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Sadie-Van Gijsen H, Kotzé-Hörstmann L. Rat models of diet-induced obesity and metabolic dysregulation: Current trends, shortcomings and considerations for future research. Obes Res Clin Pract 2023; 17:449-457. [PMID: 37788944 DOI: 10.1016/j.orcp.2023.09.010] [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: 06/06/2023] [Revised: 08/18/2023] [Accepted: 09/18/2023] [Indexed: 10/05/2023]
Abstract
Rat diet-induced obesity and metabolic dysregulation (DIO/DIMD) is widely used as a pre-clinical model for human obesity and for testing weight-loss interventions. The aim of this review was to utilise a systematic literature survey of rat DIO/DIMD studies as a tool to document trends around study design and metabolic outcomes of these studies, and to consider ways in which the design of these studies may be improved to enhance the relevance thereof for human obesity research. In total, 110 comparisons between control and obesogenic dietary groups were included in the survey. Young male rats were found to be the model of choice, but fewer than 50% of studies provided comprehensive information about diet composition and energy intake. In addition, it was found that the majority of expected DIO/DIMD responses (hyperglycemia, hyperinsulinemia, dyslipidemia, hypoadiponectinemia) occurred at < 80% frequency, drawing into question the concept of a "typical" or "appropriate" response. We discuss the impact of differences in diet composition and energy intake on metabolic outcomes against the context of large heterogeneity of obesogenic diets employed in rat DIO/DIMD studies, and provide recommendations for the improvement of reporting standards around diet composition and dietary intake. In addition, we highlight the lack of data from female and older rats and describe considerations around the inclusion of sex and age as a variable in rat DIO/DIMD studies, aiming towards improving the applicability of these studies as a model of human obesity, which is most prevalent in women and older individuals.
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Affiliation(s)
- Hanél Sadie-Van Gijsen
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, PO Box 241, Cape Town 8000, South Africa.
| | - Liske Kotzé-Hörstmann
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, PO Box 241, Cape Town 8000, South Africa; Institute for Sport and Exercise Medicine (ISEM), Department of Sport Science, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, PO Box 241, Cape Town 8000, South Africa
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Kotzé-Hörstmann L, Cois A, Johnson R, Mabasa L, Shabalala S, Van Jaarsveld PJ, Sadie-Van Gijsen H. Characterization and Comparison of the Divergent Metabolic Consequences of High-Sugar and High-Fat Diets in Male Wistar Rats. Front Physiol 2022; 13:904366. [PMID: 35860656 PMCID: PMC9290519 DOI: 10.3389/fphys.2022.904366] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/27/2022] [Indexed: 12/12/2022] Open
Abstract
Diet-induced obesity (DIO) in laboratory rodents can serve as a model with which to study the pathophysiology of obesity, but obesogenic diets (high-sugar and/or high-fat) are often poorly characterised and simplistically aimed at inducing metabolic derangements for the purpose of testing the therapeutic capacity of natural products and other bioactive compounds. Consequently, our understanding of the divergent metabolic responses to different obesogenic diet formulations is limited. The aim of the present study was to characterise and compare differences in the metabolic responses induced by low-fat, medium-fat/high-sugar and high-fat diets in rats through multivariate statistical modelling. Young male Wistar rats were randomly assigned to CON (laboratory chow, low-fat), OB1 (high-sugar, medium-fat) or OB2 (high-fat) dietary groups (n = 24 each) for 17 weeks, after which metabolic responses were characterised. Projection-based multivariate analyses (principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA)) were used to explore the associations between measures of body composition and metabolism. Furthermore, we conducted a systematic literature survey to examine reporting trends in rat dietary intervention studies, and to determine how the metabolic responses observed in the present study compared to other recently published studies. The OB1 and OB2 dietary regimens resulted in distinct metabolic profiles, with OB1 characterised by perturbations in insulin homeostasis and adipose tissue secretory function, while OB2 was characterised by altered lipid and liver metabolism. This work therefore confirms, by means of direct comparison, that differences in dietary composition have a profound impact on metabolic and pathophysiological outcomes in rodent models of DIO. However, through our literature survey we demonstrate that dietary composition is not reported in the majority of rat dietary intervention studies, suggesting that the impact of dietary composition is often not considered during study design or data interpretation. This hampers the usefulness of such studies to provide enhanced mechanistic insights into DIO, and also limits the translatability of such studies within the context of human obesity.
