Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos

Detalhes bibliográficos
Autor(a) principal: Rocha, Vanessa da Silva
Data de Publicação: 2015
Tipo de documento: Dissertação
Idioma: por
Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
Texto Completo: http://repositorio.ufes.br/handle/10/7288
Resumo: Obesity is a metabolic chronic disease characterized by excessive accumulation of body fat and an independent risk factor for development of cardiovascular disorders. Experimental studies show that the unsaturated high-fat diet-induced obesity promotes vascular alterations characterized by improved endothelial L-arginine/Nitric Oxide (NO) pathway. Research suggest that leptin is involved in this process, being able to promote vasodilation by increase of NO synthesis and/or release. The objective of this study was to evaluate the involvement of leptin on vascular reactivity in aortic rings of rats submitted to obesity by unsaturated high-diet fat. Thirty-day-old male Wistar rats were randomized into two groups: control (C, n=9) and obese (Ob, n=7). The C group was fed a standard diet and the Ob group was alternately submitted to four palatable high-fat diets for 27 weeks. Final body weight, total body fat and adiposity index were assessed. The glycemic profile was evaluated by glucose tolerance test (GTT) and systolic blood pressure (SBP) by tailcuff plethysmography method. The analysis of vascular reactivity was carried out in aortic segments and assessed by the concentration-response curves to phenylephrine (10-11 to 3x10-4 M), acetylcholine (10-12 to 10-4 M) and leptin (10-14 to 3x10-6 M) in the presence and absence of L-NAME (nonspecific inhibitor of NO synthase, 100 µM). Data were expressed using descriptive measures of variability position and submitted to Students T-test and two-way ANOVA followed by a Bonferroni post-hoc test. The level of significance was considered to be 5%. The results show that unsaturated high-fat diet used in this study promoted greater calorie intake, elevation of body weight and body fat, adiposity index, featuring a reproducible model of obesity. However, comorbidities frequently associated to experimental obesity were not visualized, such as glucose intolerance, dyslipidemia and hypertension. Obesity reduced the maximum response to phenylephrine (Rmax - C: 88.5 ± 4.8% vs Ob: 61.1 ± 5.4%*; p<0.05) and sensibility (pD2 - C: -6.78 ± 0.10 vs Ob: -7.31 ± 0.12 *; p<0.05). After incubation of aortic rings with L-NAME, in Ob group persisted significant decrease in pD2 (L-NAME/C: -7.41 ± 0.13 vs L-NAME/Ob: -7.80 ± 0.10# ; p<0.05) than C. Obesity lead did not change the vasodilation induced by acetylcholine between groups. However, after administration of L-NAME, the Rmax (L-NAME/Ob: 4.10 ± 1.89%# vs L-NAME/C: 26.54 ± 5.30%; p<0.05) was lower in the Ob group compared to C. Furthermore, the vasodilation induced by leptin in the presence and absence of L-NAME were not altered by obesity. In conclusion, obesity induced unsaturated fat diet leads to decreased contractile response without changing the vasodilator response. Furthermore, the findings show that leptininduced relaxation response is not altered due to the obesity, but are dependent on the release of NO.
