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Doctoral Thesis
DOI
Document
Author
Full name
Rebeca Rodrigues Lopes Roslindo Figueira
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2018
Supervisor
Committee
Sbragia Neto, Lourenço (President)
Ortolan, Erika Veruska Paiva
Fabro, Alexandre Todorovic
Manso, Paulo Henrique
Tannuri, Ana Cristina Aoun
Title in Portuguese
Avaliação morfológica e funcional da musculatura cardíaca de neonatos de coelhos com hérnia diafragmática congênita criada cirurgicamente
Keywords in Portuguese
cTnI
Ecocardiografia
Hernia diafragmática congênita
Sobrecarga cardíaca
Abstract in Portuguese
A hérnia diafragmática congênita (CDH) tem incidência de aproximadamente 1:2500 nascidos vivos e mortalidade de aproximadamente 70%. A hipertensão arteiral pulmonar é umas das principais complicações neonatais e pode levar à sobrecarga cardíaca. A principal estratégia de tratamento para os casos de grave hipoplasia pulmonar no período pré-natal é a traqueo-oclusão fetal (TO), no entanto, as consequências geradas ao tecido cardíaco são incertas, tanto na CDH quanto no tratamento com TO. Troponininas (cTnI e cTnT) são proteínas intracelulares miocárdicas utilizadas como indicativo de lesão cardiomiocítica. Portanto, nosso objetivo foi avaliar as alterações anatômicas, funcionais e bioquímicas dos ventrículos esquerdo (VE) e direito (VD) na CDH e CDHTO por meio das análises de ecocardiografia (ECO), histologia e bioquímica no modelo experimental de CDH. Para isso, foram utilizados neonatos de coelhos (n=10) divididos em três grupos: controle (C), hérnia diafragmática congênita (CDH), e hérnia diafragmática congênita + traqueo-oclusão (CDHTO). A cirurgia de CDH foi realizada no dia 25 da gestação (DG) da coelha (termo = 31 dias), e a TO no 27DG. A coleta foi realizada em 30DG, a ECO neonatal foi realizada imediatamente após retirada do útero e após o sacrifício os pulmões e coração foram coletados. A mortalidade da CDH fi de 20% e de CDHTO de 30%. Os resultados da ECO e da histologia mostraram hipoplasia de VE nos grupos CDH e CDHTO (*p<0,05), sendo que no VD, o grupo CDH apresentou dilatação e o grupo CDHTO apresentou hipoplasia. Na imunofluorescência (IF), western blotting (WB) e RT-qPCR houve aumento de cTnI no VD dos grupos CDH e CDHTO em relação à C (*p<0,05), sem alteração de expressão de cTnI no VE (NS); cTnT não apresentou alteração em ambos ventrículos (NS). Concluímos que as alterações cardíacas em CDH e CDHTO podem ser verificadas logo após o nascimento e há associação das alterações ecocardiográficas, histométricas e bioquímicas, como a hipoplasia de VE e dilatação de VD associada ao aumento tecidual de cTnI no VD no grupo CDH, indicando sofrimento cardíaco ainda no período fetal. Além disso, a realização do tratamento fetal pela TO no grupo CDH (CDHTO) não apresentou melhora das alterações do comprometimento do miocárdio.
Title in English
Morphological and functional evaluation of the cardiac muscle in newborn rabbits with congenital diaphragmatic hernia surgically created
Keywords in English
Cardiac overload
Congenital diaphragmatic hernia
cTnI
Echocardiography
Abstract in English
Congenital diaphragmatic hernia (CDH) has an incidence of approximately 1: 2500 live births and a mortality rate of approximately 70%. Pulmonary hypertension is one of the major neonatal complications and can lead to cardiac overload. The main treatment strategy for cases of severe prenatal pulmonary hypoplasia is fetal tracheal occlusion (TO), however, the consequences in the cardiac tissue are uncertain, in both the CDH and the TO treatment. cTnI and cTnT are myocardial intracellular proteins used as an indicative of cardiomyocyte injury that could be measured in neonates with CDH. Therefore, our aim was to evaluate the anatomical, functional and biochemical alterations in the left ventricle (LV) and in the right ventricle (RV) of neonates with CDH and CDHTO through echocardiography (ECO), histology and biochemistry analysis in the experimental rabbit CDH model. Neonates of rabbits (n = 10) were divided into three groups: C (control), CDH (congenital diaphragmatic hernia) and CDHTO (congenital diaphragmatic hernia + tracheal occlusion). CDH surgery was performed on day 25 of gestation (GD) of the rabbit (term = 31 days), and TO treatment on 27GD. The harvest was performed in 30GD, followed by neonatal ECO immediately after birth, then after sacrifice the lungs and heart were harvested. The mortality in the surgical groups was 20% CDH and 30% CDHTO. The ECO and histology results showed LV hypoplasia in the CDH and CDHTO (* p <0.05) groups. In the RV, the CDH group presented dilation and the CDHTO group presented hypoplasia. In the immunofluorescence (IF), western blotting (WB) and RTqPCR analysis there was an increase of cTnI in the RV of CDH and CDHTO groups in comparison with C group (* p<0.05), with no alteration of cTnI expression in the LV (NS). There was no difference of cTnT expression in both ventricles (NS). We conclude that cardiac alterations in CDH and CDHTO can be verified soon after birth, also there is an association of echocardiographic, histometric and biochemical alterations, such as LV hypoplasia and RV dilation with increased cTnI tissue expression in the RV of CDH group, indicating cardiac distress still in the fetal period. In addition, the performance of CDH fetal treatment by TO, (CDHTO) group, did not improve the myocardial detriment.
 
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Publishing Date
2019-07-01
 
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