Doublecortin Expression in the Olfactory Bulb and Rostral Stream in Infantile Rats after Exposure to Neurotoxin

Abstract

The aim of the study was to investigate changes of neuroblasts’ numeral destiny in rats’ olfactory bulb and rostral migratory stream after neurotoxic action in infant age.Material and methods. The distribution of DCX, a marker of immature neurons, was studied to reveal the dynamics of its expression in the evolutionary period of ontogenesis in olfactory bulbs and rostral migratory stream in 30, 60, 90, and 180-day-old rats. Modeling of neurotoxic effects was carried out by three times injections of capsaicin on the 30–32 day of life in a total dose of 120 mg/kg. The material for the study was sampled on the 15-, 30- and 60th days of the experiment. The marker was detected on parasagittal paraffin sections, taking into account the layers of the olfactory bulb. The numerical density of DCX+ neurons (pcs/mm2) and their part in the total number of cells were determined.Results. The standard age indicators of the numerical density of immature neurons and their share in the cell population, as well as similar indicators for two months after toxic effects, were established. The administration of toxic doses of capsaicin causes a massive death of mature neurons. Compensatory reaction manifested by activation of neurogenesis in the brain stem niches and an increase in the numerical density neuroblasts in the rostral stream.Conclusions. Activation of neurogenesis during neurodegeneration causes an increase in the number of DCX + neuronal progenitors in the olfactory bulb after 30 days after exposure and maintaining high levels until the end of observation.