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spelling Cunha, Márcia Regina Holanda daLeopoldo, André SoaresRocha, Vanessa da SilvaFerreira, Lucas GuimarãesMauad, Hélder2018-08-01T21:36:33Z2018-08-012018-08-01T21:36:33Z2015-06-25Obesity is a metabolic chronic disease characterized by excessive accumulation of body fat and an independent risk factor for development of cardiovascular disorders. Experimental studies show that the unsaturated high-fat diet-induced obesity promotes vascular alterations characterized by improved endothelial L-arginine/Nitric Oxide (NO) pathway. Research suggest that leptin is involved in this process, being able to promote vasodilation by increase of NO synthesis and/or release. The objective of this study was to evaluate the involvement of leptin on vascular reactivity in aortic rings of rats submitted to obesity by unsaturated high-diet fat. Thirty-day-old male Wistar rats were randomized into two groups: control (C, n=9) and obese (Ob, n=7). The C group was fed a standard diet and the Ob group was alternately submitted to four palatable high-fat diets for 27 weeks. Final body weight, total body fat and adiposity index were assessed. The glycemic profile was evaluated by glucose tolerance test (GTT) and systolic blood pressure (SBP) by tailcuff plethysmography method. The analysis of vascular reactivity was carried out in aortic segments and assessed by the concentration-response curves to phenylephrine (10-11 to 3x10-4 M), acetylcholine (10-12 to 10-4 M) and leptin (10-14 to 3x10-6 M) in the presence and absence of L-NAME (nonspecific inhibitor of NO synthase, 100 µM). Data were expressed using descriptive measures of variability position and submitted to Students T-test and two-way ANOVA followed by a Bonferroni post-hoc test. The level of significance was considered to be 5%. The results show that unsaturated high-fat diet used in this study promoted greater calorie intake, elevation of body weight and body fat, adiposity index, featuring a reproducible model of obesity. However, comorbidities frequently associated to experimental obesity were not visualized, such as glucose intolerance, dyslipidemia and hypertension. Obesity reduced the maximum response to phenylephrine (Rmax - C: 88.5 ± 4.8% vs Ob: 61.1 ± 5.4%*; p<0.05) and sensibility (pD2 - C: -6.78 ± 0.10 vs Ob: -7.31 ± 0.12 *; p<0.05). After incubation of aortic rings with L-NAME, in Ob group persisted significant decrease in pD2 (L-NAME/C: -7.41 ± 0.13 vs L-NAME/Ob: -7.80 ± 0.10# ; p<0.05) than C. Obesity lead did not change the vasodilation induced by acetylcholine between groups. However, after administration of L-NAME, the Rmax (L-NAME/Ob: 4.10 ± 1.89%# vs L-NAME/C: 26.54 ± 5.30%; p<0.05) was lower in the Ob group compared to C. Furthermore, the vasodilation induced by leptin in the presence and absence of L-NAME were not altered by obesity. In conclusion, obesity induced unsaturated fat diet leads to decreased contractile response without changing the vasodilator response. Furthermore, the findings show that leptininduced relaxation response is not altered due to the obesity, but are dependent on the release of NO.A obesidade é uma doença crônica metabólica caracterizada pelo acúmulo excessivo de gordura corporal e fator de risco independente para o desenvolvimento de distúrbios cardiovasculares. Estudos experimentais mostram que a indução à obesidade por dieta hiperlipídica insaturada promove alteração vascular caracterizada por melhora na via endotelial L-arginina/Óxido Nítrico (NO). Pesquisas sugerem que a leptina está envolvida nesse processo, sendo capaz de promover vasodilatação pelo aumento da síntese e/ou liberação do NO. O objetivo deste trabalho foi avaliar o envolvimento da leptina na reatividade vascular em anéis de aorta de ratos submetidos à obesidade por meio de dieta com alto teor de gordura insaturada. Ratos Wistar com 30 dias de idade foram randomizados em dois grupos: controle (C, n=9) e obeso (Ob, n=7). Os ratos C receberam dieta padrão e os Ob um ciclo de dietas hiperlipídicas insaturadas alternadas diariamente por 27 semanas. Foram analisados o peso corporal final, a gordura