Mouse models for the study of postnatal cardiac hypertrophy

Abstract

The main objective of this study was to create a postnatal model for cardiac hypertrophy (CH), in order to explain the mechanisms that are present in childhood cardiac hypertrophy. Five days after implantation, intraperitoneal (IP) isoproterenol (ISO) was injected for 7 days to pregnant female mice. The fetuses were obtained at 15, 17 and 19 dpc from both groups, also newborns (NB), neonates (7–15 days) and young adults (6 weeks of age). Histopathological exams were done on the hearts. Immunohistochemistry and western blot demonstrated GATA4 and PCNA protein expression, qPCR real time the mRNA of adrenergic receptors (α-AR and β-AR), alpha and beta myosins (α-MHC, β-MHC) and GATA4. After the administration of ISO, there was no change in the number of offsprings. We observed significant structural changes in the size of the offspring hearts. Morphometric analysis revealed an increase in the size of the left ventricular wall and interventricular septum (IVS). Histopathological analysis demonstrated loss of cellular compaction and presence of left ventricular small fibrous foci after birth. Adrenergic receptors might be responsible for changing a physiological into a pathological hypertrophy. However GATA4 seemed to be the determining factor in the pathology. A new animal model was established for the study of pathologic CH in early postnatal stages.

Cocaine Induces Cytoskeletal Changes in Cardiac Myocytes: Implications for Cardiac Morphology

“…Our result demonstrated that in response to cocaine concentrations of 10 µg/mL H9c2 cardiomyocytes underwent enhanced loss of cellular compaction and cell-cell integrity, common features of post-natal cardiac hypertrophy while doses of 1 µg/mL, appeared to cause increased cell polarity [ 29 ]. Studies performed by Badisa et al [ 24 ] suggested that the cell types examined are more inclined to withstand greater cocaine concertation, however, the present investigation indicates cardiomyocytes are more sensitive to higher cocaine concentration exposures.…”

Sphingolipid Synthesis Inhibition by Myriocin Administration Enhances Lipid Consumption and Ameliorates Lipid Response to Myocardial Ischemia Reperfusion Injury

“…After 96 h from the LAD occlusion or sham operation, the anesthetized animals and the collected hearts were weighed. Heart weight to body weight ratio (HW/BW; mg/g), a common and simple indicator of cardiac hypertrophy (Chiu et al, 2001; Sugden et al, 2008; Del Olmo-Turrubiarte et al, 2015) was calculated.…”

Functional and structural phenotyping of cardiomyocytes in the 3D organization of embryoid bodies exposed to arsenic trioxide

“…Altered expression of acta2 and myh6 , myh7 transcripts, whose impairment is associated to cardiomyocyte cell enlargement in the adult heart 37 , 45 , was found after 1.0 µM ATO exposure. In the mouse ventricle, β-MHC, coded by myh7 , is the predominant isoform in the developing heart, then replaced by α-MHC, coded by myh6 , after birth.…”

“…In the mouse ventricle, β-MHC, coded by myh7 , is the predominant isoform in the developing heart, then replaced by α-MHC, coded by myh6 , after birth. The myh6/myh7 ratio is important during cardiac development for the acquisition of proper cardiomyocyte mechanical performance and contraction efficiency 46 and its alteration is indicative of structural changes in the sarcomere structure and associated to fetal postnatal cardiac hypertrophy 45 , 46 . The altered expression of all these cytoskeleton components observed after ATO exposure might be involved in the impairment of the kinematic and dynamic properties, but also in reshaping cell morphology.…”