Morphological changes in the heart in experimental aspiration injury

Abstract

The article examines selected morphological aspects of cardiac changes in experimental animals following aspiration of acidin-pepsin into the respiratory tract. Outbred white rats were used as the study subjects and were allocated according to the matched–pairs principle into experimental and control groups. On day 21, the animals were withdrawn from the experiment. Histological sections were prepared using a rotary microtome (paraffin sections 5–7 μm thick), followed by hematoxylin and eosin staining, mounting in a low-viscosity acrylic mounting medium (Vitrogel), and microscopic examination. All rats exhibited damage to the bronchial and bronchiolar mucosa, inflammatory cellular infiltration, circulatory disturbances, and the development of atelectasis, distelectasis, and emphysema. Against the background of aspiration pneumonia, 8% of experimental animals showed pronounced changes in the valvular apparatus; signs of cardiomyocyte hypertrophy with interstitial edema were detected in 24% of cases; and 20% of rats demonstrated signs of myocardial dystrophy in combination with stromal alterations and microcirculatory disorders. Histological examination revealed inflammatory reactions of varying severity in all layers of the heart in 46% of the experimental animals. The release of inflammatory mediators following acidin-pepsin aspiration may lead to damage to the endocardium, cardiac valve apparatus, myocardial tissue, as well as disturbances in the microcirculatory system.