Physical Training Improves Cardiac Structure and Function of Rats After Doxorubicin-Induced Cardiomyopathy

Abstract Background: The use of doxorubicin in chemotherapy has been associated with cardiotoxicity and heart failure. Physical exercise produces favorable morphofunctional adaptations in the cardiovascular system and may reverse cardiac dysfunction in patients undergoing chemotherapy. Objective: To assess the effects of physical training on myocardial structure, cardiac function, and exercise tolerance in Wistar rats initiated after the onset of cardiotoxicity-induced cardiotoxicity. Methods: This study investigated 30 adult male Wistar rats randomly divided into four groups: control (C), exercise (EX), doxorubicin (DX), and doxorubicin and exercise (DXEX). The DX and DXEX groups received six doses of doxorubincin from 1.25 mg/kg body weight up to a cumulative dose of 7.5 mg/kg. Injections were administered intraperitoneally three times a week for two weeks; after this stage, the EX and DXEX groups started physical training (swimming) sessions three times a week with a load of 5% of their body weight. Echocardiography and exercise tolerance tests were performed. Generalized linear models were used in statistical analysis, and a p<0.05 was set as statistically significant. Results: Left ventricular shortening fraction and ejection fraction were reduced in the DX group compared to C, EX, and DXEX. The DXEX group showed greater tolerance to effort when compared to the DX and C groups. Conclusion: Physical training, initiated after the onset of doxorubicin-induced cardiotoxicity, improved cardiac function and exercise tolerance in rats.

Action of leucine in heart hypertrophy induced by thyroid hormone in rats / Ação da leucina na hipertrofia cardíaca induzida pelo hormônio tireoidiano em ratos

Leucine is a regulator of protein metabolism in vivo, but there is little information regarding its effect on hyperthyroidism-induced cardiac hypertrophy. This study aimed to verify the action of leucine in heart hypertrophy using an experimental model of hyperthyroidism in rats. A total of 40 Wistar rats were used and allocated randomly into four groups: control (C), hormone (H), leucine (L) and hormone plus leucine (HL). Hyperthyroidism was induced by administering daily by gavage 20 µg of levothyroxine sodium in aqueous suspension per 100 g of body weight, and leucine was supplemented by adding 5% of the amino acid to conventional food. After 28 days, the heart was removed and weighed; the left ventricle was separated along with the interventricular septum and weighed. Histological slides were made from the left ventricle and stained with hematoxylin-eosin to measure the transverse diameter of cardiomyocytes. Two-way analysis of variance (ANOVA) and Tukey post-test were used and significance level set at 5%. There was a significant increase in the absolute heart weight, the left ventricular weight and cardiomyocyte diameter in rats of the H group compared to the other groups. The addition of leucine inhibited heart hypertrophy. Levothyroxine sodium-induced cardiac hypertrophy in Wistar rats is inhibited by leucine.

A leucina é um regulador do metabolismo proteico in vivo, e existem poucas informações referentes à sua ação na hipertrofia cardíaca induzida pelo hipertireoidismo. O estudo teve por objetivo verificar a ação da leucina na hipertrofia cardíaca de ratos Wistar em um modelo experimental de hipertireoidismo. Foram utilizados 40 animais, alocados ao acaso em quatro grupos, sendo: grupo controle (C), grupo hormônio (H), grupo leucina (L) e grupo hormônio + leucina (HL). O hipertireoidismo foi induzido administrando-se, diariamente, 20µg/100 gramas de levotiroxina sódica em suspensão aquosa, por gavagem e a leucina foi suplementada adicionando-se 5% do aminoácido à ração convencional. Ao final do período experimental, o coração foi removido e pesado. Foi separado o ventrículo esquerdo juntamente com o septo interventricular e pesado. Foram feitas lâminas histológicas a partir do ventrículo esquerdo, coradas com hematoxilina-eosina, para a medida do diâmetro transversal dos cardiomiócitos. Foi utilizada a análise de variância (ANOVA) de duas vias e pós-teste de Tukey e adotado um P<0,05. Houve aumento significante para o peso do coração, peso do ventrículo esquerdo e diâmetro dos cardiomiócitos no grupo H em relação aos demais grupos. A adição de leucina inibe a hipertrofia. A hipertrofia cardíaca induzida em ratos Wistar pela levotiroxina sódica é inibida pela leucina.

