Efeitos da restrição de sono em modelo animal de lesão cerebral isquêmica
Arquivos
Data
2015-08-27
Autores
Kim, Lenise Jihe 
Orientadores
Andersen, Monica Levy
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Introdução: O fluxo sanguíneo cerebral é um importante fator associado com o prognóstico de pacientes após um desfecho cerebrovascular. Uma condição de hipoperfusão cerebral compromete diversas estruturas do sistema nervoso central, especialmente o hipocampo. Restrição de sono reduz o fluxo sanguíneo cerebral em regiões relacionadas à regulação de processos cognitivos, sugerindo um possível efeito limitante da falta de sono no prognóstico de doenças cerebrovasculares. Objetivos: Investigar o efeito da restrição de sono na taxa de mortalidade, função neurológica, memória de curto e longo-prazo e citoarquitetura da região CA1 do hipocampo de animais submetidos à hipoperfusão cerebral global e permanente, um modelo de redução do fluxo sanguíneo cerebral. Métodos: Sessenta ratos Wistar machos e adultos foram distribuídos em 4 grupos experimentais, conforme os protocolos de oclusão das artérias carótida comum (CCAO) e de restrição de sono (SR): nSR+nCCAO, SR+nCCAO, nSR+CCAO, e SR+CCAO. Os grupos SR+nCCAO e SR+CCAO foram submetidos ao protocolo de restrição de sono por 20 horas/dia durante 10 dias. A hipoperfusão cerebral foi induzida pela oclusão permanente das artérias carótida comum. A função neurológica e a memória de curto e longo-prazo foram avaliadas pela escala de Bederson e pelo teste de reconhecimento de objetos, respectivamente. A análise de alterações neuropatológicas da região CA1 do hipocampo foi realizada após 14 dias de hipoperfusão cerebral. Resultados: A taxa de mortalidade foi de 40% nos grupos nSR+CCAO e SR+CCAO. No entanto, a restrição de sono reduziu significativamente o tempo de sobrevida dos animais submetidos à hipoperfusão cerebral. Após 7 e 14 dias de hipoperfusão cerebral, 11% e 33% dos animais nSR+CCAO e SR+CCAO apresentaram disfunção neurológica grave, respectivamente. Uma associação significativa entre uma maior frequência de comprometimentos de memória com o xvi grupo SR+CCAO foi observada. As alterações neuropatológicas na região CA1 do hipocampo foram similares entre os grupos. Conclusões: Restrição de sono potencializa os efeitos negativos no tempo de sobrevida, função neurológica e na memória de curto e longo-prazo em condições de hipoperfusão cerebral.
Introduction: Cerebral blood flow is an important factor associated with the prognosis of patients after a cerebrovascular event. A condition of cerebral hypoperfusion impairs several structures of the central nervous system, especially the hippocampus. Sleep restriction reduces the cerebral blood flow in important regions related to the regulation of cognitive processes, suggesting a possible limiting effect of sleep loss on the prognosis of cerebrovascular diseases. Objectives: To investigate the effect of sleep restriction on the mortality rate, neurological function, short- and long-term memory, and cytoarchitecture of CA1 region of hippocampus of animals submitted to global and permanent cerebral hypoperfusion, a model of cerebral blood flow reduction. Methods: Sixty adult male Wistar rats were distributed in 4 experimental groups, according to the protocol of common carotid artery occlusion (CCAO) and sleep restriction (SR): nSR+nCCAO, SR+nCCAO, nSR+CCAO, and SR+CCAO. The groups SR+nCCAO and SR+CCAO were submitted to 20 hours/day of sleep restriction during 10 days. The cerebral hypoperfusion was induced by the permanent common carotid artery occlusion. The neurological function and the short- and long-term memory were evaluated by the Bederson scale and the novel object recognition test, respectively. The analysis of neuropathological alterations in CA1 region of hippocampus was performed after 14 days of cerebral hypoperfusion. Results: The mortality rate was 40% in the nSR+CCAO and SR+CCAO groups. However, sleep restriction significantly reduced the survival time of the animals submitted to cerebral hypoperfusion. After 7 and 14 days of cerebral hypoperfusion, 11% and 33% of the nSR+CCAO and SR+CCAO animals showed severe neurological dysfunction, respectively. A significant association between a high frequency of memory impairments with the group SR+CCAO was observed. The neuropathological alterations in CA1 region of hippocampus were similar among the groups. Conclusions: Sleep restriction potentiates the negative effects on the survival time, neurological function and short- and long-term memories of cerebral hypoperfusion conditions.
Introduction: Cerebral blood flow is an important factor associated with the prognosis of patients after a cerebrovascular event. A condition of cerebral hypoperfusion impairs several structures of the central nervous system, especially the hippocampus. Sleep restriction reduces the cerebral blood flow in important regions related to the regulation of cognitive processes, suggesting a possible limiting effect of sleep loss on the prognosis of cerebrovascular diseases. Objectives: To investigate the effect of sleep restriction on the mortality rate, neurological function, short- and long-term memory, and cytoarchitecture of CA1 region of hippocampus of animals submitted to global and permanent cerebral hypoperfusion, a model of cerebral blood flow reduction. Methods: Sixty adult male Wistar rats were distributed in 4 experimental groups, according to the protocol of common carotid artery occlusion (CCAO) and sleep restriction (SR): nSR+nCCAO, SR+nCCAO, nSR+CCAO, and SR+CCAO. The groups SR+nCCAO and SR+CCAO were submitted to 20 hours/day of sleep restriction during 10 days. The cerebral hypoperfusion was induced by the permanent common carotid artery occlusion. The neurological function and the short- and long-term memory were evaluated by the Bederson scale and the novel object recognition test, respectively. The analysis of neuropathological alterations in CA1 region of hippocampus was performed after 14 days of cerebral hypoperfusion. Results: The mortality rate was 40% in the nSR+CCAO and SR+CCAO groups. However, sleep restriction significantly reduced the survival time of the animals submitted to cerebral hypoperfusion. After 7 and 14 days of cerebral hypoperfusion, 11% and 33% of the nSR+CCAO and SR+CCAO animals showed severe neurological dysfunction, respectively. A significant association between a high frequency of memory impairments with the group SR+CCAO was observed. The neuropathological alterations in CA1 region of hippocampus were similar among the groups. Conclusions: Sleep restriction potentiates the negative effects on the survival time, neurological function and short- and long-term memories of cerebral hypoperfusion conditions.
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Citação
KIM, Lenise Jihe. Efeitos da restrição de sono em modelo animal de lesão cerebral isquêmica. 2015. 212 f. Dissertação (Mestrado em Psicobiologia) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, 2015.