Ultrastructure of cultured adult myocardial cells during anoxia and reoxygenation.
Cultured heart cells from adult rats were exposed to anoxia in a substrate-free Tyrode's solution at constant pH. In this system the metabolic and the morphologic pattern can be investigated simultaneously. Anoxic changes develop gradually above 2 mumol adenosine triphosphate (ATP)/ gww . Morphometry reveals that the morphologic changes are closely related to the energetic state: creatine phosphate (CP) decay is accompanied by the loss of small mitochondrial matrix granules (r = 0.97). The fall of ATP is coincident with sarcomere shortening (r = 0.95) and, below 4 mumol/ gww , with mitochondrial swelling (r = -0.88). The number of lipid droplets correlates with the ATP level during anoxia and reoxygenation (r = -0.92). The early energetic depletion is accompanied by a moderate release of cytosolic enzymes and morphologic changes: the appearance of sarcolemmal microblebs and an increase in subsarcolemmal vesicles. Below an average ATP level of 2 mumol/ gww an increasing number of individual cells fail to recover when reoxygenated . However, that failure is accompanied neither by massive enzyme release nor by ultrastructural damage regarded as typical for the "oxygen paradox."
D000818:Animals; D002452:Cell Count; D002478:Cells, Cultured; D004734:Energy Metabolism; D005260:Female; D006352:Heart Ventricles / Q000378:metabolism / Q000648:ultrastructure; D000860:Hypoxia / Q000378:metabolism / Q000473:pathology*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure*; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains