Role of resistance training in bone macro and micro damages in an estrogen absence animal model.

AIMS: We evaluated the effects of resistance training (RT) on bone properties, morphology, and bone extracellular matrix (ECM) remodeling markers in an ovariectomy (OVX) rat model. MAIN METHODS: Thirty-six female rats were divided into four groups: sham sedentary, OVX sedentary, sham RT, and OVX RT. Rats performed RT for ten weeks, during which they climbed a ladder with progressive loads attached to the tail. Tibias were stored for dual-energy X-ray densitometry (DXA), micro-computed tomography (micro-CT), and biomechanical, biophysical, and biochemical analysis. Femurs were stored for morphological, gene expression, and gelatin zymography analysis. KEY FINDINGS: OVX decreased bone mineral density, stiffness, maximal load, and calcium content, which was reversed by RT. The trabecular number, connectivity, and MMP-13 gene expression decreased in OVX groups. Furthermore, OVX increased run-related transcription factor-2 (RUNX-2) and osteoprotegerin (OPG) gene expression, and increased the number of adipocytes in bone marrow and MMP-2 activity. SIGNIFICANCE: RT was efficient in preventing or reversing changes in bone biomechanical properties in OVX groups, improving fracture load and resilience, which is relevant to prevent fractures. On the other hand, RT did not decrease the number of bone adipocytes in the OVX-RT group. However, RT was efficient for increasing trabecular thickness and cortical bone volume, which improved bone resistance. Our findings provide further insights into the mechanisms involved in the role of RT in OVX damage protection.

Moderate intensity swimming training on bone mineral density preservation under food restriction in female rats

Abstract Aim: To investigate the effect of moderate-intensity swimming training on bone mineral density under a 20% food restriction (FR) schedule for 12 weeks in female rats. Methods: Forty female Wistar rats were distributed into four groups: control (CG), exercised (EG), food restriction (FRG), and food restriction/exercised (FREG). At 95 days. the animals were subjected to aquatic adaptation and then performed the critical load test to individually determine the critical load intensity (CLi, % of body mass). Exercised groups swam 5 days a week, 30 minutes daily with weekly adjustment of the load equivalent to 80% of the CLi. The FR schedule was 20% in relation to CG and started concomitantly with physical training (PT). After 12 weeks, visceral fat weight was recorded and the femur was collected for biophysical and biomechanical analysis. Results: FR and exercise training promoted visceral fat reduction (p<0.01). FR reduced bone mineral density (p<0.01), while exercise training prevented such reduction. On the other hand, FR and exercise training did not promote significant changes in biomechanical parameters of the femur. Conclusion: Exercise training at moderate intensity was efficient in preserving bone mineral density despite long term of FR at 20%.

Endothelial Dysfunction and Inflammation Precedes Elevations in Blood Pressure Induced by a High-Fat Diet.

BACKGROUND: Obesity leads to a chronic inflammatory state, endothelial dysfunction and hypertension. OBJECTIVE: To establish the time-course of events regarding inflammatory markers, endothelial dysfunction, systolic blood pressure (SBP) in obesity in only one experimental model. METHODS: We fed male Wistar rats (eight-week age) with a standard diet (Control - CT, n = 35), or palatable high-fat diet (HFD, n = 35) for 24 weeks. Every six weeks, 7 animals from each group were randomly selected for euthanasia. SBP and serum levels of interleukin-6, tumor necrosis factor-α, C-reactive protein, adiponectin and nitric oxide were determined. Endothelial and vascular smooth muscle functions were determined in dissected aorta and lipid peroxidation was measured. Statistical significance was set at p < 0.05. RESULTS: Levels of pro-inflammatory cytokines began to increase after six weeks of a high-fat diet, while those of the anti-inflammatory cytokine adiponectin decreased. Interestingly, the endothelial function and serum nitric oxide began to decrease after six weeks in HFD group. The SBP and lipid peroxidation began to increase at 12 weeks in HFD group. In addition, we showed that total visceral fat mass was negatively correlated with endothelial function and positively correlated with SBP. CONCLUSION: Our results show the time-course of deleterious effects and their correlation with obesity.

