Abstract
The issues of brain morphogenesis during the early postnatal period and the effect of perinatal hypoxia thereupon, which can lead to the development of neuropsychic pathology, are among the major medical and social challenges. It is well known that the nucleoli of neocortical neurons synthesize ribosomal subunits and are involved in various morphogenetic processes. When studying the effect of perinatal hypoxia on the developing brain in the model of neonatal encephalopathy, we revealed ultrastructural changes in the nucleoli of neocortical neurons and in the numerical ratio of their types, granular and reticulated. In control rats, as they developed in the neonatal period, there was an increase in the number of both granular and reticulated nucleolar types, which may be explained by a ribosomal RNA (rRNA) processing. By the end of the neonatal period, the granular agglomerates (ribosomal subunits) appeared near the nuclear membrane, probably be due to differentiation of nerve cells and biogenesis of the rough endoplasmic reticulum. In the present work, we established the fact of changing the numerical ratio of the granular and reticulated nucleolar types in the nuclei of neocortical neurons after perinatal hypoxic exposure in experimental vs. control rats. Our data suggest that the nucleoli in neocortical neurons are the targets for perinatal hypoxia, probably representing an intermediate link in the pathogenesis of the disease. Post-hypoxic administration of Phenibut (a GABA derivative, nootropic drug) corrected the pathogenetic effect of perinatal hypoxia by restoring the numerical ratio of the nucleolar types in neocortical neurons, which is typical of control rats. We assume that Phenibut can exert a neuroprotective effect through its ability to affect the nucleolar ultrastructure in neocortical neurons.
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This work was supported by the Russian Foundation for Basic Research (RFBR); grant no. 20-015-00052.
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Conceptualization and experimental design (V.A.O., L.I.Kh.); data collection (L.I.Kh., T.T.Sh.); data processing (V.A.O., E.A.V., T.T.Sh.); manuscript writing and editing (V.A.O.).
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All experimental procedures complied with the international Guidelines of Using Animals in Scientific Research and requirements of the EU Council Directive 1986 (86/609/EEC) on the use of laboratory animals. The protocols were approved by the Committee on the humane animal care at the Pavlov Institute of Physiology.
This study did not involve human subjects as research objects.
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The authors declare that they have no conflict of interest related to the publication of this material.
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Translated by A. Polyanovsky
Russian Text © The Author(s), 2021, published in Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, 2021, Vol. 57, No. 6, pp. 494–499https://doi.org/10.31857/S0044452921050065.
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Otellin, V.A., Khozhai, L.I., Shishko, T.T. et al. Nucleolar Ultrastructure in Neurons of the Rat Neocortical Sensorimotor Area during the Neonatal Period after Perinatal Hypoxic Exposure and Its Pharmacological Correction. J Evol Biochem Phys 57, 1251–1256 (2021). https://doi.org/10.1134/S0022093021060053
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DOI: https://doi.org/10.1134/S0022093021060053