Вплив гіпертиреозу на процеси навчання та стан гліальних проміжних філаментів головного мозку щурів

Abstract

The influence of hyperthyreosis on oxidative stress, state of glial intermediate filaments and memotry was investigated. Significant increasing of lipid peroxidation products into both hippocampus and cortex and change for the worse of memory was observed. Analysis of the behavioral reactions of rats in the test of passive avoidance conditioned reflex showed that the acquisition of skills of all groups of animals did not differ by time waiting period (latent period). Time saving memory test conditioned reflex of passive avoidance was excellent in the group of rats treated with thyroxine compared with controls. The change of polypeptide GFAP was observed in hippocampus and cortex. Both soluble and filamentous forms of GFAP increased in hippocampus of rat with hyperthyreosis. In filament fractions, increase in the intensity of 49 kDa polypeptide band was found. In the same fraction of insoluble cytoskeleton proteins degraded HFKB polypeptides with molecular weight in the region of 46–41 kDa appeared. Marked increase of degraded polypeptides was found in the soluble fraction of the brain stem. The intensity of the intact polypeptide (49 kDa), as well as in the filament fraction, significantly increased. It is possible that increasing concentrations of soluble subunits glial filaments may be due to dissociation of own filaments during the reorganization of cytoskeleton structures. Given the results of Western blotting for filament fraction, increased content of soluble intact 49 kDa polypeptide is primarily the result of increased expression of HFKB and only partly due to redistribution of existing filament structures. Calculation and analysis of indicators showed high correlation between the increase in content and peroxidation products of HFKB. These results indicate the important role of oxidative stress in the induction of astroglial reactive response under conditions of hyperthyroidism. This data shows the possibility of the glial cell cytoskeleton reconstruction under effect of thyroid hormones.