Aerobic physical training impact on adipokines in women with polycystic ovary syndrome - Effects of body fat percentage

ABSTRACT Objective: We investigated the effects of aerobic training on adipokine concentrations in women with polycystic ovary syndrome (PCOS). Subjects and methods: 120 women, including 60 with PCOS and 60 without PCOS, were divided into six groups (n = 20) based on body fat percentages of 22%-27%, 28%-32%, and 33%-37%. All groups were submitted the same evaluations before and after 16 weeks of aerobic training. These included anthropometric and hemodynamic analyses, cardiopulmonary tests, and laboratory tests. Two-way analysis of variance was performed to evaluate the differences between women with and without PCOS, effect of the body fat percentage, and effect of aerobic training. Results: Body fat and PCOS were associated with high values of blood glucose, insulin, and testosterone. Body fat also reduced adiponectin levels and increased leptin, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). In contrast, the PCOS increased only TNF-α and IL-6 levels. In the PCOS group, aerobic training reduced insulin, triglycerides, leptin, and IL-6 levels. It also promoted an increase in adiponectin and high-density lipoprotein levels. However, aerobic training did not alter TNF-α concentrations. Conclusion: The body fat potentiates metabolic impairments that may be harmful to women with PCOS. Aerobic training appears to promote an important beneficial effect on the metabolic regulation of adipokines, except TNF-α.

Increased airway resistance can be related to the decrease in the functional capacity in obese women.

BACKGROUND AND OBJECTIVE: Obesity can increase the airways resistance, mainly in the periphery, leading to dyspnea perception that can impair the functional capacity. This study aimed to analyze if airways resistance could be related to the walking capacity of women with morbid obesity. METHODS: Thirty-seven women with grade III obesity in preoperative bariatric surgery were evaluated using the spirometry test, impulse oscillometry system (IOS), and six-minute walk test (6MWT). Additionally, data about their daily dyspnea perception and physical activity level were collected. RESULTS: Variables of the spirometry test did not detect ventilator disorders. Compared to the predicted values, the IOS identified significant increase in airways resistance (kPa/L/s) (R5: 0.36 (0.34; 0.36) and 0.53 (0.47; 0.61); R20: 0.30 (0.28; 0.30) and 0.41 (0.35; 0.45); R5-20: 0.06 (0.06; 0.06) and 0.14 (0.10; 0.15); X5: -0.03 (-0.04; -0.01) and -0.20 (-0.27; -0.18), respectively). The distance walked in the 6MWT, 491.4±60.4m was significantly correlated to R5 (rho = -0.41, p = 0.01), R5-20 (rho = -0.52, p = 0.001), and X5 (rho = 0.54, p = 0.0006). CONCLUSION: The IOS is able to identify changes in airway resistance even before the onset of symptoms. When evaluated by IOS women with severe obesity and normal spirometry exhibited central and peripheral airways obstruction. The correlations between the IOS and six-minute walk distance suggest that increased peripheral airways resistance could be related to worsening functional capacity.

Effects of Controlled Voluntary Increase in the Ventilatory Demand on Respiratory System Resistance in Healthy and Non-Cystic Fibrosis Bronchiectasis Subjects: A Cross-Sectional Study.

INTRODUCTION: Bronchiectasis patients may present a reduced functional capacity due to an increase in the ventilatory demand during exercise. OBJECTIVE: To evaluate the effects of controlled voluntary hyperinflation and increased respiratory rate on the mechanics of the respiratory system, simulating what happens during exercise, in bronchiectasis and healthy subjects. METHODS: Bronchiectasis (n=30) and healthy (n=16) subjects were evaluated by impulse oscillometry (IOS) during a baseline condition, and in controlled conditions with baseline (b) tidal volume (V) and hyperinflation (H), with respiratory rates at 30(R30) and 40(R40) bpm, in a random order. The mixed effects and a significance level at 0.05 were used for comparisons. RESULTS: Resistance at 5Hz (R5), and at minus 20Hz (R5-R20), in kPa/L/s, were higher in subjects with bronchiectasis in all experimental conditions (p<0.05). For the bronchiectasis group, R5 and R5-20 increased with R increase at V (VRb versus VR30 and VR40; VR30 versus VR40; R5, R20 and R5-20 increased with R increase at H (HRb versus HR40; HR30 versus HR40). For the same R, there was a decrease with H compared to V (HRb versus VR30 and VR40; and HR30 versus VR30 and VR40). For the healthy group, only R20 showed differences (HR30 versus HR40; HR40 versus VR40). CONCLUSION: The tachypnea increases the resistance and reactance of the respiratory system in bronchiectasis patients, and the voluntary hyperinflation caused attenuates this increase. These results can guide the development of strategies to reduce the limitation of physical activity in patients with bronchiectasis.

