Toxic effects of oxygen and how to deal with them in a critical condition. A view from the standpoint of pathophysiology

Hypoxia, as a typical pathophysiological process, lies in the structure of the development of a large number of critical conditions and is the main cause leading to multiple organ failure, causing fatal outcome of patients in intensive care units due to acute respiratory failure. Of course, historically there has been a mechanistic approach to the treatment of acute respiratory failure using oxygen, despite the presence of toxic effects of oxygen, especially when using high concentrations that potentiate the development of oxidative stress with characteristic antioxidant deficiency in hyperoxemia conditions. Objective. The search for materials confirming the hypothesis that the use of the natural mechanism of functioning of the succinate dehydrogenase-succinate complex makes it possible to neutralize the toxic effects of oxygen in conditions of its high concentrations due to the realization of antioxidant and antihypoxic properties characteristic of the functioning of the unique II section of the mitochondrial respiratory chain. Material and methods. The search for literature sources was carried out using the electronic resources of the Russian scientific electronic library eLIBRARY.ru, where the following keywords were used «antioxidants, antihypoxants, hyperoxemia, toxic effects of oxygen, Krebs cycle, succinate, succinate dehydrogenase, critical conditions5 September 2024 will mark the 70th anniversary of the leading aortic surgeon of our country, academician of the Russian Academy of Sciences, professor, doctor of medical sciences, director of the Institute of Cardio-Aortic Surgery of the State Research Center of the Federal State Budgetary Institution “Acad. B.V. Petrovsky” Yuri Vladimirovich Belov» and in the English-language text database of medical and biological publications PubMed, where similar keywords «antioxidants, antihypoxants, hyperoxemia, toxic effects of oxygen, Krebs cycle, succinate, succinate dehydrogenase, critical conditions». Results. A literature search allowed us to generate a hypothesis and a general biological phenomenon of the II section of the mitochondrial respiratory chain, where the composition of succinate dehydrogenase and succinate allows the implementation of an antioxidant and antihypoxant protective mechanism in hyperoxemia conditions, which avoids the toxic effects of oxygen in conditions of its high concentrations. Conclusion. The presented material indicates facts confirming the hypothesis that in hypoxia and activation of the processes of excessive synthesis of free radicals, which are catastrophic for cells in conditions of excessive oxygen supply and developing deficiency of antioxidant protection, the use of succinate is already a solved task. The presented hypothesis has been confirmed not only at the level of fundamental, but also clinical studies, and it is extremely difficult to argue with this fact today.