The role of oxidative stress in hemorrhagic stroke and restorative effects of Mexidol


Zakusov Institute of Pharmacology, Moscow, Russia

Objective. Identification of the role of oxidative stress in the development of disorders that occur in hemorrhagic stroke (HS, post-traumatic intracerebral hematoma), and the study of the effects of Mexidol on neurological and cognitive deficits in HS with an analysis of the relationship between the therapeutic effects of the drug in HS with its antioxidant effect. Material and methods. The study was carried out on mature outbred male rats weighing 260—280 g. HS was created by destruction of the brain tissue in the area of the capsula interna, with the introduction of blood into the site of injury. On the 1st, 7th, and 14th days after HS modeling, death, neurological deficits (McGrow scale, rotating rod), convulsive manifestations, and cognitive impairment were recorded in rats; blood plasma and homogenates of the cerebral cortex of rats. Mexidol was administered after the HS operation: first at a dose of 150 mg/kg, intraperitoneally, for 3 days and then 75 mg/kg, orally (from the 4th to the 14th day). Results. Mexidol in rats with HS significantly increases the survival rate of animals, reduces the manifestations of neurological deficits according to the McGrow scale (playpen movements, paresis of 1—4 limbs, paralysis of the lower limbs, lateral position), eliminates individual motor convulsive manifestations, restores impaired coordination of movements (rotating rod test) and improves, impaired HS, learning and memory processes. Mexidol normalizes the concentration of TBA-active products in the blood of animals and homogenates of the cerebral cortex of rats, both a day and 7 days after HS modeling. Conclusion. The data obtained indicate the involvement of oxidative stress as a chain of pathogenesis in the development of disorders in HS and the ability of Mexidol to alleviate neurological deficits, convulsive manifestations and cognitive impairment in HS, which is accompanied by a decrease in oxidative stress. All this justifies the importance of the use of Mexidol in patients with hemorrhagic stroke, posttraumatic intracerebral hematoma and determines the features of its therapeutic effects.

Keywords: hemorrhagic stroke, intracerebral hematoma, oxidative stress, Mexidol, neurological deficit, seizures, cognitive impairment.

Antioxidant activity and toxicity of ethylmethylhydroxypyridine succinate and edaravone: comparative in vitro experiment


Ryazan State Medical University, ul. Vysokovoltnaya 9, Ryazan, 390026 Russia

The cytotoxic effect and antioxidant activity of ethylmethylhydroxypyridine succinate (EMHPS) and edaravone were compared in a concentration range of 5 – 5000 mM. The cytotoxic effect was assessed on the HEK293 cell line using the MTT test. The oxidative stress (OS) was modeled by incubation of cells with hydrogen peroxide (Н2О2) at a concentration of 5 mM for an exposure duration of 24 h. The antioxidant activity of both substances was analyzed using their effects on the level of carbonyl derivatives of proteins and TBA-reactive products in the lysate of HEK293 cells. EMHPS reduced the viability of cells only at a concentration of 5 mM to 64.46 + 9.17% (p = 0,021), while edaravone was effective at concentrations of 5, 1, and 0.5 mM by reducing the viability of
cells to 44.55 + 7.43% (p = 0,008), 57.11 + 11.79% (p = 0,013), and 67.97 + 28.07% (p = 0,059), respectively. The OS modeling was accompanied by decrease in the viability of cells to 24.50 + 14.14% (p = 0,033). Both EMHPS and edaravone at concentrations of 50 and 100 mM prevented decrease in the cell viability under OS conditions. However, the EMHPS effect at a concentration of 100 mM was stronger by 30.6% ( p = 0.054) than that of edaravone at a similar concentration in reducing the content of carbonyl derivatives of proteins in the cell lysate. At concentrations of 100 and 50 mM, EMHPS decreased the level of TBA-reactive products in the lysate also stronger than did edaravone – by 43.8% ( p = 0.003) and 38.7% ( p = 0.05), respectively. Thus, results of this study show that EMHPS is a less toxic substance and has more pronounced antioxidant properties in comparison to edaravone.

Keywords: ethylmethylhydroxypyridine succinate; edaravone; oxidative stress; hydrogen peroxide; HEK293 cell line; toxicity; viability.

Role of free radical oxidation, hypoxia and their correction in COVID-19 pathogenesis


Academician I.P. Pavlov Ryazan State Medical University of the Ministry of Healthcare of Russia

In following review, the pathogenesis of coronavirus disease of 2019 (COVID-19), the features of the SARS-CoV-2 virus, are shown in peculiarities. Due to big importance of oxidative stress and hypoxia in the development of this infection paid to, it has been suggested that the use of antioxidants and antihypoxants in the complex treatment of COVID-19 may be useful and significantly improve the course of the disease.
Key words: COVID-19, coronaviruses, oxidative stress, hypoxia.

