Regulation and Role of Hypoxia-Induced Factor 1α (HIF-1α) under Conditions of Endogenous Oxidative Stress In Vitro.

The effect of endogenous oxidative stress induced by γ-glutamyl cysteinesynthetase inhibitor D,L-buthionine sulfoximine (BSO) on the functioning of hypoxia-induced factor 1α (HIF-1α) was studied on Caco-2 cells. BSO was added for 24 h in concentrations of 5, 10, 50, 100, and 500 µM. It was shown that BSO in concentrations of 10, 50, and 100 µM induced endogenous oxidative stress and increased the content of HIF-1α; this effect was regulated through nuclear factor of erythroid origin 2 (Nrf2). Activation of HIF-1α had an independent protective effect, as evidenced by the decrease in cell viability after HIF-1α inhibition under these conditions. When the concentration of BSO was increased to 500 µM the content of HIF-1α did not change, and cell viability decreased.

Effect of Nitric Oxide on the Functioning of the P-Glycoprotein Transporter.

We studied the effect of nitric oxide (NO) on the functioning of P-glycoprotein transporter (Pgp) in Caco-2 cells. NO donor S-nitrosoglutathione (GSNO) was used in concentrations of 1, 10, 50, 100, and 500 µM; the duration of exposure was 24 h. The content of Pgp was analyzed by the Western blotting, activity of the transport protein was analyzed by the transport of its substrate fexofenadine. It was shown that GSNO in concentrations of 10 and 50 µM increased the content and activity of Pgp. Increasing the GSNO concentration to 500 µM led to the development of nitrosative stress and a decrease in the content and activity of the transporter protein.

Induction of Constitutive Androstane Receptor during the Development of Oxidative Stress.

We studied the effect of 3-, 24-, and 72-h exposure to H2O2 in concentrations of 0.1-100.0 µM on the level of constitutive androstane receptor in Caco-2 cells. It was shown that 3- and 24-h incubation with Н2О2 in all concentrations had no effect on the level of constitutive androstane receptors. Increasing the incubation time to 72 h led to an increase in the level of constitutive androstane receptor at H2O2 concentrations of 5, 10, and 50 µM and to a decrease at a concentration of 100 µM. Antioxidant glutathione (1 mM) in parallel to the prooxidant neutralized these changes.

[Effect of an antioxidant on vascular wall cell apoptosis markers after reconstructive operations]. / Vliianie antioksidanta na markery apoptoza kletok sosudistoi stenki posle rekonstruktivnykh operatsii.

AIM: This study was aimed at determining Bcl-2 and Bax proteins expression before and after reconstructive-repairing operations in patients with atherosclerosis obliterans of lower extremities and at assessing the effect of an antioxidant (vitamin E at a dose of 100 mg once daily for 1 month after surgery) on the dynamics of changes of Bcl-2 and Bax proteins in the postoperative period. PATIENTS AND METHODS: The study included a total of 60 patients with stage III-IV lower limb atherosclerosis obliterans. All patients underwent reconstructive-repairing operations on the arteries of the aortofemoral segment. After surgery the patients were divided into two groups. Group A included 30 patients who during 1 month received additionally to basic therapy vitamin E at a daily dose of 100 mg. Group B was composed of 30 patients receiving basic therapy alone according to the National guidelines of managing patients with peripheral artery disease. All patients before, on POD 1, and 1 month after surgery were subjected to venous blood test aimed at determining Bcl-2 and Bax apoptosis proteins expression by means of enzyme-linked immunosorbent assay. RESULTS: In patients of groups A and B, the baseline level of Bcl-2 protein (4.75 and 4.2 ng/ml, respectively) was comparable with that in apparently healthy volunteers (5.3 ng/ml). The baseline levels of Bax protein in patients of the operated groups (26.9 and 26.0 ng/ml, respectively) were increased compared with the values in healthy volunteers (16.5 ng/ml). On POD 1 there was increased expression of Bax protein in Group A and B patients to 39.4 and 30.2 ng/ml, respectively. One month after surgery, Group B patients demonstrated a decrease in the Bcl-2 values below the baseline level - 1.1 ng/ml (p=0.003), with the Bax level continuing to increase - 36 ng/ml (p=0.004). In turn, Group A patients after 1 month were found to have increased levels of the Bcl-2 protein - 5.75 ng/ml, with the Bax level returning to the baseline values - 27.4 ng/ml. CONCLUSION: In stage III and IV lower limb obliterating atherosclerosis, the level of the Bax proapoptoric protein was higher than that in healthy volunteers. On POD 1, there occurred increased expression of the pro-apoptotic protein Bax and activation of apoptosis markers. On the background of using vitamin E at a dose of 100 mg once daily for 1 month, there was a decrease in level of the Bax propapoptotic protein (p=0.003) and an increase in level of the anti-apoptotic Bcl-2 protein level (p=0.0007).

