Studies of morphofunctional changes in the hippocampus using a model of impaired cerebral hemodynamics are needed for understanding the mechanisms of formation of psychoneurological deficits. The aim of the present work was to assess CNS damage and the characteristics of the expression of one of the main regulators of apoptosis – Bcl-2 – in the hippocampus of rats with impaired cerebral hemodynamics induced by repeated gravitational overloading. The study was carried out on Wistar rats which were subjected to gravitational overloading (9 g) in the caudocranial direction for two 5-min periods each day for 28 days. Psychoneurological impairments in the animals were assessed using the McGraw scale and the open field, adhesion, conditioned passive avoidance reaction (CPAR), and escape extrapolation (EET) tests. Brain sections were stained by the Nissl method and the specific numbers of neurons with signs of damage were counted. Immunohistochemical studies of the level of Bcl-2 expression assessed the relative areas of immunoreactive material in the pyramidal layer in all hippocampal fields. Gravitational overloading induced impairments to the animals’ behavior, which was expressed as low movement activity and signs of retrograde amnesia, decreased fi ne motor function, and increases in psychoneurological deficit. Histological studies identified destructive changes to vessels and increases in the specific number of pyramidal neurons with damage in all fields of the hippocampus. Fields CA2 and CA4 showed the greatest increases in the numbers of damaged neurons, along with marked Bcl-2 expression.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
K. Yu. Maksimova, N. A. Stefanova, and S. V. Logvinov, “Morphological changes to neurons in the hippocampus of rats in accelerated aging,” Byul. Sib. Med., 13, No. 1, 56–61 (2014).
Yu. M. Zhabotinskii, Normal and Pathological Morphology of the Neuron, Meditsina, Moscow (1965).
A. V. Smirnov, M. V. Shmidt, D. S. Mednikov, et al., “Structural changes in the hippocampus in rats in experimental modeling of hypertensive encephalopathy in relation to heat shock protein expression,” Vestn. Volg. Goss. Med. Univ, 60, No. 4, 90–95 (2016).
A. A. Litvinov, D. V. Kurkin, and E. V. Volotova,” Analysis of the consequences of ischemic lesions to the brain in animals. Induced by centripetal acceleration in the craniocaudal direction on the background of single doses of γ-amino- and γ-hydroxybutyric acids,” Vestn. Voenno-Med. Akad., 40, No. 4, 179–183 (2012).
M. D. Gaevyi, L. E. Nazarova, L. M. Gaevaya, and Yu. A. Ogurtsov, “Experimental modeling of hemorrhagic stroke,” Patol. Fiziol. Eksperim. Ter., 2, No. 2, 7–8 (2000).
A. V. Smirnov, N. V. Grigor’eva, M. R. Ekova, et al., “Morphological changes and serine racemase expression in rat hippocampus in conditions of combined stress,” Morfologiya, 150, No. 6, 20–25 (2016).
E. T. Rolls, “Limbic systems for emotion and for memory, but no single limbic system,” Cortex, 62, 119–157 (2015).
R. Ito and A. C. Lee, “The role of the hippocampus in approach-avoidance conflict decision-making: Evidence from rodent and human studies,” Behav. Brain Res., 15, No. 313, 345–357 (2016).
A. M. Petros, E. T. Olejniczak, and S. W. Fesik, “Structural biology of the Bcl-2 family of proteins,” Biochim. Biophys. Acta, 1644, No. 2–3, 83–94 (2004).
A. V. Smirnov, N. V. Grigor’eva, and E. V. Gorelik, A. V. “Pathological anatomy of cerebrovascular disease. Strategies for stimulation of neurogenesis,” Vestn. Volg. Goss. Med. Univ, 46, No. 2, 3–8 (2013).
S. Mukhopadhyay, P. K. Panda, N. Sinha, et al., “Autophagy and apoptosis: Where do they meet?” Apoptosis, 19, No. 4, 555–566 (2014).
A. V. Smirnov, M. V. Shmidt, D. S. Mednikov, et al., “Features of structural changes in the pyramidal layer of the hippocampus of rats in gravitational overload in the caudo-cranial direction in relation to GFAP expression,” Zh. Anat. Gistopatol., 6, No. 2, 75–82 (2017).
T. Sato, T. Miyoshi, K. Nakazawa, et al., “Refl ex response changes during hyper and microgravity,” J. Gravit. Physiol., 8, No. 1, P97– P99 (2001).
U. Marušič, R. Meeusen, R. Pišot, and V. Kavcic, “The brain in micro-and hypergravity: The effects of changing gravity on the brain electrocortical activity,” Eur. J. Sport Sci., 14, No. 8, 813–822 (2014).
S. L. Chan and V. C. Yu, “Proteins of the bcl-2 family in apoptosis signalling: From mechanistic insights to therapeutic opportunities,” Clin. Exp. Pharmacol. Physiol., 31, No. 3, 119–128 (2004).
A. V. Smirnov, M. V. Shmidt, D. S. Mednikov, et al., “Morphometric study of the hippocampus of the right hemisphere in rats with a model of hypertensive encephalopathy,” Volgograd. Nauch.-Med. Zh., 52, No. 4, 7–11 (2016).
Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 105, No. 3, pp. 339–349, March, 2019.
About this article
Cite this article
Tyurenkov, I.N., Smirnov, A.V., Mednikov, D.S. et al. Functional and Morphological Changes in the Pyramidal Layer of the Hippocampus in Rats with Encephalopathy Induced by Prolonged Exposure to Gravitational Overloading. Neurosci Behav Physi 50, 479–484 (2020). https://doi.org/10.1007/s11055-020-00923-0
- psychoneurological deficit