OBSERVATION ON ULTRASTRUCTURE OF NORMAL AND ISCHEMIC DOG MYOCARDIA BY FREEZEETCHING METHOD / 解剖学报

ABSTRACT

The normal and ischemic dog myocardia were treated with freeze-etching method and observed by transmission electron microscope, with special reference to the ultrastructural changes of myocardial cell membrane.Following 6 hours of coronary occlusion, the myocardial samples were taken from central and borderline ischemic areas as well as from distant normal area. The samples were cut into slices of about 1.5?1.5?3 mm~3 in size and proceeded by the routine freeze etching procedure.The myocardial cell membrane were fractured into the P face and E face. In normal myocardial cell membrane, the number of intramembranous particles of the P face was exceedingly larger than that of the E face. There were numerous caveolae appearing as depressions on the P face and elevated structures on the E face. In central and borderline ischemic areas, intramembranous particles were significantly decreased and aggregated. Following coronary occlusion, the caveolae of the myocardial cell membrane were found to be decreased, deformed or absent. In the severe ischemic area, spherical elevations with "rosette" configuration were occasionally observed as elevation on P face and depressions on E face.