The thyroid hormone receptor β-selective agonist GC-1 does not affect tolerance to exercise in hypothyroid rats

Objective Investigate the effect of GC-1 on tolerance to exercise in rats with experimental hypothyroidism. Materials and methods Hypothyroidism was induced with methimazole sodium and perchlorate treatment. Six groups with eight animals were studied: control group (C), hypothyroid group without treatment (HYPO); hypothyroidism treated with physiological doses of tetraiodothyronine (T4) or 10 times higher (10×T4); hypothyroidism treated with equal molar doses of GC-1 (GC-1) or 10 times higher (10×GC-1). After eight weeks, each animal underwent an exercise tolerance test by measuring the time (seconds), in which the rats were swimming with a load attached to their tails without being submerging for more than 10 sec. After the test, the animals were killed, and blood samples were collected for biochemical analysis, and the heart and soleus muscle were removed for weighing and morphometric analysis of the cardiomyocyte. Results Hypothyroidism significantly reduced tolerance to exercise and, treatment with GC-1 1× or T4 in physiological doses recover tolerance test to normal parameters. However, high doses of T4 also decreased tolerance to physical exercise. Conversely, ten times higher doses of GC-1 did not impair tolerance to exercise. Interestingly, hypothyroidism, treated or not with T4 in a physiological range, GC-1 or even high doses of GC-1 (10X) did not change cardiomyocyte diameters and relative weight of the soleus muscle. In contrast, higher doses of T4 significantly increased cardiomyocyte diameter and induced atrophy of the soleus muscle. Conclusion Unlike T4, GC-1 in high doses did not modify tolerance to physical exercise in the rats with hypothyroidism. .

Resposta Hipertrofica da Associacao de Hormonio Tireoidiano e de Exercicio Fisico no Coracao de Ratos / Hypertrophic response of the Association of Thyroid Hormone and Exercise in the Heart of Rats

Fundamento: A hipertrofia cardíaca constitui um dos componentes do remodelamento cardíaco e ocorre em resposta a aumento da atividade ou da sobrecarga funcional do coração. Objetivo: Avaliar a resposta hipertrófica da associação do hormônio tireoidiano e do exercício físico no coração de ratos. Método: Foram utilizados 37 ratos da linhagem Wistar, machos, adultos, distribuídos aleatoriamente em quatro grupos: controle, hormônio (HT), exercício (E), hormônio tireoidiano e exercício (H + E). O grupo hormônio recebeu diariamente levotiroxina sódica por gavagem, na dose de 20 μg de hormônio tireoidiano/100 g de peso corporal; o grupo exercício realizou natação cinco vezes por semana, com peso adicional correspondente a 20% do peso corporal, durante seis semanas; no grupo H + E foram aplicados simultaneamente os tratamentos dos grupos HT e E. A estatísica utilizada foi a análise de variância complementada, quando necessário, pelo teste de Tukey e o teste de correlação de Pearson. Resultados: O T4 foi mais elevado nos grupos HT e H + E. O peso total do coração foi maior nos grupos que receberam hormônio tireoidiano, e o peso ventricular esquerdo foi maior no grupo HT. O diâmetro transversal dos cardiomiócitos aumentou nos grupos HT, E e H + E. A porcentagem de colágeno foi maior nos grupos E e H + E. A análise da correlação entre as variáveis apresentou distintas respostas. Conclusão: A associação do hormônio tireoidiano com exercício físico de elevada intensidade produziu hipertrofia cardíaca e gerou um padrão hipertrófico não correlacionado diretamente ao grau de fibrose. .

