Reactions of astrocytes and microglia of the sensorimotor cortex at ligation of the carotid artery, sensitization of the brain antigen and their combination

Abstract

The aim of the work is to identify changes in the state of astrocytes and microglia with unilateral ligation of the carotid artery, sensitization with the cerebral antigen and their combination in the sensorimotor cortex in rats. Studies were performed on 185 male Wistar white rats weighing 260-290 g. The brain was examined 1, 3, 10, 30 and 90 days after surgery and, respectively, 12 (1), 15 (3), 22 (10 ), 42 (30), 102 (90) days after sensitization (surgical intervention). Immunohistochemical reactions were carried out in accordance with the manufacturer’s protocols. Primary antibodies were used in the work: S100 (Dako, Denmark); GFAP (Dako, Denmark), Iba-1. Densitometric measurements of S100 expression were performed using ImageJ 1.46 and counting the number of labeled GFAP and Iba-1 cells. Statistical processing was performed using t-student test. In general, the observed reactions suggest that with discirculatory disturbances in the brain in rats, the detected changes in astrocytes and microglia tend to reverse. This can be explained by the fact that the animals used in the experiment were practically healthy and had high compensatory-adaptive potencies. In humans, a similar reverse development of glial reactions cannot be expected, since cerebral hypopefusion / dyscirculation develops against the background of changes in the vascular bed, which, as a rule, also progress. Accordingly, similar changes in human glia of the brain will act as secondary factors contributing to neurodegenerative processes. Comparatively small hemocirculation disorders in the brain with unilateral ligation of the carotid artery can cause activation of astrocytes and microglia. In this case, the reaction of astrocytes detected by the expression of GFAP is more pronounced than Iba 1 + cells. Perhaps this is due to the close contact of astrocytes with blood vessels. A significant role in glia changes is played by sensitization by cerebral antigens, which develops with impaired hemocirculation in the brain and potentiates the damage caused by it. When extrapolated to humans, it can be assumed that sensitization can make a significant contribution to the development of brain damage in conditions associated with hypoperfusion