerto Rico 00936-5067, USA
| | - Jorge D Miranda
- University of Puerto Rico School of Medicine, Department of Physiology, PO Box 365067, San Juan, Puerto Rico 00936-5067, USA
| | - Annabell C Segarra
- University of Puerto Rico School of Medicine, Department of Physiology, PO Box 365067, San Juan, Puerto Rico 00936-5067, USA
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16
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Molina-Cimadevila MJ, Segura S, Merino C, Ruiz-Reig N, Andrés B, de Madaria E. Oral self-administration of buprenorphine in the diet for analgesia in mice. Lab Anim 2014; 48:216-224. [DOI: 10.1177/0023677214532454] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Postsurgical oral self-administration of analgesics in rodents is an interesting technique of providing analgesia, avoiding the negative effects of manipulation. Several strategies, using gelatin or nutella, have already been described. However, rodents require some habituation period to reach a good intake because of their neophobic behavior. The current study aimed to explore whether buprenorphine when mixed with an extruded diet offers a potential treatment option in the pain management of mice using a triple approach: by measuring the spontaneous intake in healthy animals; by using the hot-plate test; and finally by assessing the drug’s ability to provide postoperative analgesia in a surgical intervention of moderate severity (intra-utero electroporation). Mice consumed during 20 hours, similar amounts of extruded diet alone, mixed with glucosaline, and mixed with buprenorphine (0.03 mg per pellet) or meloxicam (0.25 mg per pellet) both of which were diluted in glucosaline, showing that no neophobia was associated with these administrations. Relative increase from baseline latency (% maximal possible effect) in the hot-plate test at 20 h of administration was significantly higher for oral buprenorphine in diet 0.03 mg/pellet, and diet 0.15 mg/pellet, compared with placebo and no differences were found between those oral administrations and subcutaneous buprenorphine 0.1 mg/kg measured 3 h later. The treatment was also effective in attenuating the reductions in food consumption and body weight that occur after surgery. These data suggest that providing buprenorphine with the diet is a feasible and effective way of self-administration of analgesia in mice and does not cause neophobia and may easily contribute to the refinement of surgical procedures.
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Affiliation(s)
- M J Molina-Cimadevila
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, Alicante, Sapin
| | - S Segura
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, Alicante, Sapin
| | - C Merino
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, Alicante, Sapin
| | - N Ruiz-Reig
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, Alicante, Sapin
| | - B Andrés
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, Alicante, Sapin
| | - E de Madaria
- Sección de Aparato Digestivo, Hospital General Universitario de Alicante, Alicante, Spain
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17
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Ström JO, Ingberg E. Impact of methodology on estrogens' effects on cerebral ischemia in rats: an updated meta-analysis. BMC Neurosci 2014; 15:22. [PMID: 24495535 PMCID: PMC3975994 DOI: 10.1186/1471-2202-15-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/29/2014] [Indexed: 12/15/2022] Open
Abstract
Background Although most animal stroke studies have demonstrated potent neuroprotective effects of estrogens, there are a number of articles reporting the opposite. In 2009, we made the case that this dichotomy was related to administered estrogen dose. Several other suggestions for the discordant results have also been propagated, including the age of the experimental animals and the length of hypoestrogenicity prior to estrogen administration. These two suggestions have gained much popularity, probably because of their kinship with the window of opportunity hypothesis, which is commonly used to explain the analogous dichotomy among human studies. We were therefore encouraged to perform an updated meta-analysis, and to improve it by including all relevant variables in a large multiple regression model, where the impact of confounders could be controlled for. Results The multiple regression model revealed an indisputable impact of estrogen administration mode on the effects of estrogens in ischemic stroke. Subcutaneous slow-release pellets differed from the injection and silastic capsule treatments in terms of impact of estrogens on ischemic stroke, showing that the first mentioned were more prone to render estrogens damaging. Neither the use of elderly animals nor the adoption of longer wash-out periods influenced estrogens’ effects on experimental ischemic stroke in rats. Conclusions We conclude that the discordant results regarding estrogens’ effects in rat models of ischemic stroke are a consequence of differences in estrogen administration modes. These results are not only of importance for the ongoing debate regarding menopausal hormone therapy, but also have an important bearing on experimental stroke methodology and the apparent translational roadblock for suggested stroke interventions.
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Affiliation(s)
- Jakob O Ström
- Vårdvetenskapligt Forskningscentrum/Centre for Health Sciences, Örebro University Hospital, County Council of Örebro, Örebro SE-703 62, Sweden.
