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Oliveira SCPD, Miyaguti NADS, Russell ST, Tobar N, Geraldo MV, Gomes-Marcondes MCC. Fish Oil Diet during Pre-mating, Gestation, and Lactation in Adult Offspring Rats on Cancer Cachexia Prevention. Mol Nutr Food Res 2021; 65:e2000863. [PMID: 33651486 DOI: 10.1002/mnfr.202000863] [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: 09/03/2020] [Revised: 02/18/2021] [Indexed: 11/11/2022]
Abstract
SCOPE Nutritional supplementation of the maternal diet can modify the cancer susceptibility in adult offspring. Therefore, the authors evaluate the effects of a fish-oil diet administered to a long-term, during pre-mating, gestation, and lactation, in reducing cancer-cachexia damages in adult Walker-256 tumor-bearing offspring. METHODS AND RESULTS Female rats receive control or fish oil diet during pre-mating, gestation, and lactation. After weaning, male offspring are fed the control diet until adulthood and distributed in (C) control adult-offspring; (W) adult tumor-bearing offspring; (OC) adult-offspring of maternal fish oil diet; (WOC) adult tumor-bearing offspring of maternal fish oil diet groups. Fat body mass is preserved, muscle expression of mechanistic target of rapamicin (mTOR) and eukariotic binding protein of eukariotic factor 4E (4E-BP1) is modified, being associated with lower 20S proteasome protein expression, and the liver alanine aminotransferase (ALT) enzyme content maintained in the WOC group. Also, the OC group shows reduced triglyceridemia. CONCLUSION In this experimental model of cachexia, the long-term maternal supplementation is a positive strategy to improve liver function and lipid metabolism, as well as to modify muscle proteins expression in the mTOR pathway and also reduce the 20S muscle proteasome protein, without altering the tumor development and muscle wasting in adult tumor-bearing offspring.
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Affiliation(s)
- Sarah Christine Pereira de Oliveira
- Laboratory of Nutrition and Cancer, Department of Structural and Functional Biology, Biology Institute, University of Campinas, Campinas, Brazil
| | - Natália Angelo da Silva Miyaguti
- Laboratory of Nutrition and Cancer, Department of Structural and Functional Biology, Biology Institute, University of Campinas, Campinas, Brazil
| | - Steven Thomas Russell
- School of Bioscience, College of Health and Life Sciences, Aston University, Birmingham, UK
| | - Natália Tobar
- Division of Nuclear Medicine, Department of Radiology, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Murilo Vieira Geraldo
- Laboratory of Cancer Cell Biology, Department of Structural and Functional Biology, Biology Institute, University of Campinas, Campinas, Brazil
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Martins AR, Crisma AR, Masi LN, Amaral CL, Marzuca-Nassr GN, Bomfim LH, Teodoro BG, Queiroz AL, Serdan TD, Torres RP, Mancini-Filho J, Rodrigues AC, Alba-Loureiro TC, Pithon-Curi TC, Gorjao R, Silveira LR, Curi R, Newsholme P, Hirabara SM. Attenuation of obesity and insulin resistance by fish oil supplementation is associated with improved skeletal muscle mitochondrial function in mice fed a high-fat diet. J Nutr Biochem 2018; 55:76-88. [DOI: 10.1016/j.jnutbio.2017.11.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/28/2017] [Accepted: 11/14/2017] [Indexed: 12/14/2022]
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3
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Yamashita AS, das Neves RX, Rosa-Neto JC, Lira FDS, Batista ML, Alcantara PS, Otoch JP, Seelaender M. White adipose tissue IFN-γ expression and signalling along the progression of rodent cancer cachexia. Cytokine 2017; 89:122-126. [PMID: 26987263 DOI: 10.1016/j.cyto.2016.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 02/27/2016] [Accepted: 02/29/2016] [Indexed: 12/11/2022]
Abstract
Cachexia is associated with increased morbidity and mortality in cancer. The White adipose tissue (WAT) synthesizes and releases several pro-inflammatory cytokines that play a role in cancer cachexia-related systemic inflammation. IFN-γ is a pleiotropic cytokine that regulates several immune and metabolic functions. To assess whether IFN-γ signalling in different WAT pads is modified along cancer-cachexia progression, we evaluated IFN-γ receptors expression (IFNGR1 and IFNGR2) and IFN-γ protein expression in a rodent model of cachexia (7, 10, and 14days after tumour implantation). IFN-γ protein expression was heterogeneously modulated in WAT, with increases in the mesenteric pad and decreased levels in the retroperitoneal depot along cachexia progression. Ifngr1 was up-regulated 7days after tumour cell injection in mesenteric and epididymal WAT, but the retroperitoneal depot showed reduced Ifngr1 gene expression. Ifngr2 gene expression was increased 7 and 14days after tumour inoculation in mesenteric WAT. The results provide evidence that changes in IFN-γ expression and signalling may be perceived at stages preceding refractory cachexia, and therefore, might be employed as a means to assess the early stage of the syndrome.
