Microscopic changes of the cerebral cortex sensorimotor area under experimental hyperhomocysteinemia, hyper- and hypothyroidism and their combined influence

Abstract

Thyroid hormones are fundamental to the development of the brain and ensure its functioning throughout life.Thyroid hormones affect the development and maturation of the human brain (processing, neuronal integration, glial cell proliferation, myelination and synthesis of critical enzymes). Hyperhomocysteinemia (HHC) is a significant risk factor for cerebrovascular disease leading to stroke, Alzheimer's disease, and vascular dementia. However, only recently have experimental studies begun that examined the effects of HHC on cerebrovascular biology and the molecular mechanisms that explain these changes. The aim of the study was to establish morphological changes in the sensorimotor region of the cerebral cortex under the conditions of simulated HHC, hyper- and hypothyroidism and their combined effects. Thiolactone HHC was simulated by administering to animals exogenous homocysteine (HC) in the form of thiolactone at a dose of 100 mg/kg body weight once a day for 28 days. Hyperthyroidism was simulated by daily administration of L-thyroxine at a dose of 200 μg / kg on day 21, hypothyroidism was simulated by daily administration of mercazolyl at a dose of 10 mg/kg on day 21. Individual groups of animals were administered L-thyroxine and mercazolyl in parallel with HC. HHC was accompanied by degenerative changes in all components of the cerebral cortex. Hyperthyroidism caused destructive changes in blood vessels, major neurons, and additional glial neurons. The combination of hyperthyroidism and HHC caused more significant alternative and degenerative changes in neurons. In animals with hypothyroidism in the cerebral cortex, heterogeneous changes in neurons, color loss, and thickening of neuronal processes were found. The combination of hypothyroidism and HHC caused the most profound neurodegenerative changes in the cortex of the cerebral hemispheres.Conclusions: HHC, hyper- and hypothyroidism and especially their synergistic effects lead to neurodegenerative changes in the cerebral cortex. Against the background of significant hemodynamic changes in the body and disruption of the structure of the walls of microvessels, hyper- and hyperchromic neurons, as well as their degenerative forms, abrupt hyper- and hypochromic neurons, as well as shadow cells