Vias de sinalização mucosa-muscular na dismotilidade esofagiana induzida pelo ácido ursodesoxicólico: estudo experimental com cobaias
Data
2015-08-27
Autores
Souza, Rodrigo Caetano de 
Orientadores
Fernandes, Fernando Augusto Mardiros Herbella
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Introdução: Alterações motoras do esôfago são frequentemente encontradas em pacientes com doença do refluxo gastroesofágico. Isto pode ser causado por refluxo ácido ou biliar. Em um estudo experimental anterior, a exposição do esôfago ao ácido ursodeoxicólico, um componente da bile, diminuiu a amplitude das contrações esofágicas, mas não quando a mucosa esofágica foi ressecada. Estes resultados indicaram que a ação bile na motilidade esofágica é relacionada à sinalização da mucosa para a camada muscular e não um processo transmural. Este trabalho tem o objetivo de tentar identificar a natureza exata do caminho da sinalização mucosa-muscular por bloqueio de receptores através de estudo experimental. Material e Método: Quinze esôfagos de cobaias foram isolados, e sua contratilidade avaliada com transdutores de força. Fragmentos de três centímetros foram obtidos a partir do esófago distal e montados em câmaras de perfusão de órgãos isolados, contendo solução de Krebs-Henseleit oxigenado por uma mistura de 95% de O2 e 5% CO2 (pH 7,4). Os fragmentos foram ligados a transdutores de força ligados a um microprocessador para permitir a variação da tensão basal. As amostras foram mantidas, após a montagem, com uma tensão basal de 1 g durante 1 hora para estabilização. A medida da força (amplitude de contração) foi registrada. O esófagos foram incubados em 100 μM/L de ácido ursodesoxicólico durante 1 hora e 5 contrações sequenciais induzidas por 40 μM de KCl espaçadas por cinco minutos foram medidos. Após 30 minutos, as amostras de esófagos foram incubadas em 3 diferentes antagonistas da contração do músculo liso: atropina (1 μM) em 5, suramina (1 μM) em 5 e genisteína (1 μM) em 5. O mesmo protocolo para contrações foi repetido. Os valores são expressos como média ± desvio padrão e abrangem a média de cinco estímulos. Os procedimentos experimentais foram aprovados pelo Conselho de Revisão Institucional da Universidade. Resultados: Amplitudes de contração após incubação com a bile, mas antes da incubação com os antagonistas foram de 1,5 ± 0,8 g; 1,2 ± 0,8 g e 1,2 ± 0,5 g para atropina, suramina e genisteína, respectivamente. A média das amplitudes de contração após instilação dos antagonistas foi de 1,6 ± 0,8 g, 1,4 ± 0,5 g, 0,9 ± 0,5 g, respectivamente. Não houve diferença na amplitude de contração antes e após a instilação de atropina (p = 0,2), suramina (p = 0,5) ou genisteína (p = 0,1). Conclusões: Nossos resultados mostram que o bloqueio das vias colinérgica (atropina), purinérgica (suramina) ou da tirosina quinase (genisteína) não alteram a dismotilidade esofágica induzida pela bile. Outro caminho molecular pode desempenhar o papel neste cenário.
