Estudo comparativo da termorregulação durante o repouso e exercício físico em dois modelos experimentais: Wistar versus Wistar Kyoto
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Data
2016-07-13
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Universidade Federal de Viçosa
Resumo
O objetivo geral desta dissertação foi analisar as diferenças no comportamento termorregulatório durante o repouso e exercício físico entre duas linhagens experimentais habitualmente utilizadas na pesquisa científica como controle para o rato espontaneamente hipertenso (SHR): os Wistar (WIS) e os Wistar Kyoto (WKY). No primeiro capítulo, foram analisadas as variáveis de repouso por meio do estudo do ritmo circadiano da temperatura central (T central ) e da atividade locomotora dos animais. Foram realizadas também análises da composição corporal dos animais por meio da avaliação do índice de massa corporal (IMC) e da análise direta do percentual de gordura. Como resultado, foi constatado que os animais apresentam semelhanças no comportamento basal da T central , no entanto o envelhecimento provoca alterações nessas variáveis, no sentido de diminuir a T central e a amplitude desta, o que é mais evidente na linhagem Wistar Kyoto. Com relação à composição corporal, entre os animais jovens (WIS16 vs. WKY16), foi verificado que os WIS apresentaram maior IMC, o que não foi observado entre os animais mais velhos, e, na comparação do percentual de gordura, independentemente da idade, os WIS apresentam maior percentual de gordura em relação aos WKY. Em conclusão, as linhagens estudadas apresentam um comportamento da T central basal semelhante. Entretanto, com o processo de envelhecimento, ocorre uma perda da sincronização entre os ritmos circadianos estudados. No segundo capítulo, foram analisadas as variáveis obtidas a partir do exercício físico, que foi dividido em: exercício progressivo até a fadiga (EPF); exercício constante relativo (ECR); e exercício constante absoluto (ECA). Os dados de T central durante o exercício foram coletados por meio de transmissão do sinal de telemetria e posterior análise pelo software VitalView. Como resultado, foi constatado que os animais da linhagem WKY apresentam desempenho superior durante o exercício aeróbico, no entanto o comportamento da T central e da T pele é semelhante entre as linhagens durante os protocolos de exercício propostos. Com relação ao acumulo de calor, foi comprovado que os animais da linhagem WIS acumulam mais calor do que os WKY, independentemente da massa corporal. Concluindo, as linhagens estudadas apresentam um comportamento termorregulatório semelhante durante o exercício físico aeróbico.
The overall objective of this dissertation was to analyze the differences in thermoregulatory behavior during rest and exercise between two strains commonly used in scientific research as a control for the spontaneously hypertensive rat (SHR), the Wistar (WIS) and Wistar Kyoto (WKY). In the first chapter we analyzed the resting variables through the study of circadian rhythm of core temperature (Tcentral) and the locomotor activity of animals. Were also carried out analysis of body composition of animals by body mass index (BMI) and direct analysis of the percentage of fat. As a result, it was found that the animals exhibit similarities in baseline behavior Tcentral, however, the aging causes changes in these variables in order to decrease the Tcentral, which is more evident in Wistar Kyoto strain. Regarding the body composition among young animals (WIS16 vs. WKY16), it was found that the WIS had higher BMI, which was not observed among older animals. Was compared the percentage of fat, WIS present a higher percentage of fat compared to WKY, regardless of age. In conclusion, the studied strains show a similar Tcentral baseline behavior and the process of aging, there is a loss of synchronization between the circadian rhythms studied. In the second chapter, the variables were analyzed obtained from the exercise, which was divided into progressive exercise until fatigue (EPF), constant exercise of relative (ECR) and absolute constant exercise (ECA). Data of Tcentral during exercise were collected through transmission of telemetry signal and subsequent analysis by VitalView software. As a result, it was found that animals of WKY show better perform during aerobic exercise. However, the behavior of Tcentral and Tskin is similar between the strain during the proposed exercise protocols. Regarding the heat storage, it was found that animals of WIS strain storage more heat than WKY strain independent of body mass. In conclusion, the studied strains have similar thermoregulatory behavior during aerobic exercise. xii
The overall objective of this dissertation was to analyze the differences in thermoregulatory behavior during rest and exercise between two strains commonly used in scientific research as a control for the spontaneously hypertensive rat (SHR), the Wistar (WIS) and Wistar Kyoto (WKY). In the first chapter we analyzed the resting variables through the study of circadian rhythm of core temperature (Tcentral) and the locomotor activity of animals. Were also carried out analysis of body composition of animals by body mass index (BMI) and direct analysis of the percentage of fat. As a result, it was found that the animals exhibit similarities in baseline behavior Tcentral, however, the aging causes changes in these variables in order to decrease the Tcentral, which is more evident in Wistar Kyoto strain. Regarding the body composition among young animals (WIS16 vs. WKY16), it was found that the WIS had higher BMI, which was not observed among older animals. Was compared the percentage of fat, WIS present a higher percentage of fat compared to WKY, regardless of age. In conclusion, the studied strains show a similar Tcentral baseline behavior and the process of aging, there is a loss of synchronization between the circadian rhythms studied. In the second chapter, the variables were analyzed obtained from the exercise, which was divided into progressive exercise until fatigue (EPF), constant exercise of relative (ECR) and absolute constant exercise (ECA). Data of Tcentral during exercise were collected through transmission of telemetry signal and subsequent analysis by VitalView software. As a result, it was found that animals of WKY show better perform during aerobic exercise. However, the behavior of Tcentral and Tskin is similar between the strain during the proposed exercise protocols. Regarding the heat storage, it was found that animals of WIS strain storage more heat than WKY strain independent of body mass. In conclusion, the studied strains have similar thermoregulatory behavior during aerobic exercise. xii
Descrição
Palavras-chave
Temperatura corporal - Regulação, Exercícios físicos, Repouso, Rato como animal de laboratório
Citação
REZENDE, Leonardo Mateus Teixeira. Estudo comparativo da termorregulação durante o repouso e exercício físico em dois modelos experimentais: Wistar versus Wistar Kyoto. 2016. 69 f. Dissertação (Mestrado em Educação Física) - Universidade Federal de Viçosa, Viçosa. 2016.