Pathogenetic features of iNOS expression in the basal magnocellular nucleus of rats against the background of experimental neurodegeneration

Aim. To characterize the features of iNOS expression in neurons of the basal magnocellular nucleus against the background of nitrosative stress during experimental colchicine-induced neurodegeneration. Materials and methods. The study was conducted on 30 male Wistar rats. At the first stage of the experiment, cognitive impairments were modeled in rats (n = 10) by intracerebroventricular injection of colchicine, and compared with sham-operated and intact animal groups, the validity of the model was demonstrated using an 8-arm radial maze LE760 (PanLab Harvard Apparatus, Spain). Subsequently, the animals were euthanized with sodium thiopental, and the brain was removed for histological, immunofluorescence, and biochemical analyses. Results. It was found that intracerebroventricular injection of colchicine compared to intact and sham-operated animals leads to disruption of histoarchitecture in the basal magnocellular nucleus of rats with a significant decrease in the Nissl substance area in neurons by 47.3 % and 35.9 %, respectively. At the same time, the level of nitrites in the brain homogenates of animals with experimental neurodegeneration exceeded the comparison groups almost 10 times (intact) and 7 times (sham-operated rats). Meanwhile, immunofluorescence investigation of iNOS expression in the basal magnocellular nucleus of rats with intracerebroventricular colchicine administration, compared to intact and sham-operated animals, revealed a significantly higher value of corrected total cell fluorescence by 22.7 % and 45.3 %, respectively. Simultaneously, it was established that experimental colchicine-induced neurodegeneration is accompanied by a significantly greater number of iNOS+ cells in the basal magnocellular nucleus compared to control groups. Conclusions. Intracerebroventricular injection of colchicine to experimental rats is accompanied by morphological signs of neurodestruction in the basal magnocellular nucleus against the background of nitrosative stress. iNOS expression in rats after intracerebroventricular colchicine administration in the cells of the basal magnocellular nucleus is characterized by a higher enzyme content compared to intact and sham-operated animals. The area of immunopositive cells between experimental groups does not change statistically. Intracerebroventricular administration of colchicine to experimental rats is accompanied by an increase in the number of immunopositive cells for iNOS in the basal magnocellular nucleus.