[Comparative aspects of structural organization of astrocytes of the first layer of the human and rat cerebral cortex].

Importance of study of astrocytes for fundamental biology and medicine is due their key role in formation of the brain barrier system. On taking into consideration the controversial data on structure of the mammalian neocortex superficial layers, of great actuality are the comparative studies of the structural and cytochemical organization of astrocytes in human and in the laboratory animals used in the experimental studies connected with modeling of brain diseases and traumas. The goal of the present work was to study structural organization of astrocytes in the human and rat neocortical layer I. The work was on the autopsy and experimental material from Wistar rats. Astrocytes were revealed immunocytochemically by using antibodies to GFAP, vimentin and nestin. The preparations were examined with aid of light and confocal laser microscopy. No significant difference in the sizes of perinuclear areas were established between the rat and human astrocytes. In the majority of cortex regions, the specter of proteins forming intermediate filaments in these cells was identical. However, there were essential differences revealed in organization of the superficial glial bordering lamina (SGBL). The human SGBL is formed by interlacing of thin processes in the layer I processes, whereas the rat SGBL is represented by specialized astrocytes spread along the cortical surface and connected with the wide-blade processes. The human layer I astrocytes have translaminar processes passing via several cortical layers, whereas in rats such processes are located within the limits of one layer. The revealed differences in the astrocyte structural organization should be taken into account when interpreting results of experimental studies carried out on rats and extrapolating these results to human.