title: Myocardium expression of connexin 43, SERCA2a, and myosin heavy chain isoforms are preserved in nitrofen-induced congenital diaphragmatic hernia rat model.
abstract: BACKGROUND
  Previous morphological studies had produced controversial results with regard to heart development in congenital diaphragmatic hernia (CDH), whereas a few publications investigated cardiac function and myocardial maturation. Myocardium maturation is associated with age-dependent increasing of gene expression of gap junction protein connexin 43 (Cx43), adenosine triphosphatase of the sarcoplasmic reticulum (SERCA2a), as well as switching of myosin heavy chains (MHCs) from beta to alpha isoforms. Our aim was to evaluate myocardium maturity in nitrofen-induced CDH rat model.
  
  
  METHODS
  Fetuses from dated pregnant Sprague-Dawley rats were assigned to 3 experimental groups: control, nitrofen (exposed to nitrofen, without CDH), and CDH (exposed to nitrofen, with CDH). Myocardial samples collected from left ventricle free wall were processed to (i) quantification of messenger RNA (mRNA) of Cx43, SERCA2a, alpha and beta MHC isoforms, as well as beta-actin (housekeeping gene); and (ii) separation of MHC isoforms (alpha and beta isoforms) by sodium dodecyl sulfate polyacrylamide gel electrophoresis silver stained.
  
  
  RESULTS
  We demonstrated that there is no difference in myocardial gene expression of Cx43 (control, 1.0 +/- 0.1; nitrofen, 1.1 +/- 0.2; CDH, 1.3 +/- 0.2) and SERCA2a (control, 1.0 +/- 0.1; nitrofen, 0.9 +/- 0.1; CDH, 1.0 +/- 0.2). Myocardial gene expressions of alpha and beta mRNA of MHC isoforms were slightly decreased both in nitrofen and CDH fetuses when compared with control fetuses, but evaluation of the alpha-to-beta ratios of MHC isoforms at protein level revealed no significant differences between CDH and control (control, 16.9 +/- 2.5; CDH, 17.0 +/- 2.0).
  
  
  CONCLUSIONS
  Myocardial quantification of Cx43 and SERCA2a mRNA, as well as the expression pattern of MHC isoforms at protein levels, was similar in all studied groups. We predict, therefore, that acute heart failure commonly observed in CDH infants might be attributed predominantly to cardiac overload secondary to severe pulmonary hypertension rather than to myocardial immaturity.
authors.affiliation: Life and Health Sciences, Research Institute (ICVS), School of Health Sciences, University of Minho, 4709-057 Braga, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Baptista
authors.forename: Mónica
authors.initials: M
authors.lastname: Recamán
authors.forename: Gustavo
authors.initials: G
authors.lastname: Melo-Rocha
authors.forename: Cristina
authors.initials: C
authors.lastname: Nogueira-Silva
authors.forename: José-Mário
authors.initials: JM
authors.lastname: Roriz
authors.forename: João
authors.initials: J
authors.lastname: Soares-Fernandes
authors.forename: Silvia
authors.initials: S
authors.lastname: Gonzaga
authors.forename: Marta
authors.initials: M
authors.lastname: Santos
authors.forename: Adelino
authors.initials: A
authors.lastname: Leite-Moreira
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Areias
authors.forename: Jorge
authors.initials: J
authors.lastname: Correia-Pinto
mesh_terms: D000818:Animals; D000252:Calcium-Transporting ATPases / Q000032:analysis*; D018031:Connexin 43 / Q000032:analysis*; D004195:Disease Models, Animal; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects; D006548:Hernia, Diaphragmatic / Q000139:chemically induced; D065630:Hernias, Diaphragmatic, Congenital; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000032:analysis*; D010575:Pesticides / Q000494:pharmacology; D010647:Phenyl Ethers / Q000494:pharmacology; D011247:Pregnancy; D020033:Protein Isoforms / Q000032:analysis; D051381:Rats; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases
chemical_list: D018031:Connexin 43; D010575:Pesticides; D010647:Phenyl Ethers; D020033:Protein Isoforms; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D018995:Myosin Heavy Chains; D000252:Calcium-Transporting ATPases; C007350:nitrofen