Effects of Controlled Voluntary Increase in the Ventilatory Demand on Respiratory System Resistance in Healthy and Non-Cystic Fibrosis Bronchiectasis Subjects: A Cross-Sectional Study.

INTRODUCTION: Bronchiectasis patients may present a reduced functional capacity due to an increase in the ventilatory demand during exercise. OBJECTIVE: To evaluate the effects of controlled voluntary hyperinflation and increased respiratory rate on the mechanics of the respiratory system, simulating what happens during exercise, in bronchiectasis and healthy subjects. METHODS: Bronchiectasis (n=30) and healthy (n=16) subjects were evaluated by impulse oscillometry (IOS) during a baseline condition, and in controlled conditions with baseline (b) tidal volume (V) and hyperinflation (H), with respiratory rates at 30(R30) and 40(R40) bpm, in a random order. The mixed effects and a significance level at 0.05 were used for comparisons. RESULTS: Resistance at 5Hz (R5), and at minus 20Hz (R5-R20), in kPa/L/s, were higher in subjects with bronchiectasis in all experimental conditions (p<0.05). For the bronchiectasis group, R5 and R5-20 increased with R increase at V (VRb versus VR30 and VR40; VR30 versus VR40; R5, R20 and R5-20 increased with R increase at H (HRb versus HR40; HR30 versus HR40). For the same R, there was a decrease with H compared to V (HRb versus VR30 and VR40; and HR30 versus VR30 and VR40). For the healthy group, only R20 showed differences (HR30 versus HR40; HR40 versus VR40). CONCLUSION: The tachypnea increases the resistance and reactance of the respiratory system in bronchiectasis patients, and the voluntary hyperinflation caused attenuates this increase. These results can guide the development of strategies to reduce the limitation of physical activity in patients with bronchiectasis.

Polycystic ovary syndrome associated with increased adiposity interferes with serum levels of TNF-alpha and IL-6 differently from leptin and adiponectin.

Objective The aim of this study was to investigate polycystic ovary syndrome (PCOS) and to explore the relationship between body fat percentage and metabolic markers. Subjects and methods Sedentary women were assigned to PCOS (N = 60) and CONTROL (N = 60) groups. Each group was subdivided into three subgroups according to body fat percentage (22-27%, 27-32% and 32-37%). The protocol consisted of assessments of glucose, insulin, androgens, follicle stimulating hormone (FSH), luteinizing hormone (LH), 17-hydroxyprogesterone (17-OHP), leptin, adiponectin, tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). Results The PCOS subgroups showed higher concentrations of androgens, LH and 17-OHP. Leptin showed direct relationship with increased body fat percentage, whereas adiponectin showed the inverse effect. However, both were unaffected by PCOS. TNF-α and IL-6 were higher in PCOS women and showed a direct relationship with increased body fat percentage. Glucose showed direct relationship with body fat percentage, whereas insulin presented higher values in PCOS women and direct relationship with increased body fat percentage. Conclusions Our findings indicate that PCOS and body fat percentage directly influence concentrations of insulin, TNF-α and IL-6, whereas leptin and adiponectin are influenced only by the increase in body fat percentage in these women. Arch Endocrinol Metab. 2020;64(1):4-10.

Polycystic ovary syndrome associated with increased adiposity interferes with serum levels of TNF-alpha and IL-6 differently from leptin and adiponectin

ABSTRACT Objective The aim of this study was to investigate polycystic ovary syndrome (PCOS) and to explore the relationship between body fat percentage and metabolic markers. Subjects and methods Sedentary women were assigned to PCOS (N = 60) and CONTROL (N = 60) groups. Each group was subdivided into three subgroups according to body fat percentage (22-27%, 27-32% and 32-37%). The protocol consisted of assessments of glucose, insulin, androgens, follicle stimulating hormone (FSH), luteinizing hormone (LH), 17-hydroxyprogesterone (17-OHP), leptin, adiponectin, tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). Results The PCOS subgroups showed higher concentrations of androgens, LH and 17-OHP. Leptin showed direct relationship with increased body fat percentage, whereas adiponectin showed the inverse effect. However, both were unaffected by PCOS. TNF-α and IL-6 were higher in PCOS women and showed a direct relationship with increased body fat percentage. Glucose showed direct relationship with body fat percentage, whereas insulin presented higher values in PCOS women and direct relationship with increased body fat percentage. Conclusions Our findings indicate that PCOS and body fat percentage directly influence concentrations of insulin, TNF-α and IL-6, whereas leptin and adiponectin are influenced only by the increase in body fat percentage in these women. Arch Endocrinol Metab. 2020;64(1):4-10