[The distribution of mexidol in the rat's brain and its subcellular fractions].

OBJECTIVE: To study the penetration of mexidol through the blood-brain barrier into different brain compartments and cell mitochondria. MATERIAL AND METHODS: The study was carried out on adult male Wistar rats using the drug mexidol ("Farmasoft" Russia). The penetration of mexidol into different compartments of the brain (the cortex, cerebellum, thalamus and medulla) and distribution between mitochondrial and cytoplasmic fractions of the cerebral cortex was studied. The concentration of mexidol in blood plasma and brain tissues was measured using HPLC. RESULTS AND CONCLUSION: Mexidol penetrated through the blood-brain barrier into brain compartments of rats with the maximal accumulation in the cortex. In the brain cortex cells, mexidol was identified in the cytoplasmic and mitochondrial fractions.

[Sex differences of P-glycoprotein functional activity and expression in rabbits].

The research consists in the investigation of the sex differences of P-glycoprotein functional activity and expression in Chinchilla rabbits. P-glycoprotein functional activity was assessed by the pharmacokinetics of its probe substrate--fexofenadine after its single oral administration. P-glycoprotein expression was investigated by immunohistochemistry method. It is shown that male's maximal concentration of fexofenadine, its areas under concentration-time curves, half-life and retention time were higher and its clearance was lower than female's. The efficient differences in pharmacokinetic parameters of fexofenadine confirm more intensive excretion and less intensive absorption in gastro-intestinal tract of fexofenadine. This data indicate that P-glycoprotein activity is more active in female than in male. Immunohistochemistry analysis shows that total liver and intestine P-glycoprotein expression is more intensive in females, than in males that correlates with its more active functioning.

[P-glycoprotein: structure, physiological role and molecular mechanisms of modulation functional activity].

In the review of literature the structure, localization and a physiological role of efflux biobiotics and xenobiotics transporter - P-glycoprotein - is characterized, molecular mechanisms of induction and inhibition of its functional activity are systematized.

[A comparative study of mexidol and mexiprim pharmacokinetic parameters]. / Sravnenie farmakokineticheskikh parametrov preparata meksidol s preparatom étilmetilgidroksipiridina suktsinat.

Objective. To compare pharmacokinetic parameters of mexidol (coated tablets, "Farmasoft") and mexiprim (tablets film-coated, "STADA CIS"). Material and methods. The study included 14 adult male Chinchilla rabbits. Concentration of 2-ethyl-6-methyl-3-hydroxypyridine succinate in the blood plasma of animals was analyzed using HPLC with UV detection. Results and conclusion. Mexidol as compared to mexiprim was more completely and rapidly absorbed from the gastrointestinal tract, it was confirmed by the higher value of maximal concentration of 2-ethyl-6-methyl-3-hydroxypyridine succinate and less maximal concentration time after mexidol administration. The drugs had similar excretion that was confirmed by the lack of significant differences in the values of total clearance, half-life, and the average retention time.

[Effect of mexidol on the development of the phenomenon of the neuronal excitotoxicity in vitro].

Effect of mexidol on the development of the phenomenon of the excitotoxic syndrome in vitro has been studied. Mexidol inhibits in vitro the development of glutamate-induced neurotoxicity, ascorbate-dependent (non-enzymatic) and NADPH2-dependent (enzymatic) iron-induced lipid peroxide oxidation, is able in high concentrations to bind superoxide anion-radical, significantly increases the activity of Se-dependent glutathione peroxidase, decreases the activity of induced NO-synthase and does not impact on the activity of glutathione-SH-transferase, catalase and neuronal NO-synthase. These effects underlie the antioxidant and antihypoxic action of the drug.