corporal total e o índice de adiposidade. O perfil glicêmico foi avaliado pelo teste de tolerância à glicose (GTT) e a pressão arterial sistólica (PAS) por pletismografia de cauda. A análise da reatividade vascular foi realizada em anéis de aorta e avaliada por meio de curvas concentração-resposta à fenilefrina (10-11 a 3x10-4 M), acetilcolina (10-12 a 10-4 M) e leptina (10-14 a 3x10-6 M) na ausência e na presença de L-NAME (inibidor da síntese de óxido nítrico; 100 μM). Os dados obtidos foram expressos por meio de medidas descritivas de posição e variabilidade e submetidos ao teste t de Student e análise de variância (ANOVA) de duas vias com teste post-hoc de Bonferroni. O nível de significância considerado foi de 5%. Os resultados mostram que a dieta hiperlipídica insaturada utilizada neste estudo acarretou maior ingestão calórica, elevação do peso e gordura corporal, índice de adiposidade, caracterizando um modelo reprodutível de obesidade. No entanto, não foram visualizadas comorbidades frequentemente associadas com a obesidade experimental, como intolerância à glicose, dislipidemia e hipertensão arterial. A obesidade reduziu a resposta máxima de contração à fenilefrina (Rmáx - C: 88,5 ± 4,8% vs Ob: 61,1 ± 5,4%*; p<0,05) e a sensibilidade (pD2 - C: -6,78 ± 0,10 vs Ob: -7,31 ± 0,12*; p<0,05). Após incubação dos anéis de aorta com L-NAME, nos animais Ob persistiu a diminuição significativa na pD2 (L-NAME/C: -7,41 ± 0,13 vs L-NAME/Ob: -7,80 ± 0,10# ; p<0,05) quando comparados ao C. A obesidade não modificou a vasodilatação induzida pela acetilcolina entre os grupos. Entretanto, após administração do L-NAME, a Rmáx (LNAME/Ob: 4,10 ± 1,89%# vs L-NAME/C: 26,54 ± 5,30%; p<0,05) foi menor no grupo Ob quando comparado ao grupo C. Além disso, a vasodilatação induzida pela leptina na presença e ausência de L-NAME não foram alteradas pela obesidade. Em conclusão, a obesidade induzida por dieta hiperlipídica insaturada acarreta diminuição da resposta contrátil sem alteração da resposta vasodilatadora. Além disso, os achados evidenciam que as respostas relaxantes induzidas pela leptina não está alterada em função da obesidade, mas são dependentes da liberação do NO.Texthttp://repositorio.ufes.br/handle/10/7288porUniversidade Federal do Espírito SantoMestrado em Educação FísicaPrograma de Pós-Graduação em Educação FísicaUFESBRCentro de Educação Física e DesportosObesityHigh-fat dietEndotheliumLeptinDieta hiperlipídicaAortaObesidadeDieta hiperlipídicaEndotélioLeptinaLipídios - MetabolismoEducação Física796Influência da leptina na reatividade vascular em anéis de aorta de ratos obesosinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)instname:Universidade Federal do Espírito Santo (UFES)instacron:UFESORIGINALtese_8931_Dissertação Vanessa da Silva.pdfapplication/pdf1356448http://repositorio.ufes.br/bitstreams/23a45a69-fa87-44fe-944b-b44dfaa1bdc4/download45469d1edff4990fd37447ce0d3ffcc2MD5110/72882024-07-16 19:11:21.857oai:repositorio.ufes.br:10/7288http://repositorio.ufes.brRepositório InstitucionalPUBhttp://repositorio.ufes.br/oai/requestopendoar:21082024-10-15T17:55:57.840661Repositório Institucional da Universidade Federal do Espírito Santo (riUfes) - Universidade Federal do Espírito Santo (UFES)false
dc.title.none.fl_str_mv Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
title Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
spellingShingle Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
Rocha, Vanessa da Silva
Obesity
High-fat diet
Endothelium
Leptin
Dieta hiperlipídica
Aorta
Obesidade
Dieta hiperlipídica
Endotélio
Leptina
Educação Física
Lipídios - Metabolismo
796
title_short Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
title_full Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
title_fullStr Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
title_full_unstemmed Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
title_sort Influência da leptina na reatividade vascular em anéis de aorta de ratos obesos
author Rocha, Vanessa da Silva
author_facet Rocha, Vanessa da Silva
author_role author
dc.contributor.advisor-co1.fl_str_mv Cunha, Márcia Regina Holanda da