Women with Polycystic Ovarian Syndrome Exhibit Reduced Baroreflex Sensitivity That May Be Associated with Increased Body Fat / Mulheres com Síndrome do Ovário Policístico Apresentam menor Sensibilidade Barorreflexa, a Qual Pode Estar Associada ao Aumento da Gordura Corporal

Abstract Background: Polycystic ovarian syndrome (PCOS) women have a high prevalence of obesity and alterations in cardiovascular autonomic control, mainly modifications in heart rate variability (HRV) autonomic modulation. However, there are few studies about other autonomic control parameters, such as blood pressure variability (BPV) and baroreflex sensitivity (BRS). In addition, there are still doubts about the obesity real contribution in altering autonomic control in these women. Objective: To investigate BPV and BRS autonomic modulation alterations in PCOS women, as well as, to evaluate whether these alterations are due PCOS or increased body fat. Methods: We studied 30 eutrophic volunteers [body mass index (BMI) < 25 kg/m2] without PCOS (control group) and 60 volunteers with PCOS divided into: eutrophic (BMI < 25 kg/m2, N = 30) and obese women (BMI > 30 kg/m2, N = 30). All volunteers were submitted to anthropometric evaluation, hemodynamic and cardiorespiratory parameters record at rest and during physical exercise, analysis of HRV, BPV and spontaneous BRS. The differences in p less than 5% (p < 0.05) were considered statistically significant. Results: Related to eutrophics groups, there were no differences in autonomic parameters evaluated. The comparison between the PCOS groups showed that both PCOS groups did not differ in the BPV analysis. Although, the obese PCOS group presented lower values of spontaneous BRS and HRV, in low frequency and high frequency oscillations in absolute units. Conclusion: Our results suggest that obesity did little to alter HRV in women with PCOS, but it may influence the spontaneous BRS.

Resumo Fundamento: As mulheres com síndrome do ovário policístico (SOP) apresentam alta prevalência de obesidade e alterações no controle autonômico cardiovascular, principalmente modificações na modulação autonômica da variabilidade da frequência cardíaca (VFC). No entanto, existem poucos estudos sobre outros parâmetros de controle autonômico, como a variabilidade da pressão arterial (VPA) e a sensibilidade barorreflexa (SBR). Além disso, ainda há dúvidas sobre a real contribuição da obesidade na alteração do controle autonômico dessas mulheres. Objetivo: Investigar as alterações da modulação autonômica da VPA e SBR em mulheres com SOP, bem como avaliar se essas alterações se devem à SOP ou ao aumento da gordura corporal. Métodos: Foram estudadas 30 voluntárias com peso normal [índice de massa corporal (IMC) < 25 kg/m2] sem SOP (grupo controle) e 60 voluntárias com SOP, divididas em: mulheres com peso normal (IMC < 25 kg/m2, N = 30) e mulheres obesas (IMC > 30 kg/m2, N = 30). Todas as voluntárias foram submetidas à avaliação antropométrica, com registro de parâmetros hemodinâmicos e cardiorrespiratórios em repouso e durante exercício físico, e análise da VFC, VPA e SBR espontânea. As diferenças de p < 5% (p < 0,05) foram consideradas estatisticamente significantes. Resultados: Em relação aos grupos com peso normal, não houve diferenças nos parâmetros autonômicos avaliados. A comparação entre os grupos SOP mostrou que ambos os grupos não diferiram na análise da VPA. No entanto, o grupo SOP obeso apresentou menores valores de SBR espontânea e VFC nas oscilações de baixa e alta frequências, em unidades absolutas. Conclusão: Nossos resultados sugerem que a obesidade pouco influenciou a VFC em mulheres com SOP, mas pode afetar a SBR espontânea.

Women with Polycystic Ovarian Syndrome Exhibit Reduced Baroreflex Sensitivity That May Be Associated with Increased Body Fat.

