Remodelação miocárdica pós-lesão cardíaca induzida por videocirurgia, em tilápias-do-nilo
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Data
2018-02-05
Autores
Crivelaro, Roberta Martins [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As doenças cardiovasculares constituem grande problema de saúde pública. A necessidade do entendimento do processo de remodelação cardíaca tem acarretado em aumento do número de pesquisas envolvendo terapias biológicas. Neste contexto, peixes teleósteos emergem como opção de modelo experimental, pois possuem homologia morfofuncional e imunológica com mamíferos. Tilápias-do-Nilo (Oreochromis niloticus) já vêm sendo empregadas no estudo de diversas doenças que afetam seres humanos. Com a presente pesquisa, objetivou-se desenvolver técnica de acesso videocirúrgico e induzir lesão cardíaca mecânica, em tilápias-do-Nilo; avaliar a eficácia da metadona no controle da dor associada à lesão; e caracterizar os mecanismos de remodelação do miocárdio ventricular, empregando-se avaliações por eletrocardiograma e por microscopias. As avaliações foram conduzidas antes, 1 h depois, e transcorridos 7, 14, 30, 60 e 90 dias da lesão cardíaca. O acesso à cavidade celomática foi realizado utilizando-se um punch de biopsia de 3 mm, permitindo a introdução de endoscópio para posterior amputação do ápice do coração. O procedimento foi executado rapidamente e com baixo índice de mortalidade transoperatória (5,60%) e pós-operatória (3,38%). Aproximadamente 6% de tecido cardíaco, apresentando epicárdio e miocárdio, foi removido com a pinça de biopsia, sendo que a videocirurgia permitiu boa visibilização interna, padronização do tamanho da lesão e alta precisão. A avaliação da analgesia fornecida pela metadona foi realizada por meio de parâmetros fisiológicos e comportamentais. Os resultados demonstraram que, na dose empregada, a metadona não possuiu efeito analgésico em tilápias-do-Nilo, contudo, o tempo de recuperação da anestesia foi maior entre os animais que receberam metadona, sugerindo um possível efeito sedativo do fármaco. Os ventrículos da tilápia-do-Nilo, após lesão, não apresentaram evidências de regeneração e evoluíram para um processo de remodelamento caracterizado pelos espessamentos das paredes do ventrículo e do epicárdio, pela hipertrofia dos cardiomióticos, e por alterações em atividade elétrica. Mudanças no estado ordenado de agregação do colágeno intersticial, no tamanho e no formato dos núcleos dos cardiomiócitos, e na supraorganização da cromatina nuclear dos cardiomiócitos, bem como presença de células poliplóides, de células necróticas e de células apoptóticas foram observadas. Em conclusão, a tilápia-do-Nilo parece ser um bom organismo modelo para estudos em cardiologia experimental, uma vez que seu ventrículo, após amputação do ápice do coração, acumula muitas das alterações vistas em corações de pacientes humanos cardiopatas. Vantagens adicionais referentes ao emprego de tilápias-do-Nilo em pesquisas incluem o tamanho dos animais, o que possibilita a utilização de técnicas menos onerosas; e a facilidade de alojamento e de manutenção de um grande número de indivíduos num espaço reduzido, com baixa taxa de mortalidade.
Cardiovascular disease are a public health big problem. The need for understanding cardiac repair mechanism has increased the number of researches biologic therapy field. In this context, teleost fish show as a experimental model, as they have morpho-functional and immunologic homology whit mammals. Nile tilapia (Oreochromis niloticus) has been used to study several diseases that affect humans. The present study aimed to develop a video surgery access and mechanically induce cardiac injury in Nile tilapia; to evaluate the analgesic activity of methadone in effectively control the pain associated with the injury; and characterize myocardial repair mechanisms by microscopy and electrocardiogram analysis. Data were recorded before cardiac injury and then 1 hour, 7, 14, 30, 60 and 90 days after cardiac injury. The access to coelomatic cavity was made with a 3-mm biopsy punch, allowing the passage of an endoscope for amputation of the cardiac apex. The procedure was quickly performed with intraoperative (5.6%) and post-operatory (3.38%) low mortality rates. Approximately 6% cardiac tissue, including epicardium and myocardium were removed with the biopsy forceps, once video surgery allowed good visualization, standard lesion areas and great precision. To evaluate the analgesic effect of methadone, physiological and behavioral parameters were recorded. Results show that in the dose used, methadone did not show analgesic effect in Nile tilapia. However, recovery time was longer in fish that received methadone, suggesting a sedative effect of the drug in the specie. The ventricles of Nile tilapia, after lesion, did not showed any evidence of regeneration, progressing for a remodeling process, characterized by a thicker ventricle wall and epicardium, by cardiomiocytes hypertrophy, and changes in electrical activity. Changes in the interstitial collagen aggregation state, size and shape of cardiomiocytes nuclei, and in the supra-organization of nuclear chromatin of cardiomiocytes, as well as presence of ploydy, necrotic and apoptotic cells, were also oberved It was concluded that Nile tilapia seems to be a good experimental model organism for experimental cardiology studies, once its ventricle, after have its apex amputated, shows many of the alterations observed in hearts of humans cardiac patients. Additional advantages regarding the use of Nile tilapia in research include the size of the animals, that allows the use of cheaper techniques; and the practical way to keep a great number of animals in small spaces, with low mortality rates.
Cardiovascular disease are a public health big problem. The need for understanding cardiac repair mechanism has increased the number of researches biologic therapy field. In this context, teleost fish show as a experimental model, as they have morpho-functional and immunologic homology whit mammals. Nile tilapia (Oreochromis niloticus) has been used to study several diseases that affect humans. The present study aimed to develop a video surgery access and mechanically induce cardiac injury in Nile tilapia; to evaluate the analgesic activity of methadone in effectively control the pain associated with the injury; and characterize myocardial repair mechanisms by microscopy and electrocardiogram analysis. Data were recorded before cardiac injury and then 1 hour, 7, 14, 30, 60 and 90 days after cardiac injury. The access to coelomatic cavity was made with a 3-mm biopsy punch, allowing the passage of an endoscope for amputation of the cardiac apex. The procedure was quickly performed with intraoperative (5.6%) and post-operatory (3.38%) low mortality rates. Approximately 6% cardiac tissue, including epicardium and myocardium were removed with the biopsy forceps, once video surgery allowed good visualization, standard lesion areas and great precision. To evaluate the analgesic effect of methadone, physiological and behavioral parameters were recorded. Results show that in the dose used, methadone did not show analgesic effect in Nile tilapia. However, recovery time was longer in fish that received methadone, suggesting a sedative effect of the drug in the specie. The ventricles of Nile tilapia, after lesion, did not showed any evidence of regeneration, progressing for a remodeling process, characterized by a thicker ventricle wall and epicardium, by cardiomiocytes hypertrophy, and changes in electrical activity. Changes in the interstitial collagen aggregation state, size and shape of cardiomiocytes nuclei, and in the supra-organization of nuclear chromatin of cardiomiocytes, as well as presence of ploydy, necrotic and apoptotic cells, were also oberved It was concluded that Nile tilapia seems to be a good experimental model organism for experimental cardiology studies, once its ventricle, after have its apex amputated, shows many of the alterations observed in hearts of humans cardiac patients. Additional advantages regarding the use of Nile tilapia in research include the size of the animals, that allows the use of cheaper techniques; and the practical way to keep a great number of animals in small spaces, with low mortality rates.
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Palavras-chave
cardiopatias, coração, regeneração, teleósteos, ventrículo, endoscopia, cardiopathies, heart, regeneration, teleost, ventricle, endoscopy