Increased survival of aquarium fish under acute hypoxia induced by prior intragastric administration of hydrogen peroxide
Authors: Fisher Evgeny L. , Urakov Aleksandr L. , Shabanov Petr D. 
Published: October 2024

BACKGROUND: A solution of 3% hydrogen peroxide is an over-the-counter oxygen-releasing antiseptic, which forms oxygen foam when interacting locally with the wound surface. Therefore, this drug is widely used for mechanical cleansing of the surface of chronic wounds from purulent masses. The release of oxygen during catalase cleavage of hydrogen peroxide indicates the possibility of achieving anti-ischemic and anti-hypoxic action.
AIM: A study of the effect of intragastric hydrogen peroxide on the resistance of aquarium fish to acute hypoxia.
MATERIALS AND METHODS: Experiments were conducted on 80 adult aquarium fish of the guppy, blue neon, tri-linear parsings, swordtail fish and zebrafish (Danio rerio) breeds. To create acute hypoxia, each fish was placed in a transparent plastic container containing 5, 10 or 20 ml of fresh water at a temperature of +25 - +26 °C together with the fish, after which the container was hermetically sealed. Then, the motor activity of the fish's body, the respiratory movements of the gill arches, the opening of the oral cavity, the fluctuations of the fins and the dynamics of their coloration were monitored until the complete final immobilization of the fish and their death. Immediately before the experiment, 0.05 or 0.1 ml of fresh water in the control series and 0.05 ml or 0.1 ml of 0.05% hydrogen peroxide solution in the experimental series were injected into the stomach of the fish. The liquid was injected into the fish's stomach using a gastric mini-probe connected to an insulin syringe.
RESULTS: It is shown that aquarium fish retain their viability in a small volume of fresh water inside a hermetically sealed container for a limited period of time, since fish continuously consume oxygen dissolved in water, thereby deepening hypoxia. At the same time, after sealing the container, the fish very quickly assume a stationary state, in which they remain for a certain period of time until their death. However, just before death, the immobility of the fish is disturbed. At the same time, the fish suddenly appear convulsive body movements, active movements of pectoral fins, mouths and gill arches, pectoral fins change their color, after which the fish defecate into the water. The results showed that the preliminary injection of 0.05 or 0.1 ml of 0.05% hydrogen peroxide solution into the stomach of fish prolongs the period of immobility of fish in hypoxia by an average of 20%. In all likelihood, the immobile state of fish is part of the complex of their adaptive adjustment to the cessation of oxygen supply to the water and reflects the availability of reserves of adaptation to hypoxia. The fact is that the absence of muscle contractions stops the muscles from using oxygen, which they use to generate energy. It is assumed that inside the stomach, hydrogen peroxide is absorbed into the blood, where, under the action of the enzyme catalase, it is split into water and gaseous oxygen, which replaces oxygen in the gills in the absence of oxygen in the surrounding water.
CONCLUSIONS: Under model conditions, it was shown that pre-administration of 0.05 or 0.1 ml of 0.05% hydrogen peroxide solution into the stomach of fish increases their survival in conditions of acute hypoxia. Therefore, hydrogen peroxide can be considered as a potential antihypoxant for prolonging life in various types of suffocation, including the final stage of COVID-19.