Dynamics of ultrastructural changes in glial cells and nerve fibers of the optic nerve of rats after intra-abdominal injection of a mixture of 40% Ethanol solution and 100% Methanol

N.I Molchaniuk

doi:10.31393/morphology-journal-2021-27(3)-07

Abstract

There are, quite often, cases of poisoning of human population with poor-quality alcoholic drinks, which include methanol. The optic nerve, retina and brain tissues are initially affected. A long-term study aimed at identifying initial structural changes in the visual analyzer in the application of various doses of methanol and its mixture with ethanol was carried out. Purpose: to study the dynamics of ultrastructural changes in glial cells and nerve fibers of the optic nerve, which are caused by mixture of ethanol 40% and methanol 100% in a ratio of 3:1 with a dose of methanol of 0.75 g/kg of rat weight. We examined the ultrastructure of the orbit part of the optic nerve of 43 adult rats (Wistar line) in the period from 3 hours to 14 days after one-time intra-abdominal injection of ethanol 40% and methanol 100%, 100% methanol, the dose of methanol is 0.75 g/kg of rat weight. In rats, LD50 is 9.5 g/kg of their weight. It was found out, that within 3 hours after the injection of the mixture of alcohols, the myelin sheath of large-caliber nerve fibers exfoliated, the axoplasm swelled and the mitochondria in their axons pathologically changed, the mitochondria altered in glial cells, which influenced the quality of nerve impulses and axoplasmic transport of substances. In the dynamics of the study, alterative changes in structures of the optic nerve progressed with the complete destruction of part of glial cells by 7 days, mainly in the first 3 days. After the use of methanol 100%, changes in structures of the optic nerve were similar to changes in them after the use of a mixture of alcohols, but with more significant pathology at all periods of observation with the peak of their manifestation on the 7th day. In glial cells and axons of nerve fibers from the 1st day of the study, signs of compensatory and restorative processes were found: they increased protein-synthesizing and energy-forming functions that were aimed at restoring the damaged ultrastructure. It is established, that 3 hours after the injection of a mixture of alcohols, reactive changes in the structures of the optic nerve of rats took place, which from the 1st day develop into pathological changes and are observed up to 14 days with the peak of their activity on the 7th day of the study. After the use of methanol 100%, the ultrastructure of the optic nerve of rats is more damaged than after the injection of a mixture of alcohols. It is proved, that methanol has a leading place in the development of pathological changes in structures of the optic nerve after the injection of a mixture of alcohols.

Highlights

Methanol, which is a highly toxic alcohol, is being introduced into many spheres of life, in particular, for the production of low-quality alcoholic beverages
We previously found that a single intra-abdominal injection of rats 100% methanol at a dose of 0.75 g/kg body weight, which is 10 part of the lethal dose, causes in optic nerve (ON), primarily changes in the myelin sheaths of nerve fibers of large caliber already in the first hours of observation [6]
The changes that were characteristic of the previous period were supplemented by stratification of the myelin sheath of almost all nerve fibers (NF), edema of the axoplasm and its detachment from the myelin sheath o f some NF, pathology of mitochondria and a decrease in the number of structures in the axons

Summary

Introduction

Methanol, which is a highly toxic alcohol, is being introduced into many spheres of life, in particular, for the production of low-quality alcoholic beverages. W hen using methanol up to 10 ml, blindness occurs, and when using it in a dose of 30-50 ml - death. In this regard, it is important to study the initial ultrastructural changes in the toxic effects of methanol on organs and systems of the human body in order to invent effective and targeted methods of treatment of its victims. Acute methanol poisoning can cause hemorrhage in the brain [2]. According to clinical data [21, 24, 27] in acute methanol poisoning there is optic nerve

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