Endothelial Dysfunction and Inflammation Precedes Elevations in Blood Pressure Induced by a High-Fat Diet / Disfunção Endotelial e Inflamação Precedem a Elevação da Pressão Arterial Induzida por Dieta Hiperlipídica

Abstract Background: Obesity leads to a chronic inflammatory state, endothelial dysfunction and hypertension. Objective: To establish the time-course of events regarding inflammatory markers, endothelial dysfunction, systolic blood pressure (SBP) in obesity in only one experimental model. Methods: We fed male Wistar rats (eight-week age) with a standard diet (Control - CT, n = 35), or palatable high-fat diet (HFD, n = 35) for 24 weeks. Every six weeks, 7 animals from each group were randomly selected for euthanasia. SBP and serum levels of interleukin-6, tumor necrosis factor-α, C-reactive protein, adiponectin and nitric oxide were determined. Endothelial and vascular smooth muscle functions were determined in dissected aorta and lipid peroxidation was measured. Statistical significance was set at p < 0.05. Results: Levels of pro-inflammatory cytokines began to increase after six weeks of a high-fat diet, while those of the anti-inflammatory cytokine adiponectin decreased. Interestingly, the endothelial function and serum nitric oxide began to decrease after six weeks in HFD group. The SBP and lipid peroxidation began to increase at 12 weeks in HFD group. In addition, we showed that total visceral fat mass was negatively correlated with endothelial function and positively correlated with SBP. Conclusion: Our results show the time-course of deleterious effects and their correlation with obesity.

Resumo Fundamento: A obesidade leva a um estado de inflamação crônica, disfunção endotelial e hipertensão. Objetivo: Estabelecer a sequência de eventos relacionados a marcadores inflamatórios, disfunção endotelial e pressão arterial sistólica (PAS) na obesidade em um modelo experimental. Métodos: Ratos Wistar machos (8 semanas de idade) receberam dieta padrão (Controle - CT, n = 35) ou uma dieta palatável hiperlipídica (DHL, n = 35) por 24 semanas. A cada seis semanas, 7 animais de cada grupo foram aleatoriamente selecionados para eutanásia. Foram determinados a PAS, e níveis séricos de interleucina-6, fator de necrose tumoral-a, proteína C reativa, adiponectina e óxido nítrico. As funções do músculo liso endotelial e vascular foram determinadas na aorta dissecada, e medida a peroxidação lipídica. A significância estatística foi estabelecida em p < 0,05. Resultados: os níveis das citocinas pró-inflamatórias começaram a aumentar após seis semanas de dieta hiperlipídica, enquanto os níveis da citocina anti-inflamatória adiponectina diminuíram. Um resultado interessante foi a redução da função endotelial e do óxido nítrico após seis semanas no grupo DHL. Além disso, mostramos que a massa de tecido adiposo visceral total esteve negativamente correlacionada com função endotelial e positivamente correlacionada com a PAS. Conclusão: Nossos resultados demonstram a progressão temporal dos efeitos deletérios e sua correlação com a obesidade.

Resveratrol Treatment Normalizes the Endothelial Function and Blood Pressure in Ovariectomized Rats.

BACKGROUND:: Despite knowing that resveratrol has effects on blood vessels, blood pressure and that phytostrogens can also improve the endothelium-dependent relaxation/vasodilation, there are no reports of reveratrol's direct effect on the endothelial function and blood pressure of animals with estrogen deficit (mimicking post-menopausal increased blood pressure). OBJECTIVE:: To verify the effect of two different periods of preventive treatment with resveratrol on blood pressure and endothelial function in ovariectomized young adult rats. METHODS:: 3-month old female Wistar rats were used and distributed in 6 groups: intact groups with 60 or 90 days, ovariectomized groups with 60 or 90 days, and ovariectomized treated with resveratrol (10 mg/kg of body weight per day) for 60 or 90 days. The number of days in each group corresponds to the duration of the experimental period. Vascular reactivity study was performed in abdominal aortic rings, systolic blood pressure was measured and serum nitric oxide (NO) concentration was quantified. RESULTS:: Ovariectomy induced blood pressure increase 60 and 90 days after surgery, whereas the endothelial function decreased only 90 days after surgery, with no difference in NO concentration among the groups. Only longer treatment (90 days) with resveratrol was able to improve the endothelial function and normalize blood pressure. CONCLUSION:: Our results suggest that 90 days of treatment with resveratrol is able to improve the endothelial function and decrease blood pressure in ovariectomized rats. FUNDAMENTOS:: Apesar de se saber que o resveratrol apresenta efeitos sobre a pressão arterial e os vasos sanguíneos, e que os fitoestrógenos podem melhorar o relaxamento/vasodilatação dependente do endotélio, não há relatos do efeito direto do resveratrol sobre a pressão arterial e a função endotelial em animais com deficiência de estrógeno (mimetizando a pressão arterial aumentada pós-menopausa). OBJETIVO:: Verificar o efeito de dois diferentes períodos de tratamento preventivo com resveratrol sobre a pressão arterial e a função endotelial em ratas adultas jovens ovariectomizadas. MÉTODOS:: Foram utilizadas ratas Wistar com 3 meses de idade, distribuídas em 6 grupos: grupos intactas com 60 ou 90 dias, grupos ovariectomizadas com 60 ou 90 dias, grupos ovariectomizadas e tratadas com resveratrol na dose de 10mg/kg de massa corporal por dia, durante 60 ou 90 dias, sendo o número de dias em cada grupo relativo à duração do período experimental. Foi realizado um estudo de reatividade vascular em anéis da aorta abdominal, mensurada a pressão arterial sistólica e quantificada a concentração sérica de óxido nítrico (NO). RESULTADOS:: A ovariectomia induziu aumento da pressão arterial 60 e 90 dias após a cirurgia, enquanto a função endotelial decaiu apenas após 90 dias, e não houve diferença na concentração de NO entre os grupos. Apenas o tratamento prolongado com resveratrol (90 dias) foi capaz de melhorar a função endotelial e normalizar a pressão arterial. CONCLUSÃO:: Nossos resultados sugerem que o tratamento por 90 dias com resveratrol é capaz de melhorar a função endotelial e diminuir a pressão sanguínea em ratas ovariectomizadas.

