The overactivation of inflammatory pathways and/or a deficiency of neuroplasticity may result in the delayed recovery of neural function in traumatic brain injury (TBI). A promising approach to protecting the brain tissue in TBI is xenon (Xe) treatment. However, xenon’s mechanisms of action remain poorly clarified. In this study, the early-onset expression of 91 target genes was investigated in the damaged and in the contralateral brain areas (sensorimotor cortex region) 6 and 24 h after injury in a TBI rat model. The expression of genes involved in inflammation, oxidation, antioxidation, neurogenesis and neuroplasticity, apoptosis, DNA repair, autophagy, and mitophagy was assessed. The animals inhaled a gas mixture containing xenon and oxygen (ϕXe = 70%; ϕO₂ 25–30% 60 min) 15–30 min after TBI. The data showed that, in the contralateral area, xenon treatment induced the expression of stress genes (Irf1, Hmox1, S100A8, and S100A9). In the damaged area, a trend towards lower expression of the inflammatory gene Irf1 was observed. Thus, our results suggest that xenon exerts a mild stressor effect in healthy brain tissue and has a tendency to decrease the inflammation following damage, which might contribute to reducing the damage and activating the early compensatory processes in the brain post-TBI.

An increase in the number of patients with severe brain damage of various etiologies determines the need to improve neuroprotection technologies. The review is devoted to modern views on the mechanisms of brain protection, as well as the basic processes underlying damage to neurons. The article discusses the results of the most important experimental studies in this area using inert xenon gas. The authors analyzed a number of works highlighting neurotective properties of the xenon inhalation anesthetic in studies performed in vitro and in vivo. The main mechanisms of neuronal death depending on the type of damage are shown, the points of application of the protective effect of xenon on the brain and the prospects for further research in this area are demonstrated in the article.

This is the first in vivo study to investigate the neuroprotective effects of krypton on focal cerebral ischemia. The aim of the study was to analyze the effect of 2 h of inhalation of a krypton–oxygen mixture (Kr 70%/O₂ 30%) on the recovery of neurological functions and the degree of brain damage in rats after photoinduced ischemic stroke (PIS) and to investigate the possible mechanisms responsible for this neuroprotection. Experiments were performed on male Wistar rats weighing 250–300 g (n = 32). Animals were randomized into four groups. Two groups (n = 20) underwent photoinduced ischemic stroke, followed by 2 h of inhalation of krypton–oxygen mixture consisting of Kr 70%/O₂ 30% or a nitrogen–oxygen breathing mixture consisting of N₂ 70%/O₂ 30%, followed by neurological examinations on days 3 and 7. The other two groups (n = 12) received only gas mixtures of the same concentration and exposure duration as in those in the PIS groups, then Western blot analysis of the potential molecular mechanisms was performed. The results of the study show that treatment with the krypton–oxygen mixture consisting of Kr 70%/O₂ 30% improves the neurological status on day 7 of observation, reduces the lesion volume according to the MRI examination and the number of Iba-1- and caspase-3-positive cells in the damaged area, promotes the activation of neoangiogenesis (an increase in the von Willebrand factor), and reduces the penumbra area and the number of NeuN-positive cells in it on day 14 of observation. Inhalation of the krypton–oxygen mixture also significantly increases the levels of phosphorylated AKT kinase (protein kinase B) and glycogen synthase kinase 3b (pGSK3b) and promotes the expression of transcription factor Nrf2, which was accompanied by the lowered expression of transcription factor NFkB (p50). Thus, we showed pronounced neuroprotection induced by krypton inhalation after stroke and identified the signaling pathways that may be responsible for restoring neurological functions and reducing damage.

In vivo studies of the therapeutic effects of argon in traumatic brain injury (TBI) are limited, and their results are contradictory. The aim of this study was to evaluate the effect of a three-hour inhalation of argon (70%Ar/30%O₂) after an open TBI on the severity of the neurological deficit and the degree of brain damage in rats. The experiments were performed on male Wistar rats (n = 35). The TBI was simulated by the dosed open brain contusion injury. The animals were divided into three groups: sham-operated (SO, n = 7); TBI + 70%N2/30%O₂ (TBI, n = 14); TBI + 70%Ar/30%O₂ (TBI + iAr, n = 14). The Neurological status was assessed over a 14-day period (using the limb-placing and cylinder tests). Magnetic resonance imaging (MRI) scans and a histological examination of the brain with an assessment of the volume of the lesions were performed 14 days after the injury. At each of the time points (days 1, 7, and 14), the limb-placing test score was lower in the TBI and TBI + iAr groups than in the SO group, while there were no significant differences between the TBI and TBI + iAr groups. Additionally, no differences were found between these groups in the cylinder test scores (day 13). The volume of brain damage (tissue loss) according to both the MRI and histological findings did not differ between the TBI and TBI + iAr groups. A three-hour inhalation of argon (70%Ar/30%O₂) after a TBI had no neuroprotective effect.

Sepsis is one of the most serious problems in modern medicine. Long-term outcomes in septic shock patients are very discouraging: 75% individuals who survived sepsis and septic shock demonstrate signs of organ failure and experience persistent functional deficit. Acute sepsis and its management in an intensive care unit (ICU) to a great extent determine the pathogenesis of further complications. We believe that the concept of phenoptosis proposed by Prof. Skulachev deserves a special attention from anesthesiologists and ICU doctors. According to this concept, septic shock is a suicidal mechanism of programmed organism death, which protects human population from dangerously infected individuals. The article suggests a potential approach to the sepsis treatment based on the notion that septic shock can be prevented by identification and blockade of receptors involved in the processing of phenoptotic signal induced by lipopolysaccharide and other substances that initiate septic shock. In view of this, the search for agents that can block molecular mechanisms of the phenoptotic signal transmission seems very promising.

The aim of the study: to examine the anti-inflammatory effect of lithium chloride by exposing the human neutrophils to serum of patients with septic shockin vitro.Material and methods. The study was carried out on neutrophils extracted from the blood of 6 healthy donors, which were activated with serum from patients with septic shock. The neutrophil activity was evaluated with fluorescent antibodies to the CD11b and CD66b markers of degranulation. The level of human neutrophil apoptosis and necrosis was assessed 22 hours after extraction; quantitative assessment was made using annexin V and propidium iodide with flow cytofluorimetry. Intact and activated neutrophils were treated with 0.3, 3.0 and 9.0 mmol lithium chloride solution.Results. The level of CD11b expression on the surface of intact neutrophils (healthy donors) was 3434.50 [3311.0-3799.0] arbitrary fluorescence units (AFU). Incubation of neutrophils with serum of patients with septic shock increased CD11b expression 2.5 times to 8589.0 [7279.0-11258.0] AFU (P=0.005) vs intact leukocytes, and increased CD66b expression 2.7 times up to 27 600.0 [22 999.0-28 989.0] AFU ((P=0.005) vs intact neutrophils. Lithium chloride in concentrations of 0.3, 3.0 and 9.0 mmol in a dose-dependent manner reduced the level of expression of CD11b and CD66b molecules on the surface of activated neutrophils. Septic serum reduced spontaneous neutrophil apoptosis, and 3.0 mmol and higher lithium chloride solution induced spontaneous neutrophil apoptosis.Conclusion. Lithium chloride reduces the activation of neutrophils preactivated by serum of patients with septic shock, reduces expression of CD11b and CD66b molecules on the neutrophil surface, inhibiting the process of their activation (degranulation). Lithium chloride in concentration of 3.0 mmol and higher is able to induce spontaneous apoptosis of neutrophils activated by serum of patients with septic shock.