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Affiliation(s)
- Alex Shimura Yamashita
- Department of Physiology and Biophysics, Institute of Biomedical Sciences and Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil
| | - Rodrigo Xavier das Neves
- Cancer Metabolism Research Group, Institute of Biomedical Sciences and Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil
| | - José Cesar Rosa-Neto
- Cancer Metabolism Research Group, Institute of Biomedical Sciences and Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil
| | - Fábio Dos Santos Lira
- Immunometabolism Research Group, Department of Physical Education, Universidade Estadual Paulista (UNESP), Presidente Prudente, SP, Brazil
| | - Miguel Luís Batista
- Laboratory of Adipose Tissue Biology, Center for Integrated Biotechnology, University of Mogi das Cruzes, Mogi das Cruzes, São Paulo, Brazil
| | - Paulo Sérgio Alcantara
- Cancer Metabolism Research Group, Institute of Biomedical Sciences and Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil; Department of Clinical Surgery, University Hospital, University of Sao Paulo, São Paulo, Brazil
| | - José Pinhata Otoch
- Cancer Metabolism Research Group, Institute of Biomedical Sciences and Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil; Department of Clinical Surgery, University Hospital, University of Sao Paulo, São Paulo, Brazil
| | - Marília Seelaender
- Cancer Metabolism Research Group, Institute of Biomedical Sciences and Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil.
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Schiessel DL, Yamazaki RK, Kryczyk M, Coelho de Castro I, Yamaguchi AA, Pequito DCT, Brito GAP, Borghetti G, Aikawa J, Nunes EA, Naliwaiko K, Fernandes LC. Does Oil Rich in Alpha-Linolenic Fatty Acid Cause the Same Immune Modulation as Fish Oil in Walker 256 Tumor-Bearing Rats? Nutr Cancer 2016; 68:1369-1380. [DOI: 10.1080/01635581.2016.1224364] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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5
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de Sá RDCDC, Crisma AR, Cruz MM, Martins AR, Masi LN, do Amaral CL, Curi R, Alonso-Vale MIC. Fish oil prevents changes induced by a high-fat diet on metabolism and adipokine secretion in mice subcutaneous and visceral adipocytes. J Physiol 2016; 594:6301-6317. [PMID: 27558442 DOI: 10.1113/jp272541] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/22/2016] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS Fish oil (FO), rich in omega-3 polyunsaturated fatty acids, has beneficial effects on changes induced by obesity and partially prevents associated comorbidities. The effects of FO on adipocytes from different adipose tissue depots in high-fat (HF) diet induced obese mice have not been uninvestigated. This is the first study to examine the effects of FO on changes in metabolism and adipokine production in adipocytes from s.c. (inguinal; ING) or visceral (retroperitoneal; RP) white adipose depots in a HF diet-induced obese mice. Unlike most studies performed previously, FO supplementation was initiated 4 weeks before the induction of obesity. HF diet caused marked changes in ING (glucose uptake and secretion of adiponectin, tumour necrosis factor-α and interleukin-6 in ING) and RP (lipolysis, de novo lipogenesis and secretion of pro-inflammatory cytokines) adipose depots. Previous and concomitant FO administration prevented the changes in ING and RP adipocytes induced by the HF diet. ABSTRACT In the present study, we investigated the effect of fish oil (FO) on metabolism and adipokine production by adipocytes from s.c. (inguinal; ING) and visceral (retroperitoneal; RP) white adipose depots in high-fat (HF) diet-induced obese mice. Mice were divided into CO (control diet), CO+FO, HF and HF+FO groups. The HF group presented higher body weight, glucose intolerance, insulin resistance, higher plasma total and low-density lipoprotein cholesterol levels, and greater weights of ING and RP adipose depots accompanied by hypertrophy of the adipocytes. FO exerted anti-obesogenic effects associated with beneficial effects on dyslipidaemia and insulin resistance in mice fed a HF diet (HF+FO group). HF raised RP adipocyte lipolysis and the production of pro-inflammatory cytokines and reduced de novo synthesis of fatty acids, whereas, in ING adipocytes, it decreased glucose uptake and adiponectin secretion but did not change lipolysis. Therefore, the adipose depots play different roles in HF diet-induced insulin resistance according to their location in the body. Concerning cytokine secretion, adipocytes per se in addition to white adopise tissue infiltrated leukocytes have to be considered in the aetiology of the comorbidities associated with obesity. Evidence is presented showing that previous and concomitant administration of FO can prevent changes in metabolism and the secretion of hormones and cytokines in ING and RP adipocytes induced by HF.
