Isolated working heart (Langendorff) method

The choice of animals used for experiments depends to a large extent upon the broad research objectives of an individual research group. Each model has disadvantages and advantages. Rodents, including mice, rats, guinea pigs, and rabbits should be anesthetized with barbiturates or ketamine and anticoagulated with heparin sodium. After thoracotomy, the heart is excised, isolated, the aorta cannulated and the heart is perfused according to the Langendorff or “working” mode approach, which was pioneered by the Tosaki Laboratory (Neely 1967; Yamamoto 1984; Tosaki and Braquet 1990). The perfusion medium used for these procedures is Krebs-Henseleit bicarbonate buffer or a modified version, with component ratios (in millimolar units) that include: sodium chloride 118, potassium chloride 4.7, calcium chloride 1.7, sodium bicarbonate 25, potassium biphosphate 0.36, magnesium sulfate 1.2 and glucose 10. The left atrium is cannulated and the Langendorff system is adapted and switched to isolated working heart monitoring mode, adapted for mice, rat, or rabbit heart experiments. The revised procedure uses a left atrial filling pressure of 17 cm (1.7 kPa) and aortic afterload pressure of 90 cm (9.0 kPa) of buffer. Cardiac functional measurements using this method, includes aortic flow (AF), measured by a calibrated flow meter (Gilmont Instruments, Barrington, Illinois, USA), and coronary flow (CF) rate, measured by timed collection of the coronary perfusate dripped from the heart.

The isolated myocardium may be subjected to normothermic or hypothermic, global or transient ischemic stress followed by reperfusion, and redox signaling. The Langendorff isolated working heart technique allows monitoring of physiologic activities of heart tissue subjected to conditions of stress, such as ischemia-reperfusion injury in the context of control conditions (Thirunavukkarasu 2008, Juhasz 2008, Juhasz 2013).