The structural and functional integrities of porcine myocardium are mostly preserved by cryopreservation

Our current comprehensive structural and functional study validates the use of liquid nitrogen-frozen and cryostored porcine myocardium as an excellent test bed for biophysical studies of cardiac muscle that may lead to more consistent experiment results requiring reduced numbers of animals. Structural and functional studies of heart muscle are important to gain insights into the physiological bases of cardiac muscle contraction and the pathological bases of heart disease. While fresh muscle tissue works best for these kinds of studies, this is not always practical to obtain, especially for heart tissue from large animal models and humans. Conversely, tissue banks of frozen human hearts are available and could be a tremendous resource for translational research. It is not well understood, however, how liquid nitrogen freezing and cryostorage may impact the structural integrity of myocardium from large mammals. In this study, we directly compared the structural and functional integrity of never-frozen to previously frozen porcine myocardium to investigate the consequences of freezing and cryostorage. X-ray diffraction measurements from hydrated tissue under near-physiological conditions and electron microscope images from chemically fixed porcine myocardium showed that prior freezing has only minor effects on structural integrity of the muscle. Furthermore, mechanical studies similarly showed no significant differences in contractile capabilities of porcine myocardium with and without freezing and cryostorage. These results demonstrate that liquid nitrogen preservation is a practical approach for structural and functional studies of myocardium.

Automated summary

Our study validates the use of liquid nitrogen-frozen and cryostored porcine myocardium as a test bed for biophysical studies of cardiac muscle, which can lead to consistent results with reduced animal usage. These studies are important for understanding the physiological and pathological aspects of heart muscle. Liquid nitrogen preservation is a practical approach for structural and functional studies of myocardium.