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Affiliation(s)
- Roberta D C da Cunha de Sá
- Department of Biological Sciences, Institute of Environmental Sciences, Chemical and Pharmaceutical, Federal University of São Paulo, Diadema, Brazil
| | - Amanda R Crisma
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Maysa M Cruz
- Department of Biological Sciences, Institute of Environmental Sciences, Chemical and Pharmaceutical, Federal University of São Paulo, Diadema, Brazil
| | - Amanda R Martins
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Laureane N Masi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Catia L do Amaral
- Campus of Exact Science and Technology, State University of Goias, Anapolis, Brazil
| | - R Curi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Maria I C Alonso-Vale
- Department of Biological Sciences, Institute of Environmental Sciences, Chemical and Pharmaceutical, Federal University of São Paulo, Diadema, Brazil.
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Kumar A, Mastana SS, Lindley MR. EPA/DHA dietary supplementation attenuates exercise-induced bronchoconstriction in physically active asthmatic males. COGENT MEDICINE 2016. [DOI: 10.1080/2331205x.2016.1172696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Aishwarya Kumar
- Translational Chemical Biology Research Group, Human Cellular and Molecular Biology Research Laboratory, School of Sport Exercise and Health Sciences, Loughborough University, Loughborough, LE11 3TU, UK
- Clinical Trial Service Unit (CTSU) and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, 20 Roosevelt Drive, Oxford OX3 7LF, UK
| | - Sarabjit S. Mastana
- Translational Chemical Biology Research Group, Human Cellular and Molecular Biology Research Laboratory, School of Sport Exercise and Health Sciences, Loughborough University, Loughborough, LE11 3TU, UK
| | - Martin R. Lindley
- Translational Chemical Biology Research Group, Human Cellular and Molecular Biology Research Laboratory, School of Sport Exercise and Health Sciences, Loughborough University, Loughborough, LE11 3TU, UK
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Negi AK, Renuka, Bhatnagar A, Agnihotri N. Celecoxib and fish oil: a combination strategy for decreased inflammatory mediators in early stages of experimental mammary cancer. Inflammopharmacology 2016; 24:11-22. [PMID: 26749133 DOI: 10.1007/s10787-015-0259-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/23/2015] [Indexed: 12/27/2022]
Abstract
Chronic inflammation has been directly linked to cancer progression. Therefore, current study was designed to understand the mechanism of action of chemo-preventive effect of celecoxib and fish oil on inflammatory mediators in experimental mammary carcinoma. Female Wistar rats were distributed into control and DMBA treated groups and further subdivided based on pretreatment with celecoxib and/or fish oil. Inflammation was measured by assessing expression of NF-κB, COX-2 and cytokines. The results indicated an elevation in expression of NF-κB, COX-2 and cytokines' levels (IFN-γ, IL-4 and IL-10) in DMBA group as compared to controls. On pretreatment with celecoxib and/or fish oil in DMBA treated animals, a significant reduction in expression of NF-κB, COX-2 and cytokines' levels was observed. The decrease was more pronounced with combinatorial regimen than either celecoxib or fish oil alone. To conclude, a combinatorial strategy of celecoxib and fish oil may generate an immune response against the tumor cell by altering cytokine repertoire and decrease the tendency of tumor cells to escape immune surveillance.
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Affiliation(s)
- Anjana Kumari Negi
- Department of Biochemistry, Panjab University, Chandigarh, 160014, India
| | - Renuka
- Department of Biochemistry, Panjab University, Chandigarh, 160014, India
| | - Archana Bhatnagar
- Department of Biochemistry, Panjab University, Chandigarh, 160014, India
| | - Navneet Agnihotri
- Department of Biochemistry, Panjab University, Chandigarh, 160014, India.
