Structural changes and features of heat shock protein HSP70 and HSP90 expression in the pyramidal neurons of the hippocampus of rat in the experimental discirculatory encephalopathy modeling

Abstract

AbstractBackgroundThe heat shock protein (Hsp) system acts as intracellular chaperone molecules responsible for maintaining normal intracellular homeostasis by regulating the correct coagulation of newly synthesized peptides, as well as the transport and degradation of mature proteins. In addition to their role as chaperones, proteins of the Hsp family stabilize the cell membrane and inhibit the caspase‐dependent apoptosis cascadeMethodHypertensive encephalopathy was modeled on 12‐month‐old rats by the method of exposure to negative longitudinal overloads in the caudo‐cranial vector with a 9 G force for 5 minutes with 12 hours interval for 28 days. The behavioral responses, cognitive and mnestic functions, the relative number of pyramidal neurons with hyperchromic cytoplasm and shrunken perikariya, and the level of expression of heat shock proteins 70 kDa (Hsp70) and 90 kDa (Hsp90) were assessedResultAfter 28 days of exposure to 9 G negative longitudinal overloads, the rats showed functional and morphological manifestations characteristic of hypertensive encephalopathy. There was a decrease in the basic reflexes, disorders of the cognitive sphere, as well as decrease in memory and orientation‐exploratory activity. Morphological examination of the hippocampus against the background of pronounced edema revealed a significant increase in the relative number of pyramidal neurons with hyperchromatosis and perikaryon shrinkage in all zones of the pyramidal layer (p <0.01). These signs of reversible and irreversible damage were accompanied by a significant increase in Hsp70 expression, especially pronounced in the CA3 zone (p <0.01). A significant increase in Hsp90 expression was found in the CA1 zone (p <0.05)ConclusionDiscirculatory encephalopathy experimental modeling demonstrates signs of both reversible and irreversible alteration in all regions of the pyramidal layer of hippocampus. Differences in the ability of neurons of the pyramidal layer of different regions of the hippocampus to express Hsp70, Hsp90 were noted. In the CA1 and CA3 zones, compensatory reactions are more pronounced and are accompanied by a more pronounced expression of Hsp70, while in CA1, the expression of Hsp70 and Hsp90 is simultaneously enhanced