BioCAT, Department of Biology, Illinois Institute of Technology, Chicago, IL, USA.
Electron Microscopy Facility, UMass Chan Medical School, Worcester, MA, USA.
J Gen Physiol. 2023 Sep 4;155(9). doi: 10.1085/jgp.202313345. Epub 2023 Jul 3.
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.
对心肌的结构和功能进行研究对于深入了解心肌收缩的生理基础和心脏病的病理基础非常重要。虽然新鲜的肌肉组织最适合进行这类研究，但实际上并不总是能够获得，尤其是对于大型动物模型和人类的心脏组织。相反，冷冻的人类心脏组织库可用于转化研究，这将是一个巨大的资源。然而，目前还不太清楚液氮冷冻和低温储存对来自大型哺乳动物的心肌结构完整性可能产生怎样的影响。在这项研究中，我们直接比较了从未冷冻过的和之前冷冻过的猪心肌的结构和功能完整性，以研究冷冻和低温储存的后果。在接近生理条件下对水合组织进行的 X 射线衍射测量和化学固定的猪心肌的电子显微镜图像显示，先前的冷冻对肌肉的结构完整性只有很小的影响。此外，机械研究同样表明，冷冻和低温储存对猪心肌的收缩能力没有显著差异。这些结果表明，液氮保存是研究心肌结构和功能的一种实用方法。