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Amaral CL, Crisma AR, Masi LN, Martins AR, Hirabara SM, Curi R. DNA Methylation Changes Induced by a High-Fat Diet and Fish Oil Supplementation in the Skeletal Muscle of Mice. JOURNAL OF NUTRIGENETICS AND NUTRIGENOMICS 2015; 7:314-26. [PMID: 26022801 DOI: 10.1159/000381777] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/17/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To investigate the global changes in DNA methylation and methylation of the promoter region of the peroxisome proliferator-activated receptor gamma transcript variant 2 (Pparg2) gene resulting from a high-fat diet (HFD) and/or fish oil supplementation. METHODS Fish oil, rich in omega-3 polyunsaturated fatty acids, or water was orally administered to male mice for 12 weeks. After the first 4 weeks, the animals were fed a control diet or an HFD until the end of the experimental protocol, when the epididymal fat, gastrocnemius muscle and liver were excised. RESULTS Pparg2 mRNA expression was upregulated by obesity and downregulated by fish oil supplementation in the liver. In the gastrocnemius muscle, diet-induced obesity increased global DNA methylation. Fish oil prevented the decrease in Pparg2 promoter methylation induced by obesity in the gastrocnemius muscle. Regardless of the diet given, fish oil supplementation increased Pparg2 promoter methylation at CpG-263 in muscle and adipose tissue. CONCLUSION HFD and fish oil modified global and Pparg2 promoter DNA methylation in a tissue-specific manner. Fish oil supplementation attenuated body weight gain, abolished the increase in Pparg2 expression in the liver and prevented the decrease in Pparg2 promoter methylation in the muscle induced by the HFD.
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Affiliation(s)
- Catia L Amaral
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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9
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Schiessel DL, Yamazaki RK, Kryczyk M, Coelho I, Yamaguchi AA, Pequito DCT, Brito GAP, Borghetti G, Fernandes LC. α-Linolenic Fatty Acid Supplementation Decreases Tumor Growth and Cachexia Parameters in Walker 256 Tumor-Bearing Rats. Nutr Cancer 2015; 67:839-46. [DOI: 10.1080/01635581.2015.1043021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Miksza DR, de Souza CO, de Morais H, da Rocha AF, Borba-Murad GR, Bazotte RB, de Souza HM. Effect of infliximab on metabolic disorders induced by Walker-256 tumor in rats. Pharmacol Rep 2013; 65:960-9. [DOI: 10.1016/s1734-1140(13)71077-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 03/11/2013] [Indexed: 11/30/2022]
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The effectiveness of fish oil supplementation in asthmatic rats is limited by an inefficient action on ASM function. Lipids 2013; 48:889-97. [PMID: 23743575 DOI: 10.1007/s11745-013-3804-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 05/14/2013] [Indexed: 01/20/2023]
Abstract
Episodes of acute exacerbation are the major clinical feature of asthma and therefore represent an important focus for developing novel therapies for this disease. There are many reports that the n-3 fatty acids found in fish oil exert anti-inflammatory effects, but there are few studies of the action of fish oil on airway smooth muscle (ASM) function. In the present investigation, we evaluated the effect of fish oil supplementation on smooth muscle force of contraction in ovalbumin-induced asthmatic Wistar rats, and its consequences on static lung compliance, mucus production, leukocyte chemotaxis and production of proinflammatory cytokines. Fish oil supplementation suppressed the infiltration of inflammatory cells into the lung in asthmatic animals (2.04 ± 0.19 × 10(6) cells vs. 3.33 ± 0.43 × 10(6) cells in the control asthmatic group; P < 0.05). Static lung compliance increased with fish oil supplementation in asthmatic rats (0.640 ± 0.053 mL/cm H2O vs. 0.399 ± 0.043 mL/cm H2O; P < 0.05). However, fish oil did not prevent asthma-associated lung eosinophilia and did not affect the concentrations of tumor necrosis factor-α and interleukin-1β in lung tissue or the proportion of the airways obliterated with mucus. Fish oil had no effect on the force of contraction in asthmatic rats in response to acetylcholine (3.026 ± 0.274 mN vs. 2.813 ± 0.364 mN in the control asthmatic group). In conclusion, although fish oil exerts some benefits in this model of asthma, its effectiveness appears to be limited by an inefficient action on airway smooth muscle function.