Background: Cardiac hypertrophy is a component of cardiac remodeling occurring in response to an increase of the activity or functional overload of the heart. Objective: Assess hypertrophic response of the association of thyroid hormone and exercise in the rat heart. Methods: We used 37 Wistar rats, male, adults were randomly divided into four groups: control, hormone (TH), exercise (E), thyroid hormone and exercise (H + E); the group received daily hormone levothyroxine sodium by gavage at a dose of 20 μg thyroid hormone/100g body weight, the exercise group took swimming five times a week, with additional weight corresponding to 20% of body weight for six weeks; in group H + E were applied simultaneously TH treatment groups and E. The statistics used was analysis of variance, where appropriate, by Tukey test and Pearson correlation test. Results: The T4 was greater in groups TH and H + E. The total weight of the heart was greater in patients who received thyroid hormone and left ventricular weight was greater in the TH group. The transverse diameter of cardiomyocytes increased in groups TH, E and H + E. The percentage of collagen was greater in groups E and H + E Correlation analysis between variables showed distinct responses. Conclusion: The association of thyroid hormone with high-intensity exercise produced cardiac hypertrophy, and generated a standard hypertrophy not directly correlated to the degree of fibrosis. .

Agentes Comunitários de Saúde, formação e perfil profissional: o caso de Duque de Caxias, RJ / Community Health Workers, training and professional profile: the case of Duque de Caxias, RJ

Este estudo teve como objetivo analisar o perfil de trabalho e descrever a formação profissional dos Agentes Comunitários de Saúde (ACS) no Município de Duque de Caxias. Trata-se de um estudo descritivo e de abordagem quantitativa e qualitativa, com base em uma perspectiva de triangulação de métodos. A pesquisa foi dividida em dois momentos distintos durante a coleta de dados. No primeiro, reuniram-se informações que configurassem todo o histórico de implementação do trabalho dos ACS, desde o surgimento das primeiras equipes. No segundo momento, aplicou-se um questionário aos 51 ACS que compõem o quadro funcional, sendo 23 de unidades da Estratégia Saúde da Família (ESF) e 28 da Equipe de Agentes Comunitários de Saúde (EACS). Foram também realizadas entrevistas individuais com oito participantes. Na análise dos dados, foi possível: a) construir a trajetória histórica dos ACS no Município, incluindo seu perfil sociodemográfico; b) mapear e descrever o perfil e condições de trabalho, a formação dos ACS, o interesse e as motivações quanto à profissão, as atividades de educação em saúde realizadas e o vínculo do ACS com o enfermeiro. O campo de pesquisa foi o município de Duque de Caxias, situado na Baixada Fluminense, no Estado do Rio de Janeiro. Os resultados mostram que a maioria dos participantes é do sexo feminino (94,1%), se encontrava na faixa etária entre 40-49 anos (43%), possui o segundo grau completo (72,5%); por outro lado, apenas 29,4% participam de alguma associação ou sindicato que represente a categoria, 84,3%, atuam em média há mais de sete anos, 84,3 % consideram o seu serviço gerador de estresse, 62,7% não tiveram acesso a algum curso/capacitação antes de serem inseridos na prática. Entre os motivos para atuar como um ACS, citam-se: ajudar a comunidade, estar perto dos filhos e trabalhar perto de casa; já entre as desvantagens do trabalho estão condições precárias de trabalho e baixo salário/vinculo trabalhista precário...

