P265Cardiac microhemocirculation in experimental myocardium necrosis

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Abstract

Experimental necrosis of cardiac muscle is used as the model of myocardium infarction for the studies, aimed to the investigation of heart remodeling and pre-clinical trials of preparations with cardiotropic effect. The research aim is to examine heart microcirculatory channel under experimental necrosis of myocardium. The research is performed in 110 breedless male rats of 180-250g. Experimental necrosis of cardiac muscle was modeled by two ways: ligature of left coronary artery (group 1) and cryoeffect on left ventricle wall for 15 sec (group 2). Cryoeffect was done by nitrogen cryoinstrument with 3 mm's applicator diameter at temperature of its operating surface of -196°C. Vital microscopy of heart was performed by means of contact microscope LUMAM K-1 (LOMO, Russia) in luminescence regimen after intravenous introduction of sodium fluorescein. Myocardium necrosis in rats was recorded with electrocardiographer (Polyspektr-8/B, Russia). The most manifested differences in hemodynamics and microstructure of animals' myocardium of the groups 1 and 2 were found to the 14th day. In a central zone of myocardium necrosis in animals of the group 2 there were observed single vessles of small diameter, forming atypical picture for the heart. Along the perimeter the necrosis zone was surrounded by microvessels of bigger diameter versus the norm. In the animals of group 1 the zone of ischemic necrosis was surrounded by the net of newly formed microvessels with chaotic architecture. In the animals of group 1 the diameter of myocardium capillary of right ventricle in 1 hr after surgery reduced by 17% and in animals of the 2nd group it decreased by 36% if compared with the norm (8.49 + /-0.09 micron). To the 14th day the animals of group 1 versus to the rats of group 2 the diameter of microvessels and relative area of vascular channel (0.48 + /-0.11) returned to initial values. Conclusion. In microhemocirculatory channel of heart during all observation terms after myocardium necrosis remodeling there were observed significant changes. Remodeling of vascular channel of heart depends on the way of myocardial injury.

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