dc.contributor.advisor1.fl_str_mv Leopoldo, André Soares
dc.contributor.author.fl_str_mv Rocha, Vanessa da Silva
dc.contributor.referee1.fl_str_mv Ferreira, Lucas Guimarães
dc.contributor.referee2.fl_str_mv Mauad, Hélder
contributor_str_mv Cunha, Márcia Regina Holanda da
Leopoldo, André Soares
Ferreira, Lucas Guimarães
Mauad, Hélder
dc.subject.eng.fl_str_mv Obesity
High-fat diet
Endothelium
Leptin
Dieta hiperlipídica
topic Obesity
High-fat diet
Endothelium
Leptin
Dieta hiperlipídica
Aorta
Obesidade
Dieta hiperlipídica
Endotélio
Leptina
Educação Física
Lipídios - Metabolismo
796
dc.subject.por.fl_str_mv Aorta
Obesidade
Dieta hiperlipídica
Endotélio
Leptina
dc.subject.cnpq.fl_str_mv Educação Física
dc.subject.br-rjbn.none.fl_str_mv Lipídios - Metabolismo
dc.subject.udc.none.fl_str_mv 796
description Obesity is a metabolic chronic disease characterized by excessive accumulation of body fat and an independent risk factor for development of cardiovascular disorders. Experimental studies show that the unsaturated high-fat diet-induced obesity promotes vascular alterations characterized by improved endothelial L-arginine/Nitric Oxide (NO) pathway. Research suggest that leptin is involved in this process, being able to promote vasodilation by increase of NO synthesis and/or release. The objective of this study was to evaluate the involvement of leptin on vascular reactivity in aortic rings of rats submitted to obesity by unsaturated high-diet fat. Thirty-day-old male Wistar rats were randomized into two groups: control (C, n=9) and obese (Ob, n=7). The C group was fed a standard diet and the Ob group was alternately submitted to four palatable high-fat diets for 27 weeks. Final body weight, total body fat and adiposity index were assessed. The glycemic profile was evaluated by glucose tolerance test (GTT) and systolic blood pressure (SBP) by tailcuff plethysmography method. The analysis of vascular reactivity was carried out in aortic segments and assessed by the concentration-response curves to phenylephrine (10-11 to 3x10-4 M), acetylcholine (10-12 to 10-4 M) and leptin (10-14 to 3x10-6 M) in the presence and absence of L-NAME (nonspecific inhibitor of NO synthase, 100 µM). Data were expressed using descriptive measures of variability position and submitted to Students T-test and two-way ANOVA followed by a Bonferroni post-hoc test. The level of significance was considered to be 5%. The results show that unsaturated high-fat diet used in this study promoted greater calorie intake, elevation of body weight and body fat, adiposity index, featuring a reproducible model of obesity. However, comorbidities frequently associated to experimental obesity were not visualized, such as glucose intolerance, dyslipidemia and hypertension. Obesity reduced the maximum response to phenylephrine (Rmax - C: 88.5 ± 4.8% vs Ob: 61.1 ± 5.4%*; p<0.05) and sensibility (pD2 - C: -6.78 ± 0.10 vs Ob: -7.31 ± 0.12 *; p<0.05). After incubation of aortic rings with L-NAME, in Ob group persisted significant decrease in pD2 (L-NAME/C: -7.41 ± 0.13 vs L-NAME/Ob: -7.80 ± 0.10# ; p<0.05) than C. Obesity lead did not change the vasodilation induced by acetylcholine between groups. However, after administration of L-NAME, the Rmax (L-NAME/Ob: 4.10 ± 1.89%# vs L-NAME/C: 26.54 ± 5.30%; p<0.05) was lower in the Ob group compared to C. Furthermore, the vasodilation induced by leptin in the presence and absence of L-NAME were not altered by obesity. In conclusion, obesity induced unsaturated fat diet leads to decreased contractile response without changing the vasodilator response. Furthermore, the findings show that leptininduced relaxation response is not altered due to the obesity, but are dependent on the release of NO.
publishDate 2015
dc.date.issued.fl_str_mv 2015-06-25
dc.date.accessioned.fl_str_mv 2018-08-01T21:36:33Z
dc.date.available.fl_str_mv 2018-08-01
2018-08-01T21:36:33Z
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Mestrado em Educação Física
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publisher.none.fl_str_mv Universidade Federal do Espírito Santo
Mestrado em Educação Física
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