Resveratrol Treatment Normalizes the Endothelial Function and Blood Pressure in Ovariectomized Rats / Tratamento com Resveratrol Normaliza a Função Endotelial e a Pressão Arterial em Ratas Ovariectomizadas

Abstract Background: Despite knowing that resveratrol has effects on blood vessels, blood pressure and that phytostrogens can also improve the endothelium-dependent relaxation/vasodilation, there are no reports of reveratrol's direct effect on the endothelial function and blood pressure of animals with estrogen deficit (mimicking post-menopausal increased blood pressure). Objective: To verify the effect of two different periods of preventive treatment with resveratrol on blood pressure and endothelial function in ovariectomized young adult rats. Methods: 3-month old female Wistar rats were used and distributed in 6 groups: intact groups with 60 or 90 days, ovariectomized groups with 60 or 90 days, and ovariectomized treated with resveratrol (10 mg/kg of body weight per day) for 60 or 90 days. The number of days in each group corresponds to the duration of the experimental period. Vascular reactivity study was performed in abdominal aortic rings, systolic blood pressure was measured and serum nitric oxide (NO) concentration was quantified. Results: Ovariectomy induced blood pressure increase 60 and 90 days after surgery, whereas the endothelial function decreased only 90 days after surgery, with no difference in NO concentration among the groups. Only longer treatment (90 days) with resveratrol was able to improve the endothelial function and normalize blood pressure. Conclusion: Our results suggest that 90 days of treatment with resveratrol is able to improve the endothelial function and decrease blood pressure in ovariectomized rats.

Resumo Fundamentos: Apesar de se saber que o resveratrol apresenta efeitos sobre a pressão arterial e os vasos sanguíneos, e que os fitoestrógenos podem melhorar o relaxamento/vasodilatação dependente do endotélio, não há relatos do efeito direto do resveratrol sobre a pressão arterial e a função endotelial em animais com deficiência de estrógeno (mimetizando a pressão arterial aumentada pós-menopausa). Objetivo: Verificar o efeito de dois diferentes períodos de tratamento preventivo com resveratrol sobre a pressão arterial e a função endotelial em ratas adultas jovens ovariectomizadas. Métodos: Foram utilizadas ratas Wistar com 3 meses de idade, distribuídas em 6 grupos: grupos intactas com 60 ou 90 dias, grupos ovariectomizadas com 60 ou 90 dias, grupos ovariectomizadas e tratadas com resveratrol na dose de 10mg/kg de massa corporal por dia, durante 60 ou 90 dias, sendo o número de dias em cada grupo relativo à duração do período experimental. Foi realizado um estudo de reatividade vascular em anéis da aorta abdominal, mensurada a pressão arterial sistólica e quantificada a concentração sérica de óxido nítrico (NO). Resultados: A ovariectomia induziu aumento da pressão arterial 60 e 90 dias após a cirurgia, enquanto a função endotelial decaiu apenas após 90 dias, e não houve diferença na concentração de NO entre os grupos. Apenas o tratamento prolongado com resveratrol (90 dias) foi capaz de melhorar a função endotelial e normalizar a pressão arterial. Conclusão: Nossos resultados sugerem que o tratamento por 90 dias com resveratrol é capaz de melhorar a função endotelial e diminuir a pressão sanguínea em ratas ovariectomizadas.