BACKGROUND: Polycystic ovarian syndrome (PCOS) women have a high prevalence of obesity and alterations in cardiovascular autonomic control, mainly modifications in heart rate variability (HRV) autonomic modulation. However, there are few studies about other autonomic control parameters, such as blood pressure variability (BPV) and baroreflex sensitivity (BRS). In addition, there are still doubts about the obesity real contribution in altering autonomic control in these women. OBJECTIVE: To investigate BPV and BRS autonomic modulation alterations in PCOS women, as well as, to evaluate whether these alterations are due PCOS or increased body fat. METHODS: We studied 30 eutrophic volunteers [body mass index (BMI) < 25 kg/m2] without PCOS (control group) and 60 volunteers with PCOS divided into: eutrophic (BMI < 25 kg/m2, N = 30) and obese women (BMI > 30 kg/m2, N = 30). All volunteers were submitted to anthropometric evaluation, hemodynamic and cardiorespiratory parameters record at rest and during physical exercise, analysis of HRV, BPV and spontaneous BRS. The differences in p less than 5% (p < 0.05) were considered statistically significant. RESULTS: Related to eutrophics groups, there were no differences in autonomic parameters evaluated. The comparison between the PCOS groups showed that both PCOS groups did not differ in the BPV analysis. Although, the obese PCOS group presented lower values of spontaneous BRS and HRV, in low frequency and high frequency oscillations in absolute units. CONCLUSION: Our results suggest that obesity did little to alter HRV in women with PCOS, but it may influence the spontaneous BRS.

Avaliação da força muscular inspiratória (PImáx) durante o desmame da ventilação mecânica em pacientes neurológicos internados na unidade de terapia intensiva / Evaluation of inspiratory muscular force (Plmax) during weaning from mechanical ventilation in neurological patients in the intensive care unit

A ventilação mecânica, freqüentemente necessária em pacientes em estado crítico, pode ser associada à perda de força muscular respiratória por diversos mecanismos. Nosso objetivo foi avaliar a progressão da força da musculatura respiratória durante o processo de desmame, por mensuração seriada da PImáx até a independência completa da ventilação mecânica em pacientes neurológicos. A PImáx foi avaliada evolutivamente, uma vez ao dia, durante todo o período de desmame, com auxílio de manovacuômetro e válvula unidirecional. Foram incluídos no estudo 31 pacientes neurológicos (pós acidente vascular ou trauma crânio-encefálico) em desmame ventilatório e os valores obtidos foram comparados aos previstos, segundo Black e Hyatt15. A média de PImáx inicial (primeiro dia do desmame) foi - 40,0±20,0 cmH2O (39% do previsto) (p < 0, 05); 50% no 5º e 60% no 10º dia de desmame. Houve um aumento de 21% (p < 0,05) do 1º ao 10º dia. Todos os pacientes foram completamente retirados da ventilação mecânica até o 13º dia de desmame. Sendo assim, a evolução ascendente da força muscular inspiratória, em pacientes em ventilação mecânica prolongada, demonstra que a independência completa do ventilador, em pacientes neurológicos, é possível a partir de 72% dos valores previstos.

Mechanical ventilation, often needed in critically ill patients, may be associated to loss of respiratory muscular force due to several mechanisms. The objective was to assess the progression of respiratory muscular force during weaning from mechanical ventilation by using serial measurement of maximum inspiratory pressure until complete discontinuation in neurological patients. The PImax was progressively assessed by using manovacuometer and unidirectional valve once a day during the whole period of mechanical ventilation weaning. Thirty-one neurological patients (after stroke or craniocerebral trauma) undergoing weaning from mechanical ventilation were included for study, and the values obtained were compared to those established by Black and Hyatt15. The initial mean PImax (first day of weaning) was - 40.0±20.0 cmH2O (39% of the expected value) (p < 0.05), reaching 50% at day 5 and 60% at day 10. It was observed an increase of 21% (p < 0.05) between the first and tenth days. On the 13th day, mechanical ventilation had been completely discontinued in all patients. Therefore a progressive evaluation of the inspiratory muscular force in patients undergoing prolonged mechanical ventilation shows that the complete discontinuation is possible in neurological patients with 72% of the established values.

Physical exercise attenuates the cardiac autonomic deficit induced by nitric oxide synthesis blockade.

