Ultrastructure of rat cerebral cortex cells in normal and experimental dioxin poisoning

Purpose the study of the ultrastructure of the cerebral cortex of rats in normal and experimental poisoning with dioxin. Materials and methods. We studied the ultrastructure of the cells of the pyramidal layer of the cerebral cortex of rats of the control and experimental groups that were chronic poisoned with small doses of dioxin (2,3,7,8-tetrachlorodibenzo-para-dioxin or TCDD). Morphometric analysis was carried out to determine the length of synaptic clefts, the number of synapses per unit area, the thickness of the myelin layer of the processes and the number of wrappers of myelin sheaths. Results. The pathology of neurons has been observed both at the optical and ultrastructural levels. It is characterized by a decrease in nuclei, cell death, thinning of myelin sheaths and demyelination. The dose of poisoning correlates with the degree of destruction of neurons: with an increase in the dose of dioxin, changes become more significant. The number of synaptic contacts decreases but there is a significant increase in their average length. Conclusions. The processes of demyelination, impaired cellular respiration and destruction of synaptic contacts indicate the ability of dioxin to indirectly cause accelerated aging of neurons and their death (apoptosis).