Introduction: Esophageal motor abnormalities are frequently found in patients with gastroesophageal reflux disease. This may be caused by acid or bile reflux. In a previous experimental study, esophageal exposure to ursodeoxycholic acid, a component of bile, decreased esophageal contraction amplitudes but not when the esophageal mucosa was resected. These findings indicated that bile action in esophageal motility is directed towards mucosal signaling to the muscular layer and not a trans mural process. This study aims to try to identify the exact nature of the mucosa-muscular signaling path by receptors blockage in an experimental study. Materials & Methods: Fifteen guinea pig esophagi were isolated, and its contractility assessed with force transducers. Three-centimeter fragments were obtained from the distal esophagus and were mounted in the chambers for isolated organ perfusion containing Krebs-Henseleit solution oxygenated by a mixture of 95% O2 and 5% CO2 (pH 7.4). The fragments were connected to force transducers attached to a micromanipulator to allow variation of basal tension. The specimens were kept after assembly with a basal tension of 1 g for 1 hour to stabilization. Developed force (contraction amplitude) was recorded. The esophagi were incubated in 100 μML ursodeoxycholic acid for 1 hour and 5 sequential contractions induced by 40 μM KCl spaced by 5 minutes were measured. After 30 minutes, esophagi specimens were incubated in 3 different smooth-muscle contraction antagonist: atropine (1 μM) in 5, suramin (1 μM) in 5 and genistein (1 μM) in 5. The same protocol for contractions was repeated. Values are expressed as mean ± standard deviation and encompass the mean of five stimuli. Experimental procedures were approved by the University Institutional Review Board. Results: Contraction amplitudes after bile incubation but before antagonists incubation were 1.5±0.8 g, 1.2±0.8 g, and 1.2±0.5 g for atropine, suramin and genistein, respectively. Mean contraction amplitudes after antagonists instillation were 1.6±0.8 g, 1.4±0.5 g, 0.9±0.5 g, respectively. There was no different in contraction amplitude before and after instillation of atropine (p=0.2), suramin (p=0.5) or genistein (p=0.1). Conclusion: Our results show that blockage of cholinergic (atropine), purinergic (suramin) or tyrosine kinase (genistein) paths do not change esophageal dysmotility induced by bile. Other molecular path may play the role in this scenario.
Introduction: Esophageal motor abnormalities are frequently found in patients with gastroesophageal reflux disease. This may be caused by acid or bile reflux. In a previous experimental study, esophageal exposure to ursodeoxycholic acid, a component of bile, decreased esophageal contraction amplitudes but not when the esophageal mucosa was resected. These findings indicated that bile action in esophageal motility is directed towards mucosal signaling to the muscular layer and not a trans mural process. This study aims to try to identify the exact nature of the mucosa-muscular signaling path by receptors blockage in an experimental study. Materials & Methods: Fifteen guinea pig esophagi were isolated, and its contractility assessed with force transducers. Three-centimeter fragments were obtained from the distal esophagus and were mounted in the chambers for isolated organ perfusion containing Krebs-Henseleit solution oxygenated by a mixture of 95% O2 and 5% CO2 (pH 7.4). The fragments were connected to force transducers attached to a micromanipulator to allow variation of basal tension. The specimens were kept after assembly with a basal tension of 1 g for 1 hour to stabilization. Developed force (contraction amplitude) was recorded. The esophagi were incubated in 100 μML ursodeoxycholic acid for 1 hour and 5 sequential contractions induced by 40 μM KCl spaced by 5 minutes were measured. After 30 minutes, esophagi specimens were incubated in 3 different smooth-muscle contraction antagonist: atropine (1 μM) in 5, suramin (1 μM) in 5 and genistein (1 μM) in 5. The same protocol for contractions was repeated. Values are expressed as mean ± standard deviation and encompass the mean of five stimuli. Experimental procedures were approved by the University Institutional Review Board. Results: Contraction amplitudes after bile incubation but before antagonists incubation were 1.5±0.8 g, 1.2±0.8 g, and 1.2±0.5 g for atropine, suramin and genistein, respectively. Mean contraction amplitudes after antagonists instillation were 1.6±0.8 g, 1.4±0.5 g, 0.9±0.5 g, respectively. There was no different in contraction amplitude before and after instillation of atropine (p=0.2), suramin (p=0.5) or genistein (p=0.1). Conclusion: Our results show that blockage of cholinergic (atropine), purinergic (suramin) or tyrosine kinase (genistein) paths do not change esophageal dysmotility induced by bile. Other molecular path may play the role in this scenario.
Descrição
Citação
SOUZA, Rodrigo Caetano de. Vias de sinalização mucosa-muscular na dismotilidade esofagiana induzida pelo ácido ursodesoxicólico: estudo experimental com cobaias. 2015. 60 f. Dissertação (Mestrado em Ciência Cirúrgica Interdisciplinar) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, 2015.