This study aimed to analyze the job profile and describe the training of Community Health Agents (CHA) in Duque de Caxias. This is a descriptive study with a quantitative and qualitative approach, based on a perspective of triangulation methods. The research was divided into two distinct periods during the data collection. At first we gathered information that would configure the entire history of implementing the work of the CHA, since the emergence of the first teams. In the second phase, a questionnaire was applied to 51 CHA that make up the workforce, with 23 units of the Family Health Strategy (FHS) and 28 of the Staff of Community Health Workers (SCHW). Individual interviews were also conducted with eight participants. In analyzing the data, it was possible: a) build the historical trajectory of CHA in the City, including their sociodemographic profiles; b) to map and describe the profile and working conditions, the training of CHA, interest and motivations regarding the profession, education activities in health in the CHA and the bond with the nurse. The research field was the municipality of Duque de Caxias, located in the Baixada Fluminense, in the State of Rio de Janeiro. The results show that the majority of participants were female (94.1%) were in the age group between 40-49 years (43%), has a high school degree (72.5%), and secondly, only 29.4% participate in any association or union representing the category, 84.3 % work for an average of more than seven years, 84.3% consider their generator service stress, 62.7% had no access to any courses/training before being inserted into practice. Among the reasons to act as an CHA, we mention: helping the community, being close to the kids and work close to home, already among the disadvantages of work are poor working conditions and low pay/precarious labor bond...

Efeito da leucina na hipertrofia cardíaca e na concentração sérica de creatina quinase em ratos Wistar em hipertireoidismo experimental / Effect of leucine in cardiac hypertrophy and serum creatine kinase in rats in experimental hyperthyroidism

A leucina é um regulador do metabolismo proteico in vivo, e existem poucas informações referentes à sua ação na hipertrofia cardíaca induzida pelo hipertireoidismo experimental e sua relação com a creatina quinase sérica. O estudo teve por objetivo verificar a ação da leucina na hipertrofia cardíaca e na concentração sérica de creatina quinase em ratos Wistar em hipertireoidismo. Foram utilizados 20 animais, divididos em quatro grupos sendo estes o controle, hormônio, leucina e hormônio + leucina. O hipertireoidismo foi induzido administrando-se, diariamente, 20µg/100 gramas de levotiroxina sódica em suspensão aquosa, por gavagem. A leucina foi suplementada adicionando-se 5% do aminoácido à ração convencional. O sangue foi coletado por punção cardíaca e as análises feitas em kits para CK-NAC, CK-MB e TSH. Ao final do período experimental de sete dias o coração foi removido e pesado. Posteriormente, foi separado o ventrículo esquerdo juntamente com o septo interventricular e pesado. Na comparação estatística foi utilizada a análise de variância (ANOVA) de duas vias e pós-teste de Tukey, considerando-se significativos valores de p<0,05. As concentrações séricas de CK-MB sérica foram menores no grupo leucina (p<0,05) e hormônio + leucina (p<0,05) em comparação a controle. O grupo hormônio, apresentou peso relativo do coração maior que o grupo controle (p<0,05) e peso absoluto do coração maior que hormônio + leucina (p<0,05). Em conclusão, a leucina parece reduzir a hipertrofia cardíaca e a concentração sérica da creatina quinase por mecanismos ainda desconhecidos.

Leucine is a regulator of protein metabolism in vivo, and there is little information regarding its action on cardiac hypertrophy induced by experimental hyperthyroidism and its relationship to serum creatine kinase. The study aimed to verify the effect of leucine in cardiac hypertrophy and serum creatine kinase in rats with hyperthyroidism. We used 20 animals were divided into four groups and these control, hormone, hormone + leucine and leucine. Hyperthyroidism was induced by administration of daily 20µg/100 grams of levothyroxine sodium in aqueous suspension by gavage. Leucine was supplemented by adding 5% of the amino conventional diet. Blood was collected by cardiac puncture and analyzes made in kit CK-NAC, CK-MB and TSH. At the end of the trial period of seven days the hearts were removed and weighed. Subsequently, the left ventricle was separated together with the interventricular septum and weighed. In statistical comparison was used analysis of variance (ANOVA) and two-way post-Tukey test, considering p values <0.05. Serum concentrations of serum CK-MB were lower in leucine (p <0.05) and hormone + leucine (p <0.05) compared to control. The hormone group, showed greater relative heart weight than the control group (p <0.05) and absolute heart weight greater than hormone + leucine (p <0.05). In conclusion, leucine appears to reduce cardiac hypertrophy and serum concentration of creatine kinase by unknown mechanisms.