BACKGROUND: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity. OBJECTIVE: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period. METHODS: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability. RESULTS: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band. CONCLUSION: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

O exercício físico atenua o déficit autonômico cardíaco induzido pelo bloqueio da síntese do óxido nítrico / El ejercicio físico atenúa el déficit autonómico cardiaco inducido por el bloqueo de la síntesis de óxido nítrico / Physical exercise attenuates the cardiac autonomic deficit induced by nitric oxide synthesis blockade

FUNDAMENTO: O bloqueio da síntese do óxido nítrico (NO) é caracterizado pelo aumento da atividade simpática cardíaca, e o treinamento físico promove a redução da atividade simpática. OBJETIVO: Investigamos o efeito do bloqueio da síntese do NO sobre o controle autonômico cardiovascular em ratos submetidos ao exercício aeróbio durante dez semanas. MÉTODOS: Ratos wistar foram divididos em quatro grupos: controle tratados com ração e água ad libitum durante dez semanas (RC); controle tratados com N G-nitro-L-arginine methyl ester (L-NAME) na última semana (RCL); treinados durante dez semanas em esteira motorizada (RT); treinados por dez semanas e tratados com L-NAME na última semana (RTL). O controle autonômico cardiovascular foi investigado em todos os grupos com a utilização de duplo bloqueio com metilatropina e propranolol, e análise da variabilidade. RESULTADOS: Os grupos RCL e RTL apresentaram hipertensão. O grupo RCL apresentou taquicardia e predomínio do tônus simpático na determinação da FC após o bloqueio autonômico farmacológico. O grupo RT apresentou bradicardia e menor freqüência cardíaca (FC) intrínseca em relação aos demais. A avaliação da variabilidade da FC mostrou menores valores absolutos e normalizados na banda de baixa freqüência (BF) no grupo RCL. Por sua vez, o grupo RTL apresentou elevação na banda de BF em valores absolutos. A análise da variabilidade da PAS mostrou que os grupos RCL e RTL apresentaram maiores valores na banda de BF. CONCLUSÃO: O exercício físico prévio impediu o déficit no controle autonômico cardíaco induzido pelo tratamento com L-NAME, no entanto não impediu o aumento na variabilidade da PAS.

BACKGROUND: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity. OBJECTIVE: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period. METHODS: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability. RESULTS: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band. CONCLUSION: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

FUNDAMENTO: El bloqueo de la síntesis de óxido nítrico (NO) se caracteriza por el incremento de la actividad simpática cardiaca, y el entrenamiento físico promueve la reducción de la actividad simpática. OBJETIVO: Investigamos el efecto del bloqueo de la síntesis del NO sobre el control autonómico cardiovascular en ratones sometidos al ejercicio aerobio durante diez semanas. MÉTODOS: Se dividieron ratones wistar en cuatro grupos: control tratados con ración y agua ad libitum durante diez semanas (RC); control tratados con NG-nitro-L-arginina metil éster (L-NAME) en la última semana (RCL); entrenados durante diez semanas en cinta motorizada (RT); entrenados por diez semanas y tratados con L-NAME en la última semana (RTL). Se investigó el control autonómico cardiovascular en todos los grupos con la utilización de doble bloqueo con metilatropina y propranolol, y análisis de la variabilidad. RESULTADOS: Los grupos RCL y RTL presentaron hipertensión. El grupo RCL presentó taquicardia y predominio del tono simpático en la determinación de la FC tras el bloqueo autonómico farmacológico. El grupo RT presentó bradicardia y menor frecuencia cardiaca (FC) intrínseca en relación a los demás. La evaluación de la variabilidad de la FC mostró menores valores absolutos y normalizados en la banda de baja frecuencia (BF) en el grupo RCL. El grupo RTL presentó elevación en la banda de BF en valores absolutos. El análisis de la variabilidad de la PAS mostró que los grupos RCL y RTL presentaron mayores valores en la banda de BF. CONCLUSIÓN: El ejercicio físico previo impidió el déficit en el control autonómico cardiaco inducido por el tratamiento con L-NAME, pero no impidió el aumento en la variabilidad de la PAS.

Nitric oxide synthesis blockade increases hypertrophy and cardiac fibrosis in rats submitted to aerobic training.

