Electrocorticographic patterns and dynamics of their changes in guinea pigs with acute hepatic encephalopathy caused by β-amanitin

Introduction. The toxic effect of β-amanitine is associated with acute cerebral insufficiency, which causes the severity of the condition in the unfavorable course of phalloidin syndrome.

The aim of the research was to experimentally study the dynamics of bioelectric activity of the cerebral cortex of guinea pigs with beta-amanitine-induced hepatic encephalopathy.

Material and methods. The study was performed on 13 guinea pigs with 9-electrode epidural electrocorticographic sensors implanted in the skull. High purity β-amanitin was administered intraperitoneally to animals at a dose of 3 LD₅₀ (2.7 mg/kg). The bioelectric activity of the brain was evaluated daily in dynamics by means of logical and spectral analysis of electrocorticograms. Pathomorphological macro- and microscopic examination of dead animals was performed.

Results. A model of extremely severe poisoning of guinea pigs with 3 LD₅₀ of β-amanitin with a median life expectancy of 4.5 days, a 100% probability of terminal coma and death was obtained. General atrophy was observed at the autopsy, and brain edema and liver necrosis were observed at microscopy. Electrocorticographic monitoring revealed variants of normal brain activity in guinea pigs. After administration of β-amanitin, a stepwise acceleration process was established, followed by a slowdown in brain activity to a persistent rigid theta rhythm, its further suppression with the formation of decay patterns. The presence of waves of triphase morphology characteristic of hepatargy was revealed, which were recorded, as a rule, 2–3 days after the start of the experiment. In spectral analysis, the decrease in the dominant frequency and spectral edge of the rhythm began on day 1 of intoxication, reaching a fourfold drop on day 5 in comparison with the background.

Limitations. Changes in the electrical activity of the animals cortex were analyzed only after a single administration of β-amanitin at a dose of 3 LD₅₀: the data obtained may differ under other experimental conditions.

Conclusion. Electrocorticography is suitable for objectification of hepatargy in guinea pigs with a high translational potential for extrapolating data to humans. Characteristic changes in severe encephalopathy due to β-amanitin intoxication have been established.

Compliance with ethical standards. The experimental study was approved by an independent committee at the S.M. Kirov Military Medical Academy of the Ministry of Defense of the Russian Federation.

Authors’ contribution:
Khovpachev A.A., Skiba Ya.B., Vakhviyainen M.S. – operations on guinea pigs, conducting research, collecting and processing material, writing the text;
Ivanov I.M., Lutsyk M.A. – data analysis, editing;
Basharin V.A. – concept, design and organization of research, editing.
All co–authors are responsible for approving the final version of the article and ensuring the integrity of all parts of the article.

Conflict of interest. The authors declare no conflict of interest.

Funding. The study had no sponsorship.

Accepted: October 12, 2024 / Accepted: February 25, 2025 / Published: April 30, 2025

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