Estudo da termorregulação em ratos espontaneamente hipertensos submetidos aos exercícios físicos progressivo e contínuo até a fadiga em ambiente quente
Arquivos
Data
2013-03-22
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Viçosa
Resumo
A hipótese do presente estudo foi de que durante o exercício progressivo até a fadiga (EPF) e o exercício contínuo até a fadiga (ECF) em ambiente quente (AQ) os ratos espontaneamente hipertensos (SHR) apresentariam déficits termorregulatórios em relação aos seus controles normotensos. Assim, o objetivo do estudo foi estudar a termorregulação em ratos espontaneamente hipertensos (SHR) submetidos aos EPF e ECF em AQ. Para isto foram medidas a temperatura corporal interna (Tint), a temperatura da pele da cauda (Tpele), o consumo de oxigênio (VO2) e o tempo total de exercício até a fadiga (TTE) em ratos Wistar (n=8) e SHR (n=8), durante quatro condições experimentais: (1) exercício progressivo até a fadiga em ambiente quente (EPF-AQ), (2) exercício progressivo até a fadiga em ambiente temperado (EPF-AT), (3) exercício contínuo até a fadiga em ambiente quente (ECF-AQ) e (4) exercício contínuo até a fadiga em ambiente temperado (ECF-AT). A temperatura da esteira para o ambiente temperado (AT) e o AQ foi fixada em 25 e 32°C, respectivamente. O teste de Kolmogorov-Smirnov foi utilizado para testar a normalidade dos dados. As diferenças entre os grupos foram analisadas utilizando ANOVA two-way, seguido do post-hoc de Tukey, quando necessário. Para avaliar os valores de Tint, Tpele e VO2 durante os experimentos em relação ao momento basal e de fadiga, foi utilizado o teste t de Student. Os dados são apresentados como média ± EPM. O nível de significância adotado foi de até 5%. No EPF, o grupo SHR-AT apresentou maior VO2 em relação ao grupo WIS-AT, em contrapartida o grupo SHR-AT também apresentou maior Tpele em relação ao grupo WIS-AT. Desta forma, ocorreu um equilíbrio térmico que acarretou em Tint semelhante entre os grupos no EPF. No ECF, o grupo SHR-AQ apresentou maior Tint em relação ao grupo WIS-AQ. Além disto, não houve diferenças na Tpele e no VO2 entre os grupos. Quando o exercício foi realizado em AQ o TTE foi reduzido em relação ao AT. A EM foi menor nos SHR em comparação aos WIS, tanto no AT quanto no AQ. Foi demonstrado que durante o EPF- AT os SHRs apresentaram maior produção e dissipação de calor nos momentos finais do exercício em relação aos seus controles, desta forma a Tint foi semelhante entre SHR e WIS. Durante o ECF-AQ os animais SHRs apresentaram um balanço térmico alterado, com Tint mais elevada que os seus controles 8 no momento final do exercício, apesar de apresentarem dissipação e produção de calor semelhante aos seus controles.
The hypothesis of this study was that during progressive exercise until fatigue (PEF) and continuous exercise until fatigue (CEF) in a hot enviroment (HE) the spontaneously hypertensive rats (SHR) would present thermoregulatory déficits in relation to theirs normotensives controls. The objective was to study thermoregulation in SHR submitted to the PEF and CEF in HE. For that were measured the core body temperature (Tcore), the tail skin temperature (Tskin), the oxigen cosumption (VO2) and time to fatigue (TTE) in Wistar rats (n=8) and SHR (n=8) for four experimental conditions: (1) progressive exercise until fatigue in a hot enviroment (PEF-HE), (2) progressive exercise until fatigue in a temperate enviroment (PEF-HE), (3) continuous exercise until fatigue in a hot enviroment (CEF-HE) and (4) continuous exercise until fatigue in a temperate enviroment (CEF-HE). The temperature of the treadmill to the temperate enviroment (TE) e HE was fixed at 25 and 32°C, respectively. The Kolmogorov-Sminorf was used to test the normality of the data. Differences between groups were analyzed using two-way ANOVA followed by Tukey post-hoc, if necessary. To evaluate the values of Tcore, Tskin and VO2 during the experiments at baseline and fatigue, we used the Student t test. Data are presented as mean ± SEM, The level of significance adopted was until 5%. In PEF, the SHR-TE had higher VO2 than group WIS-TE, however the SHR-TE also showed higher Tskin than in group WIS-TE. Thus, there was a thermal equilibrium wich resulted in Tcore similar between groups in PEF. In the CEF, the SHR-HE showed higher Tcore compared to WIS-HE group. Moreover, there were no differences in Tskin and VO2 between groups. When the exercise was conducted in the HE the TTE was reduced compared to TE. It was shown that during the EPF-AT SHR had higher production and heat dissipation in the final moments of the year in relation to the controls, so the Tint was similar between SHR and WIS. During the ECF-AQ animals Tcore SHR had higher than their controls at the very end of the year, despite having dissipation and heat production similar to their controls.
The hypothesis of this study was that during progressive exercise until fatigue (PEF) and continuous exercise until fatigue (CEF) in a hot enviroment (HE) the spontaneously hypertensive rats (SHR) would present thermoregulatory déficits in relation to theirs normotensives controls. The objective was to study thermoregulation in SHR submitted to the PEF and CEF in HE. For that were measured the core body temperature (Tcore), the tail skin temperature (Tskin), the oxigen cosumption (VO2) and time to fatigue (TTE) in Wistar rats (n=8) and SHR (n=8) for four experimental conditions: (1) progressive exercise until fatigue in a hot enviroment (PEF-HE), (2) progressive exercise until fatigue in a temperate enviroment (PEF-HE), (3) continuous exercise until fatigue in a hot enviroment (CEF-HE) and (4) continuous exercise until fatigue in a temperate enviroment (CEF-HE). The temperature of the treadmill to the temperate enviroment (TE) e HE was fixed at 25 and 32°C, respectively. The Kolmogorov-Sminorf was used to test the normality of the data. Differences between groups were analyzed using two-way ANOVA followed by Tukey post-hoc, if necessary. To evaluate the values of Tcore, Tskin and VO2 during the experiments at baseline and fatigue, we used the Student t test. Data are presented as mean ± SEM, The level of significance adopted was until 5%. In PEF, the SHR-TE had higher VO2 than group WIS-TE, however the SHR-TE also showed higher Tskin than in group WIS-TE. Thus, there was a thermal equilibrium wich resulted in Tcore similar between groups in PEF. In the CEF, the SHR-HE showed higher Tcore compared to WIS-HE group. Moreover, there were no differences in Tskin and VO2 between groups. When the exercise was conducted in the HE the TTE was reduced compared to TE. It was shown that during the EPF-AT SHR had higher production and heat dissipation in the final moments of the year in relation to the controls, so the Tint was similar between SHR and WIS. During the ECF-AQ animals Tcore SHR had higher than their controls at the very end of the year, despite having dissipation and heat production similar to their controls.
Descrição
Palavras-chave
Termorregulação, Ratos, Hipertensão, Thermoregulation, Mouse, Hypertension
Citação
CAMPOS, Helton Oliveira. Study of thermoregulation in spontaneously hypertensive rats subjected to continuous and progressive exercise to fatigue in a hot enviroment. 2013. 83 f. Dissertação (Mestrado em Aspectos sócio-culturais do movimento humano; Aspectos biodinâmicos do movimento humano) - Universidade Federal de Viçosa, Viçosa, 2013.