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Affiliation(s)
- Liske Kotzé-Hörstmann
- Non-Communicable Diseases Research Unit, South African Medical Research Council, Cape Town, South Africa
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Annibale Cois
- Division of Health Systems and Public Health, Department of Global Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
- Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Rabia Johnson
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa
| | - Lawrence Mabasa
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa
| | - Samukelisiwe Shabalala
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa, South Africa
| | - Paul J. Van Jaarsveld
- Non-Communicable Diseases Research Unit, South African Medical Research Council, Cape Town, South Africa
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Hanél Sadie-Van Gijsen
- Centre for Cardio-metabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
- *Correspondence: Hanél Sadie-Van Gijsen,
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Asiedu B, Lembede BW, Nyakudya TT, Chivandi E. Orally administered zingerone does not mitigate alcohol-induced hepatic oxidative stress in growing Sprague Dawley rat pups. Drug Chem Toxicol 2022:1-10. [PMID: 35734876 DOI: 10.1080/01480545.2022.2085740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Neonatal alcohol exposure (NAE) can induce oxidative stress. We determined whether zingerone (ZO), a phytochemical with anti-oxidant activity, can mitigate the negative impact of neonatal alcohol-induced oxidative stress. Seventy ten-day-old Sprague-Dawley rat pups (35 male, 35 female) were randomly assigned and administered the following treatment regimens daily from postnatal day (PND) 12-21: group 1 - nutritive milk (NM), group 2 - NM +1 g/kg ethanol (Eth), group 3 - NM + 40 mg/kg ZO, group 4 - NM + Eth + ZO. Growth performance, blood glucose and plasma triglycerides (TGs), total cholesterol, HDL-cholesterol, leptin and insulin concentration were determined. Cytochrome p450E21(CYP2E1) and thiobarbituric acid (TBARS); markers of hepatic oxidative stress and catalase, superoxide dismutase (SOD) and total glutathione (GSH), anti-oxidant markers of the pups were determined. Oral administration of ethanol (NM + Eth), zingerone (NM + ZO) and combined ethanol and zingerone (NM + Eth + ZO) did not affect the growth performance and insulin and leptin concentration of the rats (p > 0.05). Ethanol significantly reduced plasma TGs concentration of female rats (p = 0.04 vs control). However, ethanol and/or its combination with zingerone decreased hepatic GSH (p = 0.02 vs control) and increased CYP2E1 (p = 0.0002 vs control) activity in male rat pups. Zingerone had no effect (p > 0.05 vs control) on the rats' CYP2E1, GSH, SOD and catalase activities. Neonatal alcohol administration elicited hepatic oxidative stress in male rat pups only, showing sexual dimorphism. Zingerone (NM + ZO) prevented an increase in CYP2E1 activity and a decrease in GSH concentration but did not prevent the alcohol-induced hepatic oxidative stress in the male rat pups.
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Affiliation(s)
- Bernice Asiedu
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa
| | - Busisani Wiseman Lembede
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa
| | - Trevor Tapiwa Nyakudya
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Gezina, South Africa
| | - Eliton Chivandi
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa
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Ajah AA, Lembede BW, Nkomozepi P, Erlwanger KH, Nyakudya TT. Neonatal Oral Administration of Chrysin Prevents Long-Term Development of Non-Alcoholic Fatty Liver Disease in a Sexually Dimorphic Manner in Fructose Nurtured Sprague Dawley Rats. Life (Basel) 2022; 12:life12060790. [PMID: 35743821 PMCID: PMC9225280 DOI: 10.3390/life12060790] [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: 03/31/2022] [Revised: 04/30/2022] [Accepted: 05/23/2022] [Indexed: 12/03/2022] Open
Abstract
High-fructose diets are linked with the development of non-alcoholic fatty liver disease (NAFLD), the management of which is a burden to society. Interventions with phytochemicals in the early postnatal period may prevent fructose-induced NAFLD later in adulthood. We investigated the protective potential of chrysin against fructose-induced NAFLD. Four-day-old male and female suckling Sprague Dawley rats (N = 112) were randomly grouped and orally gavaged daily with distilled water (negative Control-Cn + W), chrysin(Chr-100 mg/kg), fructose-solution (Fr-20% w/v), and Chr + Fr between postnatal day (PND) 4 and 21 and then weaned onto normal rat chow and plain drinking water to PND 55. From PND 56 to 130, half of the rats continued on plain water, and the rest had Fr as drinking fluid. Terminally, the liver tissue was collected, and the lipid content was determined and histologically assessed for NAFLD. Dietary Fr induced an increased hepatic lipid content (p = 0.0001 vs. Cn + W) both sexes, and it was only attenuated by neonatal Chr in female rats (p < 0.05). Histologically, there was increased microvesicular steatosis (p = 0.0001 vs. Cn + W) in both sexes, and it was prevented by neonatal Chr (p > 0.05). Fr caused macrovesicular steatosis (p = 0.01 vs. Cn + W) in females only, and chrysin did not prevent it (p > 0.05). Fr induced hepatocellular hypertrophy, and inflammation was observed in females only (p = 0.01 vs. Cn + W), and this was prevented by Chr (p > 0.05). The collagen area fraction was increased by Fr (p = 0.02 (males) and p = 0.04 (females) vs. Cn + W, respectively; however, chrysin did not prevent this (p > 0.05). Neonatal chrysin prevented some of the deleterious effects of the high-fructose diet on the liver, suggesting that chrysin should be further explored as a strategic prophylactic neonatal intervention against high-fructose-diet-induced NAFLD.
