Ex vivo experiments on isolated perfused hearts from normal or pathological animals

Isolated perfused heart preparation on small laboratory animals (rat, mouse)

Isolated perfused heart preparation is a flexible model to study the metabolic, physiologic and functional alterations of heart in several cardiovascular diseases such as hypertension, heart failure, diabetic cardiomyopathy and ischemia-reperfusion injury. This model also allows to rapidly determine the protective therapeutic effects of drugs on cardiac function and metabolism. Experiments are performed on an isolated perfused heart preparation in Langendorff mode (isovolumic mode) where aorta is cannulated and perfused in a retrograde (backwards) fashion. The experiment can be done under conditions of constant perfusate flow or pressure, with various substrates, and the heart may be paced by an external stimulator. Isolated perfused hearts are submitted to either total or low-flow ischemia by reduction of the flow, and then reperfused by restoration of flow. Magnetic resonance spectroscopy (31P, 23Na) is used to follow energetic metabolism and sodium homeostasis during all the experimental time course by inserting the isolated perfused heart in a glass tube placed inside the bore of vertical supraconducting magnets (4.7 Tesla and 9.4 Tesla). A water-filled latex balloon inserted into the left ventricle measures isovolumic left ventricular pressure and heart rate. The rate pressure product (the product of heart rate and developed pressure, RPP) is used as an index of cardiac function. Coronary flow is measured by timed collection of the coronary venous effluent. In parallel, several biochemical analyses are performed in cardiac coronary effluents and freeze-clamped hearts at the end of the experiments using enzymatic assays, high performance liquid chromatography (HPLC) and Western Blotting.

Example of a typical experimental protocol

Isolated Perfused rat heart

Isolated heart in the magnetic resonance sample tube

Magnetic resonance magnet and perfusion system

Example of P-31 MRS spectrum

Evaluation of cardiac function

Here is an example of typical data obtained during an ex vivo experiment (developed pressure):

Biochemical analysis in freeze-clamped hearts

Determination of phosphocreatine and adenine nucleotides content by HPLC

Determination of amino acids content by HPLC

 

Expression of protein by Western Blotting using specific antibody

 

Also in : «Preclinical Equipement»

Bruker PharmaScan® 7T Physiological Monitoring