Гистобиохимические признаки апоптоза в тканях сусликов при пробуждении после спячки

Abstract

Histological preparations of ground squirrel liver, heart and brain tissues were studied in the middle of the hibernation bout (body temperature of 1–4 °C), at self-heating (body temperature of 6–29 °C) and upon complete awakening (body temperature of 37–38 °C). In the state of deep hibernation, no signs of apoptosis were identified in ground squirrel tissues. We observed microcirculatory dysfunction manifested in abnormal blood rheology: acute hyperaemia of brain and myocardial capillaries, central veins and sinusoids of the liver, as well as mild tissue oedema and aggregations of red blood cells (rouleaux) in microvasculature. At self-heating, signs of the initial stage of apoptosis were detected: mild granularity in cardiomyocyte cytoplasm as a sign of protein dystrophy, and mild cytoplasmic vacuolization in hepatocytes. Morphological signs of these processes were revealed upon the animal’s complete awakening. Shrinkage of individual hepatocytes was observed; cells with pyknotic nuclei appeared, which can be explained by the condensation of chromatin and intracellular organelles; cell fragments with karyorrhectic phenomena resembling apoptotic bodies were identified. Thus, no signs of apoptosis were found in ground squirrel tissues during deep hibernation. At self-heating, signs of the initial stage of apoptosis were detected, and only in the state of complete awakening were single hepatocytes and neurons similar to apoptotic bodies identified. In addition, the absence of an inflammatory reaction in the tissues under study allows us to suggest that we are observing the stages of apoptosis. Noteworthy, ground squirrel awakening was accompanied by a significant increase in the activity of lysosomal membrane markers cathepsin D and acid phosphatase.