Influence of the age of rats treated with the sodium salt of glutamate acid on the reactivity of astroglia of the infundibular nucleus

Abstract

The aim of the study was the immunohistochemical evaluation of the impact of the age of animals treated with the sodium salt of glutamic acid on the behaviour of astrocytes of the infundibular nucleus (IN). Immunohistochemical peroxidase-antiperoxidase reactions were conducted on brain sections of 10-day-old (I) and 63-day-old (II) rats treated s.c with monosodium glutamate (MSG) in a dose of 4g/kg b.w. for three consecutive days. The staining was performed using specific antibodies against glial fibrillary acidic protein (GFAP), S-100β protein and Ki-67 antigen. Cells immunopositive for the proteins under investigation were assessed morphologically and morphometrically in an Olympus BX51 light microscope with the Cell ^ D program. Statistically significant differences were tested using ANOVA and the non-parametric Kruskal-Wallis test. In the infundibular nucleus of 10-day-old rats treated with MSG, there was an increase in the number of GFAP, S-100β and Ki-67 immunopositive astrocytes without any changes in their morphology, which was typical of immature glia. In adult rats treated with MSG, a decrease in the number of cells expressing GFAP and S-100β was found. Most astrocytes had thick and weakly branched processes, in contrast to those observed in control animals. The results of our study showed a diverse behaviour of astroglia of IN in young and adult rats treated with MSG. In 10-day-old rats, hyperplasia of glia occurred, whereas in 63-day-old individuals there was a loss and hypertrophy of astrocytes, which may indicate a late stage of their reactivity. This information may contribute to targeting the therapy of diseases of the nervous system induced by the excitotoxic effects of glutamate.