Neonatal Murine Heart Slices. A Robust Model to Study Ventricular Isometric Contractions

Abstract

Background/Aims: Cardiac function is increasingly studied using murine models. However, current multicellular preparations to investigate contractile properties have substantial technical and biological limitations and are especially difficult to apply to the developing murine heart. Methods: Newborn murine hearts were cut with a vibratome into viable tissue slices. The structural and functional integrity of the tissue was shown by histology, ATP content and sharp electrode recordings. Results: Within the first 48 hours after slicing structure remained intact without induction of apoptosis. ATP concentrations and action potential parameters were comparable to those of physiological tissue. Isometric force measurements demonstrated a physiological force-frequency relationship with a ‘primary-phase’ negative force-frequency relationship up to 1-2 Hz and a ‘secondary-phase’ positive force-frequency relationship up to 8 Hz. (-)-Isoproterenol (10^-6 mol/l) increased active force to 251±35% (n=15) of baseline values and shortened relaxation times indicating a preserved beta-adrenergic regulation of contraction. Changes of the force-frequency relationship after application of ryanodine and nifedipine indicated functionality of calcium release from the sarcoplasmic reticulum and of L-type calcium channels. Conclusion: Generation of viable, physiological intact ventricular slices from neonatal hearts is feasible and provides a robust model to study loaded contractions.

Integration Properties of Wharton’s Jelly-derived Novel Mesenchymal Stem Cells into Ventricular Slices of Murine Hearts

“…Adenosine triphosphate (ATP) assays were performed on both living embryonic ventricular tissue slices, at different postoperative days, and OGD-treated slices (n=3), using a protocol previously described [35]. Briefly, ATP was quantified by a luciferase-driven bioluminescence assay (ATP-Bioluminescence Assay Kit CLS II, Roche, Germany) using a luminometer (Sirius Luminometer V2.2, Berthold Detection Systems, Germany).…”

“…Therefore, multicellular preparations with maintained cellto-cell interactions, such as tissue slices, have allowed a better understanding of the physiological mechanisms and facilitated studies of cellular function within an intact tissue [34]. The in vitro transplantation models consisting of living ventricular tissue slices derived from either embryonic [34], neonatal [35], or adult [36] murine hearts have shown morphologically conserved structures and stable electrophysiological characteristics, comparable to the in vivo counterparts. These models facilitated not only electrophysiological studies, but also studies of functional cross-talk between different cell types within the heart, at both cellular and molecular levels.…”

Report and Recommendations of the Workshop of the European Centre for the Validation of Alternative Methods for Drug-Induced Cardiotoxicity

“…Plating the slice on a microelectrode array allows mapping local activation times, detecting delays and calculating conduction velocity. Depending on the age and species of the animal used, slices can be cultured for several days to weeks to monitor long-term influence of drugs [113,114]. This allows addressing the transmural dispersion of the properties of the cardiac field potential.…”

Comparison of Depolarization and Repolarization in Mathematical Models of the Left Ventricle and the Thin Longitudinal Ventricular Slice

“…In these slices cells are exposed to more realistic electrical and mechanical interactions than in the cardiac culture, so it is believed that this pseudo-2D model represents an organotypic model of the heart [1]. This experimental model is utilized to study cardiac electrophysiology and calcium imaging [2,3], mechanics [4] and energetics [5], chemical interventions [6] etc.…”