An isolated retrograde-perfused newborn mouse heart preparation

Abstract

The Langendorff-perfused model is a powerful tool to study biological responses in the isolated heart in the absence of confounders. The model has been adapted recently to enable study of the isolated mouse heart and the effects of genetic manipulation. Unfortunately, the small size and fragility of the mouse heart pose significant challenges, limiting application of the Langendorff model to the study of adult mice. Cardiac development is a complex and dynamic process that is incompletely understood. Thus, establishing an isolated-perfused heart model in the newborn mouse would be an important and necessary advance. Here we present a method to successfully cannulate and perfuse the isolated newborn murine heart. We describe the basic and fundamental physiological characteristics of the ex-vivo retrograde-perfused beating neonatal heart in wild-type C57Bl/6 male mice. Our approach will enable future study of the physiological and pharmacological responses of the isolated immature murine heart to enhance knowledge of how developmental cardiac biology impacts health and disease.•The Langendorff model is a powerful tool to study the heart without confounders.•An isolated-perfused newborn murine heart model has yet to be established.•We demonstrate the first successful isolated neonatal murine heart preparation.

Keywords: Cannulation; Heart; Isolated; Langendorff; Model; Mouse; Newborn.

Graphical abstract

Fig. 1

The Isolated Retrograde-Perfused Newborn Mouse Heart. An image of a 10-day old mouse heart following successful cannulation with a 26-gauge blunt needle is depicted. Coronary effluent was permitted to freely drip from the heart through the incised right atrium. Stainless steel surface electrodes coated with blue polyethylene are seen contacting the heart. Surface ECG and ventricular contractile force were continuously measured and recorded and representative tracings are demonstrated. Heart rate in the depicted example is 194 beats·min⁻¹ and rhythm is clearly sinus. The supplemental video demonstrates a 5–0 silk suture connected between the apex of the beating heart and a force displacement transducer to quantify isometric tension.