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18
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Strom JO, Ingberg E, Theodorsson E, Theodorsson A. Effects of high and low 17β-estradiol doses on focal cerebral ischemia: negative results. Sci Rep 2013; 3:3111. [PMID: 24177749 PMCID: PMC6505964 DOI: 10.1038/srep03111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/11/2013] [Indexed: 01/11/2023] Open
Abstract
The reasons why some animal studies indicate that estrogens increase focal cerebral ischemic damage while others show estrogen-induced neuroprotection has hitherto not been fully elucidated. Recent evidence indicates that discrepancies in hormone administration paradigms, resulting in highly different serum hormone concentrations, may account for the dichotomy. The current study aimed to test this hypothesis. Sixty ovariectomized female rats were randomized into three groups differing in 17β-estradiol regimens, and transient focal cerebral ischemia was subsequently induced. All animals were subjected to a small functional testing battery, and three days after MCAo they were sacrificed for infarct size assessment. Infarct sizes did not differ between groups, however clear discrepancies were seen in body weight and feeding behavior. In comparison to sham-operated animals, ovariectomized rats rapidly increased in body weight, whereas the opposite was seen in rats receiving 17beta-estradiol. The weight gain in the ovariectomized rats was paralleled by an increased food intake.
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Affiliation(s)
- Jakob O Strom
- Clinical Chemistry, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Department of Clinical Chemistry, County Council of Östergötland, Linköping, Sweden
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19
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Wibowo E, Wassersug RJ. The effect of estrogen on the sexual interest of castrated males: Implications to prostate cancer patients on androgen-deprivation therapy. Crit Rev Oncol Hematol 2013; 87:224-38. [DOI: 10.1016/j.critrevonc.2013.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 12/09/2012] [Accepted: 01/16/2013] [Indexed: 11/30/2022] Open
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20
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Marks KA, Kitson AP, Shaw B, Mutch DM, Stark KD. Stearoyl-CoA desaturase 1, elongase 6 and their fatty acid products and precursors are altered in ovariectomized rats with 17β-estradiol and progesterone treatment. Prostaglandins Leukot Essent Fatty Acids 2013; 89:89-96. [PMID: 23777599 DOI: 10.1016/j.plefa.2013.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/09/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
Abstract
Sex differences in monounsaturated fatty acid (MUFA) levels suggest ovarian hormones may affect MUFA biosynthesis. Sprague-Dawley rats (8 weeks of age) were ovariectomized or sham operated with ovariectomized rats implanted with a constant-release hormone pellet providing 17β-estradiol, progesterone, both or neither at 10 weeks of age. After 14 days, rats were fasted overnight and sacrificed to collect plasma and livers for analysis. Hepatic stearoyl-CoA desaturase (SCD1) expression was unchanged between ovariectomized and sham controls, as determined by microarray and immunoblotting. However, SCD1 protein was increased in rats treated with estradiol plus progesterone. Elongase 6 protein levels were increased with 17β-estradiol treatment compared with sham. Rats treated with 17β-estradiol and 17β-estradiol plus progesterone had increased 16:0, 18:0, 16:1n-7 and 18:1n-7 in hepatic and plasma phospholipids. Ovarian hormones appear to be involved with MUFA biosynthesis, but the relationship appears complex and involves elongase 6 and SCD1.
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Affiliation(s)
- Kristin A Marks
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada, N2L 3G1
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21
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Strom JO, Nilsson T, Theodorsson E. Effects of 17β-estradiol on galanin(1-29)- and galanin(1-16)-like immunoreactivities. Peptides 2013; 43:1-7. [PMID: 23402789 DOI: 10.1016/j.peptides.2013.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/23/2013] [Accepted: 01/23/2013] [Indexed: 11/21/2022]
Abstract
There are reasons to believe that the galanin neuropeptide family could include more than the two hitherto known members (galanin(1-29) and galanin-like peptide), such as the existence of at least three galanin receptors and the fact that synthetic short-chain homologues have effects and binding sites that are distinct from those of galanin(1-29). The current study uses a radioimmunoassay based on a polyclonal rabbit antiserum raised against galanin(1-16) to study the concentrations of galanin(1-16) like immunoreactivity (LI) in the various parts of the brain and gut of ovariectomized female rats, and investigates the effects of different concentrations of estradiol on these concentrations in relation to galanin(1-29)-LI. Galanin(1-29) concentrations were increased by 17β-estradiol administration in almost all examined tissues whereas galanin(1-16)-LI was increased by 17β-estradiol treatment in most of the gut, but only in the pituitary of the brain. Furthermore, the relation between galanin(1-29)-LI and galanin(1-16)-LI varied substantially from tissue to tissue. The main hypothesis, that galanin(1-16)-LI would be affected by 17β-estradiol in brain and/or gut, was confirmed in addition to the secondary hypothesis, stating that the pattern of galanin(1-16)-LI changes would differ from that of galanin(1-29). The study indicates that galanin(1-16)-LI is estrogen-responsive but that its concentrations are regulated differently from that of galanin(1-29). This is strongly indicative of a biological relevance of this potentially new member of the galanin neuropeptide family.