OBJECTIVE: The objective of the present study was to evaluate cardiac tissue adaptations in rats submitted to aerobic training after nitric oxide (NO) synthesis blockade. METHODS: The animals (n=48) were divided into four groups: sedentary (CONTROL group); hypertensive after administration of NG-nitro-L-arginine methyl ester for 7 days (L-NAME Group); trained for 8 weeks through swimming exercises (TRAINED Group);trained and treated with L-NAME during the last week (L-NAME TRAINED Group). All the animals were submitted to the experiment procedures for blood pressure (BP) readings and cardiac morphometric evaluation. RESULTS: In comparison to the other groups, the L-NAME and L-NAME TRAINED groups were hypertensive (p<0.05); however, BP elevation in the L-NAME TRAINED group was significantly lower than the L-NAME group (p<0.05). The heart weight indexes for the TRAINED and L-NAME TRAINED groups were higher than the CONTROL and L-NAME groups (p<0.05). Also they had presented higher rates of macroscopic cardiac area and cardiac fibrosis in relation to the rest (p<0.05); comparisons revealed that the values for the L-NAME TRAINED group were significantly higher (p<0.05) than the others. CONCLUSION: Short term NO synthesis blockade in sedentary animals induced hypertension but did not cause cardiac hypertrophy. In the trained animals, the inhibition of NO synthesis attenuated hypertension, induced cardiac hypertrophy and significantly increased myocardial fibrosis, indicating that NO plays an important role in cardiac tissue adaptations caused by aerobic exercise.

O bloqueio da síntese do óxido nítrico promove aumento da hipertrofia e da fibrose cardíaca em ratos submetidos a treinamento aeróbio / Nitric oxide synthesis blockade increases hypertrophy and cardiac fibrosis in rats submitted to aerobic training

OBJETIVO: O presente estudo avaliou as adaptações teciduais cardíacas em ratos submetidos a treinamento aeróbio, após o bloqueio da síntese de óxido nítrico (NO). MÉTODOS: Os animais (n = 48) foram divididos em quatro grupos: sedentários (grupo CONTROLE), hipertensos após administração de Ng-nitro-L-arginina metil éster durante sete dias (grupo L-NAME), treinados por meio de natação durante oito semanas (grupo TREINADO) e treinados e tratados com L-NAME na última semana (grupo TREINADO L-NAME). Em todos os animais foi registrada a pressão arterial (PA) e realizada a avaliação morfométrica cardíaca. RESULTADOS: Os grupos L-NAME e TREINADO L-NAME apresentaram-se hipertensos em relação aos demais (p < 0,05), porém a elevação da PA no grupo TREINADO L-NAME foi significativamente menor em relação ao L-NAME (p < 0,05). Os grupos TREINADO e TREINADO L-NAME apresentaram índice de peso cardíaco maior que os grupos CONTROLE e L-NAME (p < 0,05). Também apresentaram maiores índices de área cardíaca macroscópica e de fibrose cardíaca em relação aos demais (p < 0,05) e, quando comparados, o grupo TREINADO L-NAME mostrou-se significativamente superior (p < 0,05). CONCLUSÃO: O bloqueio a curto prazo da síntese de NO, em animais sedentários, induziu hipertensão, sem no entanto causar hipertrofia cardíaca. Nos animais treinados, a inibição da síntese de NO atenuou a hipertensão e promoveu hipertrofia cardíaca com aumento expressivo da fibrose miocárdica, sugerindo importante papel do NO nas adaptações teciduais cardíacas induzidas pelo treinamento físico aeróbio.

OBJECTIVE: The objective of the present study was to evaluate cardiac tissue adaptations in rats submitted to aerobic training after nitric oxide (NO) synthesis blockade. METHODS: The animals (n=48) were divided into four groups: sedentary (CONTROL group); hypertensive after administration of NG-nitro-L-arginine methyl ester for 7 days (L-NAME Group); trained for 8 weeks through swimming exercises (TRAINED Group);trained and treated with L-NAME during the last week (L-NAME TRAINED Group). All the animals were submitted to the experiment procedures for blood pressure (BP) readings and cardiac morphometric evaluation. RESULTS: In comparison to the other groups, the L-NAME and L-NAME TRAINED groups were hypertensive (p<0.05); however, BP elevation in the L-NAME TRAINED group was significantly lower than the L-NAME group (p<0.05). The heart weight indexes for the TRAINED and L-NAME TRAINED groups were higher than the CONTROL and L-NAME groups (p<0.05). Also they had presented higher rates of macroscopic cardiac area and cardiac fibrosis in relation to the rest (p<0.05); comparisons revealed that the values for the L-NAME TRAINED group were significantly higher (p<0.05) than the others. CONCLUSION: Short term NO synthesis blockade in sedentary animals induced hypertension but did not cause cardiac hypertrophy. In the trained animals, the inhibition of NO synthesis attenuated hypertension, induced cardiac hypertrophy and significantly increased myocardial fibrosis, indicating that NO plays an important role in cardiac tissue adaptations caused by aerobic exercise.