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Affiliation(s)
- Austin A. Ajah
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa; (B.W.L.); (K.H.E.)
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, University of Port Harcourt, P.M.B. 5323, Choba, Port Harcourt 500102, Nigeria
- Correspondence:
| | - Busisani W. Lembede
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa; (B.W.L.); (K.H.E.)
| | - Pilani Nkomozepi
- Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Corner Beit and Siemert Street, Doornfontein, Johannesburg 2094, South Africa; (P.N.); (T.T.N.)
| | - Kennedy H. Erlwanger
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa; (B.W.L.); (K.H.E.)
| | - Trevor T. Nyakudya
- Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Corner Beit and Siemert Street, Doornfontein, Johannesburg 2094, South Africa; (P.N.); (T.T.N.)
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Gezina, Pretoria 0031, South Africa
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Mohammed HM. Zingerone ameliorates non-alcoholic fatty liver disease in rats by activating AMPK. J Food Biochem 2022; 46:e14149. [PMID: 35338494 DOI: 10.1111/jfbc.14149] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/19/2022] [Accepted: 02/23/2022] [Indexed: 11/29/2022]
Abstract
This study was conducted to test the protective potential of Zingerone against a high-fat diet (HFD)-mediated non-alcoholic fatty liver disease (NAFLD) development in rats and examined in this protection is mediated modulating AMP-activated protein kinase (AMPK). Animals were segregated based on their diet and treatment into four groups (n = 6 each): (a) fed standard diet (STD), (b) treated with Zingerone (100 mg/kg), (c) fed HFD, (d) HFD + Zingerone (100 mg/kg), and (e) HFD + Zingerone (100 mg/kg) + compound c (CC) (an AMPK inhibitor) (0.2 mg/kg). The treatment with Zingerone attenuated the gain in final body weights, preserved liver structure, and downregulated the transcription of Bax and cleaved caspase-3. In the HFD and STD-fed rats, Zingerone reduced levels of fasting glucose and insulin and circulatory levels of cholesterol (CHOL) and triglycerides (TGs). Concomitantly, Zingerone enhanced glutathione (GSH) and superoxide dismutase (SOD) levels, depleted levels of malondialdehyde (MDA), and enhanced the nuclear levels of the nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, it lowered the levels of inflammatory cytokines and the nuclear levels of the nuclear factor kappa beta p65 (NF-κB p65). All these biochemical changes were associated with an increment in the phosphorylation of AMPK (p-AMPK) (activation) and reduced mRNA levels of SREBP1 and SREBP2. All observed effects afforded by Zingerone were abolished by CC. In conclusion, Zingerone prevents hepatic oxidative stress, inflammation, and apoptosis by activating AMPK. PRACTICAL APPLICATIONS: The findings of this study identified Zingerone, isolated from ginger, as a very effective drug that not only can attenuate fasting hyperglycemia and hyperlipidemia, but also prevent hepatic deposition, steatosis, and oxidative damage induced by high-fat-fed rats by activating the AMPK/Nrf2 antioxidant axis and concomitant suppression of SREBP1, SREBp2, and NF-κB p65. These data list Zingerone as a potent stimulator of AMPK which suggests an effective strategy to treat and alleviate NAFLD and encourages further translational and clinical trials.
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Affiliation(s)
- Heitham M Mohammed
- Department of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia
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