Details

Autor(en) / Beteiligte

• Fedorova, E. N.
• Voronkov, D. N.
• Egorova, A. V.
• Baranich, T. I.
• Glinkina, V. V.
• Germanova, E. L.
• Lukyanova, L. D.
• Sukhorukov, V. S.

Titel

Changes in the Rat Hippocampal Neurogenic Niche under Hypoxic Exposure

Ist Teil von

• Journal of evolutionary biochemistry and physiology, 2023-07, Vol.59 (4), p.1086-1099

Ort / Verlag

Moscow: Pleiades Publishing

Erscheinungsjahr

2023

Link zum Volltext

Quelle

2022 ECC(Springer)

Beschreibungen/Notizen

• The hippocampus is one of the brain structures most vulnerable to hypoxia. The cellular pool in the hippocampal subgranular zone (SGZ) neurogenic niche is maintained by the adaptive mechanisms, such as functional changes in the mitochondrial respiratory chain complexes and the reactivity of astroglia that provides structural and metabolic support for neurons. To reveal the dynamics of adaptive changes in neurons and glia of the hippocampal dentate gyrus in response to single (60 min) and repeated (8 and 20 bouts) intermittent hypobaric hypoxia exposures (5000 m equivalent to 10.5% O 2 ), the localization and content of mitochondrial respiratory Complex IV cytochrome c oxidase subunit 1 (MTCO1), astrocyte markers glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP), as well as the immature neuron marker doublecortin (DCX), were studied in low-resistant rats by immunomorphological methods. After a single hypoxic exposure, the MTCO1 content significantly increased in neurons, while after 8 hypoxic episodes, the GS level increased in astrocytes. Changes in the latter were most prominent in the astrocytic processes, indicative of hypoxia-induced GS redistribution. The number of DCX-positive neurons in the SGZ significantly decreased after 20 hypoxic episodes. At the same time, DCX-positive glia-like cells were found in the hippocampal polymorphic layer, while GFAP labeling revealed an increase in the number of astrocytes, which may be partly due to a shift in the direction of cell differentiation in the neurogenic niche. Thus, hypoxia first intensifies mitochondrial respiratory chain activity in the neurons of the hippocampal granular cell layer, followed by the activation of astrocytes that modulate glutamate metabolism. The relationship between the dynamics of adaptive energy metabolism reactions in neurons and glia and changes in neurogenesis after 20 hypoxic episodes suggests that repeated (long-term) hypoxia promotes a shift in the differentiation of SGZ neural progenitors toward astroglia. However, this issue requires further investigation to identify the nature of DCX-positive cells more accurately.