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Affiliation(s)
- Jakob O Strom
- Clinical Chemistry, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
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22
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Abelson KSP, Jacobsen KR, Sundbom R, Kalliokoski O, Hau J. Voluntary ingestion of nut paste for administration of buprenorphine in rats and mice. Lab Anim 2012; 46:349-51. [DOI: 10.1258/la.2012.012028] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An adequate analgesic strategy is important to improve the postoperative recovery and welfare of laboratory rats and mice. It is desirable that the method for administering the drug is non-invasive and stress-free. We have previously validated a method for administering buprenorphine in a nut paste for voluntary ingestion. This method has many advantages over parenteral administration. To use the method in a successful way, however, it is important to prepare and administer the mix correctly. The present paper describes in detail how to implement the method, by means of habituation, presentation, adequate concentrations and amounts of buprenorphine/nut paste, and dosage of buprenorphine to rats and mice.
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Affiliation(s)
- Klas S P Abelson
- Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Kirsten R Jacobsen
- Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Renée Sundbom
- Department of Neuroscience, Division of Comparative Medicine, Uppsala University, Uppsala, Sweden
| | - Otto Kalliokoski
- Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jann Hau
- Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
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23
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Ström JO, Theodorsson A, Ingberg E, Isaksson IM, Theodorsson E. Ovariectomy and 17β-estradiol replacement in rats and mice: a visual demonstration. J Vis Exp 2012:e4013. [PMID: 22710371 DOI: 10.3791/4013] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Estrogens are a family of female sexual hormones with an exceptionally wide spectrum of effects. When rats and mice are used in estrogen research they are commonly ovariectomized in order to ablate the rapidly cycling hormone production, replacing the 17β-estradiol exogenously. There is, however, lack of consensus regarding how the hormone should be administered to obtain physiological serum concentrations. This is crucial since the 17β-estradiol level/administration method profoundly influences the experimental results. We have in a series of studies characterized the different modes of 17β-estradiol administration, finding that subcutaneous silastic capsules and per-oral nut-cream Nutella are superior to commercially available slow-release pellets (produced by the company Innovative Research of America) and daily injections in terms of producing physiological serum concentrations of 17β-estradiol. Amongst the advantages of the nut-cream method, that previously has been used for buprenorphine administration, is that when used for estrogen administration it resembles peroral hormone replacement therapy and is non-invasive. The subcutaneous silastic capsules are convenient and produce the most stable serum concentrations. This video article contains step-by-step demonstrations of ovariectomy and 17β-estradiol hormone replacement by silastic capsules and peroral Nutella in rats and mice, followed by a discussion of important aspects of the administration procedures.
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Affiliation(s)
- Jakob O Ström
- Clinical Chemistry and Neurosurgery, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University.
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24
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Ingberg E, Theodorsson A, Theodorsson E, Strom JO. Methods for long-term 17β-estradiol administration to mice. Gen Comp Endocrinol 2012; 175:188-93. [PMID: 22137913 DOI: 10.1016/j.ygcen.2011.11.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 10/28/2011] [Accepted: 11/11/2011] [Indexed: 10/15/2022]
Abstract
Rodent models constitute a cornerstone in the elucidation of the effects and biological mechanisms of 17β-estradiol. However, a thorough assessment of the methods for long-term administration of 17β-estradiol to mice is lacking. The fact that 17β-estradiol has been demonstrated to exert different effects depending on dose emphasizes the need for validated administration regimens. Therefore, 169 female C57BL/6 mice were ovariectomized and administered 17β-estradiol using one of the two commonly used subcutaneous methods; slow-release pellets (0.18 mg, 60-day release pellets; 0.72 mg, 90-day release pellets) and silastic capsules (with/without convalescence period, silastic laboratory tubing, inner/outer diameter: 1.575/3.175 mm, filled with a 14 mm column of 36 μg 17β-estradiol/mL sesame oil), or a novel peroral method (56 μg 17β-estradiol/day/kg body weight in the hazelnut cream Nutella). Forty animals were used as ovariectomized and intact controls. Serum samples were obtained weekly for five weeks and 17β-estradiol concentrations were measured using radioimmunoassay. The peroral method resulted in steady concentrations within--except on one occasion--the physiological range and the silastic capsules produced predominantly physiological concentrations, although exceeding the range by maximum a factor three during the first three weeks. The 0.18 mg pellet yielded initial concentrations an order of magnitude higher than the physiological range, which then decreased drastically, and the 0.72 mg pellet produced between 18 and 40 times higher concentrations than the physiological range during the entire experiment. The peroral method and silastic capsules described in this article constitute reliable modes of administration of 17β-estradiol, superior to the widely used commercial pellets.
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Affiliation(s)
- E Ingberg
- Department of Clinical and Experimental Medicine/Clinical Chemistry, Linkoping University, Linkoping SE-581 85, Sweden.
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