Geroprotective effects of ethylmethylhydroxypyridine succinate in an experimental study


FSBI «Zakusov Institute of Pharmacology», Moscow

Objective. To study an effect of mexidol on the life expectancy, weight, seizure response thresholds, and impaired cognitive and
motor functions during aging in male Wistar rats. Material and methods. In a long-term experiment, male Wistar rats, aged 3—26 months, were assessed for impaired cognitive functions (passive avoidance conditioned reflex test), convulsive threshold (test with pentylenetetrazole), motor deficits (tests of rotating rod and pulling on the crossbar), and life expectancy. The rats received mexidol in the form of 0,15% solution, which replaced drinking water, during two 2 month courses at the age of 18—20 and 22—24 month. A dose of mexidol consumed by the rat was 40-75 mg/kg/day. Results. In old male Wistar rats, the long-term treatment with mexidol increases the life expectancy, improves learning, preservation and reproduction of the memory trace in the passive avoidance conditioned reflex test, increases the convulsive threshold and improves muscle tone and coordination of movements that are impaired during aging. Conclusion. Mexidol increases the threshold of convulsive reaction, restores cognitive and neurological deficits that occur during aging in male Wistar rats and increases the by its ability to influence mitochondriogenesis and antioxidant properties.
Keywords: aging, mexidol, life expectancy, memory impairment, neurological deficit, convulsive threshold.

The effect of Mexidol on cerebral mitochondriogenesis at a young age and during aging


1 Institute of General Pathology and Pathophysiology, Moscow, Russia;

2 Zakusov Research Institute of Pharmacology, Moscow, Russia

Objective. To study the ability of mexidol to induce cerebral mitochondriogenesis in the brain of young and aging rats. Material and methods. Expression level of marker proteins of cerebral mitochondriogenesis was evaluated during treatment with mexidol (20, 40, 100 mg/kg; 20 days; intraperitoneally) in the cerebral cortex of young (3 month) and aging (6, 9, 12, and 15 month) outbred male rats, using the Western blot analysis. Results. It has been shown for the first time that the course injections of mexidol in doses of 40 and 100 mg/kg is accompanied by dose-dependent induction of the succinate receptor SUCNR1 and protein markers of mitochondrial biogenesis: transcription coactivator PGC-1α, transcription factors (NRF1, TFAM), catalytic subunits of respiratory enzymes (NDUV2, NDUV2,cytb, COX2) and ATP synthase (ATP5A) in the cerebral cortex of young and aging outbred male rats. Mexidol-dependent overexpression of subunits of mitochondrial enzymes and PGC-1α is observed only with the course of the drug. Conclusion. The results indicate the ability of mexidol to induce cerebral mitochondriogenesis and eliminate mitochondrial dysfunction in young and aging animals and, thus, exert an effect on one of the key pathogenetic links of the development of disorders in aging and neurodegenerative diseases.
Keywords: aging, mitochondrial dysfunction, mexidol, succinate receptor, cerebral mitochondriogenesis, transcriptional coactivator PGC-1α, respiratory enzyme subunits, rats, Western blot analysis.

Effect of mexidol on physical and mental performance under stressogenic conditions in experiment


FSBI «Zakusov Institute of Pharmacology», Moscow

Resume. The effect of Mexidol on physical performance of mice under the extreme conditions of the weight-loaded forced swim test and on the mental performance of rats under the conditions of a neurosis-like state caused by a functional disturbance of a defensive instrumental conditioned active avoidance reflex was studied. A single dose (50 and 100 mg/kg) or a subchronic regimen (100 mg/kg) of Mexidol administered intrapertoneally enhances the physical performance of mice similarly to mildronate (100 mg/kg). Mexidol improves the rate of operant conditioning, the preservation of the memory trace and its restoration after single or multiple instances of disruption of the conditioned active avoidance reflex, and its effect does not differ from the effect of the comparison drug piracetam (300 mg/kg).
Keywords: performance; learning; memory; functional disturbance.

Effect of mexidol on physical working efficiency and level of lactat in blood rats in conditions of light desynhronizes


Federal state budgetary institution «Siberian Federal science-clinical center of Federal medicobio-logical agency», Seversk, Russia; Siberian
State Medical University SSMU, Tomsk, Russia

Objective. To study an effect of mexidol on the performance of rats after light or dark deprivations in the swimming test with a load and to evaluate the state of glycolytic processes under these conditions. Material and methods. The experiment was carried out in the spring on 70 Wistar male rats. Three groups (30 animals) were in natural light conditions. One of them was not affected. The other two groups were subjected to exercise and 30 minutes before it either saline or mexidol was administered intramuscularly. Four other groups (40 animals) for 10 days were under conditions of dark or light deprivation prior to the presentation of physical activity and received either saline or mexidol before the test after deprivation was canceled. A forced swimming test with an additional load, which was presented to animals every day at 10—11 am for five days in a row, was used as a model of physical activity. The level of lactate was determined by colorimetric method. Results and conclusion. Mexidol increased the performance of rats in the swimming test, both under natural lighting conditions and with light desynchronization, contributed to the formation of cross adaptation to physical activity under natural lighting conditions and prolonged this state under conditions of light deprivation, did not change the content of lactate in the blood of rats after exercise in natural lighting conditions and dark deprivation and prevented its rise after light deprivation.