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Dreifuss AA, Bastos-Pereira AL, Fabossi IA, Lívero FADR, Stolf AM, Alves de Souza CE, Gomes LDO, Constantin RP, Furman AEF, Strapasson RLB, Teixeira S, Zampronio AR, Muscará MN, Stefanello MEA, Acco A. Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity. PLoS One 2013; 8:e54618. [PMID: 23408945 PMCID: PMC3567083 DOI: 10.1371/journal.pone.0054618] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 12/13/2012] [Indexed: 11/23/2022] Open
Abstract
This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT) brute hydroethanolic (BHE) extract with those of two fractions derived from it. These fractions are choroformic (CHCl3) and n-butanolic (BuOH), rich in pentacyclic oxindole alkaloids (POA) and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg(-1)) or its fractions (as per the yield of the fractioning process) or vehicle (Control) was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-α level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-α level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Alexandra Acco
- Pharmacology Department, Federal University of Paraná, Brazil
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Hirabara SM, Folador A, Fiamoncini J, Lambertucci RH, Rodrigues CF, Rocha MS, Aikawa J, Yamazaki RK, Martins AR, Rodrigues AC, Carpinelli AR, Pithon-Curi TC, Fernandes LC, Gorjão R, Curi R. Fish oil supplementation for two generations increases insulin sensitivity in rats. J Nutr Biochem 2012; 24:1136-45. [PMID: 23246156 DOI: 10.1016/j.jnutbio.2012.08.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 08/13/2012] [Accepted: 08/20/2012] [Indexed: 11/26/2022]
Abstract
We investigated the effect of fish oil supplementation for two consecutive generations on insulin sensitivity in rats. After the nursing period (21 days), female rats from the same prole were divided into two groups: (a) control group and (b) fish oil group. Female rats were supplemented with water (control) or fish oil at 1 g/kg body weight as a single bolus for 3 months. After this period, female rats were mated with male Wistar rats fed on a balanced chow diet (not supplemented). Female rats continued to receive supplementation throughout gestation and lactation periods. The same treatment was performed for the next two generations (G1 and G2). At 75 days of age, male offspring from G1 and G2 generations from both groups were used in the experiments. G1 rats did not present any difference with control rats. However, G2 rats presented reduction in glycemia and lipidemia and improvement in in vivo insulin sensitivity (model assessment of insulin resistance, insulin tolerance test) as well as in vitro insulin sensitivity in soleus muscle (glucose uptake and metabolism). This effect was associated with increased insulin-stimulated p38 MAP kinase phosphorylation and lower n-6/n-3 fatty acid ratio, but not with activation of proteins from insulin signaling (IR, IRS-1 and Akt). Global DNA methylation was decreased in liver but not in soleus muscle. These results suggest that long-term fish oil supplementation improves insulin sensitivity in association with increased insulin-stimulated p38 activation and decreased n-6:n-3 ratio in skeletal muscle and decreased global DNA methylation in liver.
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Affiliation(s)
- Sandro M Hirabara
- Institute of Physical Activity Sciences and Sport, Cruzeiro do Sul University, São Paulo, Brazil.
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Fonseca EAI, de Oliveira MA, Lobato NDS, Akamine EH, Colquhoun A, de Carvalho MHC, Zyngier SB, Fortes ZB. Metformin reduces the stimulatory effect of obesity on in vivo Walker-256 tumor development and increases the area of tumor necrosis. Life Sci 2011; 88:846-52. [PMID: 21439974 DOI: 10.1016/j.lfs.2011.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/11/2011] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
Abstract
AIMS The objective of this study was to analyze the influence of obesity and insulin resistance on tumor development and, in turn, the effect of insulin sensitizing agents. MAIN METHODS Male offspring of Wistar rats received monosodium glutamate (400mg/kg) (obese) or saline (control) from the second to sixth day after birth. Sixteen-week-old control and obese rats received 5×10(5) Walker-256 tumor cells, subcutaneously injected into the right flank. Some of the obese and control rats received concomitant treatment with metformin (300mg/kg) by gavage. At the 18th week, obesity was characterized. The percentage of rats that developed tumors, the tumor relative weight and the percentage of cachexia incidence were analyzed. The tumor tissue was evaluated histologically by means of hematoxylin and eosin staining. KEY FINDINGS Metformin did not correct the insulin resistance in obese rats. The tumor development was significantly higher in the obese group, whereas metformin treatment reduced it. After pathological analysis, we observed that the tumor tissues were similar in all groups except for adipocytes, which were found in greater quantity in the obese and metformin-treated obese groups. The area of tumor necrosis was higher in the group treated with metformin when compared with the untreated one. SIGNIFICANCE Metformin reduced Walker-256 tumor development but not cachexia in obese rats. The reduction occurred independently of the correction of insulin resistance. Metformin increased the area of necrosis in tumor tissues, which may have contributed to the reduced tumor development.
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