The ultrastructural features of sensorimotor cerebral cortex of rats with metabolic syndrome

Background. Metabolic syndrome (MS) is characterized by a number of pathogenetic factors that adversely affect the function of the central nervous system (CNS). The study of early stages of ultrastructural damages in the CNS in the conditions of MS is important for compensation and prevention of pathological states leading to the brain hypoxia and cognitive disorders.

Objective. The aim was to investigate the morphological characteristics of the brain tissue and the cerebral capillaries in neocortex (the I-VI layers) sensorimotor region of rats with MS induced by a long-term (15 weeks) high-carbohydrate/high-fat (HC/HF) diet.

Design and methods. The neocortex ultrastructure was investigated using an electron microscopy.

Results. The moderate destructive changes in the components of the neurovascular units of the sensorimotor region of the cerebral cortex were detected in MS rats. Regardless of the functional response of brain capillaries (vasodilatation / vasoconstriction) to systemic insulin resistance and hyperglycemia, the signs of blood-brain barrier (BBB) dysfunctions were detected in MS-rats, such as an increase in the thickness and the impaired integrity of the basement membrane, endothelial microclasmosis, edema, and the estruction of perivascular glia. The destructive changes in cerebral capillaries were combined with neuro-vasal contacts increased 2,3 times, the proportion of apoptotic neurons increased 5 times and the proportion of normochromic neurons accurately reduced by 13 %.

Conclusion. In neocortex sensorimotor region of rats with MS induced by the HC/HF diet, the moderate dysfunction of the BBB and the reactive changes in neurons and neuro-vasal contacts were shown, and the cause of which may be hyperglycemia, dyslipidemia, and systemic insulin resistance typical for MS.

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