Keywords: mexidol, light and dark deprivation, working capacity, lactate.

Influence of mexidol and hemisuccinate 2-ethyl-6-methyl-3-hydroxypyridine on cerebral hemodynamics at hemorrhagic and ischemic damage of brain


1 V.V. Zakusov State Institute of Pharmacology, Russian Academy of Medical Sciences, Moscow, ul. Baltiiskaya 8, Moscow. 125315 Russia

2 I.M. Sechenov First Moscow State Medical University (Sechenov University), ul. Trubetskaya 8, Moscow, 119881 Russia

Comparative study of the effect of mexidol and hemisuccinate 2-ethyl-6-methyl-3-hydroxypyridine on the cerebral circulation of rats under conditions of hemorrhagic and ischemic brain lesions revealed significant differences in their cerebrovascular effects. Mexidol at a dose of 200 mg/kg i.v. better improves the local cerebral blood flow in modeling ischemia as compared to hemorrhagic brain damage. Hemisuccinate 2-ethyl-6-methyl-3-hydroxypyridine at a dose of 50 mg/kg better enhances the local blood supply to the cerebral cortex under conditions of hemorrhagic brain damage as compared to ischemic damage, since its cerebrovascular effect during cerebral ischemia occurs in a dose of 100 mg/kg. The mechanism of cerebrovascular anti-ischemic effect of 2-ethyl-6-methyl-3-hydroxypyridine hemisuccinate is mediated by GABAa receptors of the brain vessels, since bicuculline eliminates this effect.

Keywords: mexidol; hemisuccinate 2-ethyl-6-methyl-3-hydroxypyridine; bicuculline; cerebral circulation; hemorrhagic stroke model; global transient ischemia.

An effect of mexidol on the expression of the transcription factor Nrf2 in cerebral cortex in ischemia

Ryazan State Medical University, Ryazan, Russia.

Objective. To study an effect of the antioxidant and antihypoxant mexidol (ethylmethylhydroxypyridine succinate) on the transcription factor Nrf2 expression in neuronal nucleis of frontal cortex cells autor the common carotid artery unilateral occlusion. Material and methods. The study was performed on 64 male Wistar rats. The Nrf2 expression was determined immunohistochemically. Results. Single intraperitoneal mexidol (120 mg/kg b.w.) infusion and oral (100 mg/kg p.w. thrice a day for 14 days) administration of mexidol did not affect Nrf2 expression. Unilateral common carotid artery occlusion led to the increase in Nrf2 expression 4 h and 5 days after occlusion. Oral administration of mexidol in dose of 100 mg/kg b.w. thrice a day for 14 days before and after ischemia increased Nrf2 expression on the 4th h and on the 12th day in comparison with intact animals. Nrf2 expression was higher after 4 h and 12 days in comparison with the control occlusion group. Conclusion. Mexidol increases Nrf2 expression in the frontal cortex of rats not under normal conditions but in common carotid artery unilateral occlusion.

Keywords: mexidol, Nrf2, ethylmethylhydroxypyridine succinate, ischemia, occlusion, common carotid artery.

The study of the neuroprotective effect of mexidol on the cellular model of glutamate stress

Federal Research Center «Informatics and Cybernetics», RAS, Moscow, Russia; Scientific Center of Neurology, Moscow, Russia; Ivanovo State Medical Academy of the Ministry of Health of Russia, Ivanovo, Russia

Purpose of the study. Study of neuroprotective properties of mexidol on a cellular model of glutamate stress. Material and methods. Cytological studies were carried out under the conditions of the model of glutamate stress in the culture of granular neurons of the cerebellum. Results. The addition of mexidol to the cultural medium increased the survival of neurons by 8-10% after the addition of glutamate (p<.05). The effect of mexidol was more pronounced when applied at the stage of growing the culture of neurons (5 days), when the survival of the cells in conditions of glutamate stress increased by an average of 20%. The conclusion. The results of the study confirm the direct neuroprotective effect of mexidol in the culture of neurons under the conditions of the glutamate stress.

Keywords: cellular stress, excitotoxicity, glutamate, mexidol.