Morphological and morphometric description of neurons in the sensorimotor cortex of the rat brain after ligation of the common carotid arteries

Abstract

The aim of the study was to present structural and morphometric changes in the sensorimotor cortex neurons of the rat brain after ligation of the common carotid arteries (LCCA).Material and methods. Cerebral ischemia was modeled in white Wistar rats by irreversible bilateral ligation of common carotid arteries (2-vessel model of incomplete global ischemia, without hypotension). For morphological studies, histological (hematoxylin–eosin, thionin staining according to the Nissl method), immunohistochemical (NSE, GFAP) and morphometric methods were used. The control group consisted of intact animals (n=6), the material was taken 1, 3, 7, 14 and 30 days after the experimental modeling of LCCA (n=30). Morphometric analysis was performed on preparations of frontal sections of the brain using the ImageJ 1.53; statistical hypotheses were tested using the Statistica 8.0.Results. It was found that the number density of normochromic neurons decreased throughout the study period and reached its minimum values 30 days after LCCA: the decrease in layer III was 75.9%, and in layer V it was 72.6%. There was a decrease in the total number density of neurons. After 1 and 3 days, in layers III and V, the content of hyperchromic neurons with intact shape of perikarya increased. The numerical density of hyperchromic neurons with a spindle-shaped perikaryon, a deformed nucleus, as well as neurons with a homogeneous cytoplasm had maximum values after 30 days.Conclusion. After irreversible bilateral LCCA, together with an increase in the number density of hyperchromic pycnotic neurons, as well as neurons with homogenization of the cytoplasm and nucleus, a decrease in the NSE content in the cytoplasm of pyramidal neurons was noted, which may indicate a decrease in the expression of this protein and a decrease in the functional activity of neurons by the end of the study period. An increase in hyperchromic pycnotic neurons and shadow cells against the background of a decrease in the number density of normochromic and hyperchromic non-pycnotic neurons may indicate a significant severity of the processes occurring after LCCA and the irreversibility of destructive changes in nerve cells.