RESUMEN
OBJECTIVE: We developed an in vitro model for vasospasm post subarachnoid hemorrhage that was suitable for investigating brain vessel autoregulation. We further investigated the effects of iodinated contrast medium on the vascular tone and the myogenic response of spastic cerebral vessels. METHOD: We isolated and perfused the superior cerebellar arteries of rats. The vessels were pressurized and studied under isobaric conditions. Coagulated blood was used to simulate subarachnoid hemorrhage. The contrast medium iodixanol was applied intraluminally. RESULTS: Vessels exposed to blood developed significantly stronger myogenic tone (65.7 ± 2.0% vs 77.1 ± 1.2% of the maximum diameter, for the blood and the control group, respectively) and significantly decreased myogenic response, compared with the control groups. The contrast medium did not worsen the myogenic tone or the myogenic response in any group. CONCLUSION: Our results show that deranged myogenic response may contribute to cerebral blood flow disturbances subsequent to subarachnoid hemorrhage. The contrast medium did not have any negative influence on vessel tone or myogenic response in this experimental setting.
Asunto(s)
Encéfalo/irrigación sanguínea , Medios de Contraste/farmacología , Modelos Animales de Enfermedad , Yodo/farmacología , Hemorragia Subaracnoidea/complicaciones , Vasoespasmo Intracraneal/etiología , Animales , Arterias Cerebrales/patología , Masculino , Desarrollo de Músculos/fisiología , Presión , Ratas Sprague-Dawley , Reproducibilidad de los Resultados , Hemorragia Subaracnoidea/patología , Factores de Tiempo , Vasoespasmo Intracraneal/patologíaRESUMEN
Objective We developed an in vitro model for vasospasm post subarachnoid hemorrhage that was suitable for investigating brain vessel autoregulation. We further investigated the effects of iodinated contrast medium on the vascular tone and the myogenic response of spastic cerebral vessels. Method We isolated and perfused the superior cerebellar arteries of rats. The vessels were pressurized and studied under isobaric conditions. Coagulated blood was used to simulate subarachnoid hemorrhage. The contrast medium iodixanol was applied intraluminally. Results Vessels exposed to blood developed significantly stronger myogenic tone (65.7 ± 2.0% vs 77.1 ± 1.2% of the maximum diameter, for the blood and the control group, respectively) and significantly decreased myogenic response, compared with the control groups. The contrast medium did not worsen the myogenic tone or the myogenic response in any group. Conclusion Our results show that deranged myogenic response may contribute to cerebral blood flow disturbances subsequent to subarachnoid hemorrhage. The contrast medium did not have any negative influence on vessel tone or myogenic response in this experimental setting. .
Objetivo Desenvolvemos um modelo in vitro para vasoespasmo subsequente à hemorragia subaracnóide que foi adequado para investigar a autorregularão dos vasos cerebrais. Em seguida investigamos os efeitos o meio de contraste iodado no tônus vascular e na resposta miogênica dos vasos cerebrais espásticos. Método Isolamos e perfundimos as artérias cerebelares superiores de ratos. Os vasos foram pressurizados e estudados em condições isobáricas. Sangue coagulado foi utilizado para simular hemorragia subaracnóide. O meio de contraste iodixanol foi aplicado intraluminarmente. Resultados Os vasos expostos ao sangue desenvolveram aumento significativo do tônus miogênico (65.7 ± 2.0% vs 77.1 ± 1.2% do maior diâmetro, para o grupo de sangue e o grupo controle, respectivamente) com resposta miogênica significativamente menor do que aquela dos controles. O meio de contraste iodado não piorou o tônus miogênico ou a resposta miogênica em nenhum dos grupos. Conclusão Nossos resultados mostram que uma resposta miogênica pode contribuir para as alterações de fluxo sanguíneo cerebral subsequentes à hemorragia subaracnóide. O meio de contraste iodado não teve nenhuma influência negativa no tônus vascular ou na resposta miogênica neste modelo experimental. .