Beneficial effect of gaseous nitric oxide on the healing of skin wounds

Intermittent daily exposures (60 s) to NO-containing gas flow (NO dose of 500 ppm) generated by air-plasma unit "Plason" improves healing of skin wounds in rats. The gas flow treatment shortened the recovery time of both aseptic and purulent wounds (300 mm2 area) by nearly a third. The treatment allows to achieve a marked improvement in the histological, histochemical, and electron-microscopic characteristics of the affected tissue. The mechanism of this phenomenon was studied by spin trapping method. The NO status of the wound tissue was investigated with EPR by following the formation of paramagnetic mononitrosyl complexes with iron-diethyldithiocarbamate, or with the heme groups in hemoglobin or myoglobin. For the first 5 min after a gas treatment with the exposure of 60s, detectable NO levels in the affected tissue were slightly lowered with respect to untreated controls. At subsequent times, treated tissues showed the formation of large quantities of nitroso-iron complexes: At 30-40 min after gas exposure, their levels were nearly two orders of magnitude higher than soon after (15 s-5 min) the exposure. The data demonstrate that the accumulation of nitrosyl-iron complexes reflects a sharp rise in endogenous NO production inside the affected tissue. Paradoxically, the beneficial effect of gaseous NO treatment can be mediated by the formation of limited quantities of peroxynitrite due to the reaction between exogenous NO and superoxide anions generated in high amount in wound tissue. This peroxynitrite has a strong prooxidant effect and can activate various antioxidant systems which diminish the amount of superoxide anions in wound tissue. The reduced superoxide levels allow to increase the contents of endogenous NO in gas-treated tissues. Therefore, the beneficial action of the treatment is attributed to enhanced NO bioavailability.     

Effect of exogenous donors of nitric oxide and inhibitors of its enzymatic synthesis on experimental ischemic thrombosis in conjunctive veins of the rabbit eyes

The beneficial action of dinitrosyl iron complex with glutathione on conjunctive veins of eyes in rabbits with experimental thrombosis of conjunctive veins has been demonstrated. Aqueous solutions of dinitrosyl iron complexes were added subconjunctively at doses of 5.4-8.1 micromole per eye. The average duration of thrombosis by the action of dinitrosyl iron complex decreased from 6.4 days in control animals to 2 days. The addition of dinitrosyl iron complex resulted in blood flow recovery in occlusive vessels and prevented ischemia and necrosis of tissues. The enhancement of hemorrhagic activity induced by dinitrosyl iron complexes was abrogated with combined addition of the nonselective NO synthase inhibitor N-nitro-L-arginine. In contrast, S-nitrosoglutathione affected adversely the veins: the duration of thrombosis in experimental thrombosis of conjunctive veins increased to 7 days. Intensive hemorhage developed in the conjunctive. The formation of protein-bound dinitrosyl iron complexes was observed by the EPR method in eye tissues after the subconjunctive or parabulbar addition of dinitrosyl iron complex with glutathione. This was not the case when the complex was injected intravenously. It was shown that dinitrosyl iron complex with glutathione induces the blockade of pellet aggregation or strengthens the fibrinolytic activity of plasma of patients with eye vessel pathology. The beneficial action of dinitrosyl iron complexes on conjunctive veins was proposed to be due to the capacity of dinitrosyl iron complexes to donate NO primarily to its biological targets. The release of free NO molecules in large amounts is not characteristic for dinitrosyl iron complexes. This process is characteristic of S-nitrosoglutathione, which sharply increases the probability of the accumulation of peroxynitrite, which produces a toxic effect on cells and tissues.     

Dinitrosyl iron complexes with thiol ligands promote skin wound healing in animals

Dimeric dinitrosyl iron complexes (DNIC) with cysteine or glutathione as NO donors accelerated the healing of experimental skin wound in rats, as demonstrated by histological and histochemical examination. After two injections of an aqueous DNIC solution into the wound (total 5 μmol) on days 1 and 2 after surgery, the granulocyte volume in wound tissue on day 4 was 3–4 times greater than in the control. Higher DNIC doses provoked inflammation in the wound. Similar experiments with another NO donor S-nitrosoglutathione in equivalent amounts (10 μmol) adversely affected the wound. Addition of 2.5 μmol glutathione DNIC for 40 min produced EPR-detectable protein-bound DNIC (2.5 nmol) in wound tissue. Under the same conditions, 5 μmol S-nitrosoglutathione produced less than 10 pmol of protein-bound DNIC; an EPR-active nitrosyl hemoglobin complex was mainly formed (1.5–2.0 nmol) in this case. The beneficial effect of DNIC on the wound was suggested to be due to the delivery of NO to its targets without pronounced formation of cytotoxic peroxynitrite in wound tissue. In contrast, peroxynitrite could form upon administration of rapidly decomposed S-nitrosoglutathione, thereby aggravating the wound condition.     

Protein-bound dinitrosyl-iron complexes appearing in blood of rabbit added with a low-molecular dinitrosyl-iron complex: EPR studies.

The formation of protein-bound dinitrosyl-iron complexes (DNIC) in blood plasma and packed red cell fraction has been demonstrated by the EPR method in the experiments on rabbits which were i/v injected with the low-molecular DNIC with thiosulphate. This formation was ensured by transfer of Fe(+)(NO(+))(2) moieties from low-molecular DNIC onto serum albumin or hemoglobin molecules. Protein-bound DNICs appeared immediately after low-molecular DNIC injection followed with gradually decreasing their amounts. The complexes could be detected by EPR technique during more than two days. The addition of water-soluble NO scavenger, the iron complex with N-methyl-d-glucamine dithiocarbamate (MGD) resulted in decomposition of a part of protein-bound DNICs and in effective excretion of secondary products (mainly mononitrosyl-iron complexes with MGD) from the blood flow.     

Redox thiol status plays a central role in the mobilization and metabolism of nitric oxide in human red blood cells

We assessed the redox thiol status influence on nitric oxide (NO) metabolism and efflux in erythrocytes stimulated with acetylcholinesterase substrate (acetylcholine, ACh) and inhibitor (velnacrine maleate, VM). Erythrocyte suspensions from healthy donors were incubated with increasing concentrations of dithiothreitol (1-50 μM), in the presence and absence of acetylcholine/velnacrine (10 μM). Levels of NO, nitrite/nitrate, S-nitrosohemoglobin, peroxynitrite and S-nitrosoglutathione were determined by spectrofluorimetric and spectrophotometric methods.Dithiothreitol significantly mobilized NO toward nitrite/nitrate and S-nitrosoglutathione, and decreased the amount of NO efflux. Both ACh/VM induce changes on the levels of erythrocyte nitrite/nitrate dependent on the DTT concentration. Higher levels of peroxynitrite and S-nitrosoglutathione were seen with velnacrine in presence of DTT 1 and 50 μM.We concluded that dithiothreitol-induced activation of erythrocyte thiol status decreases NO efflux and allows greater intracellular NO mobilization onto different derivative molecules, both in the absence and presence of acetylcholinesterase substrate and inhibitor.     

Why does iron abrogate the cytotoxic effect of S-nitrosothiols on human and animal cultured cells?

It was found that dinitrosyl iron complexes (DNIC) with thiol-containing ligands (cysteine or glutathione) of concentrations up to 1 mM produce no cytotoxic effect on cultured cells from human milk gland carcinoma (MCF-7). The cytotoxic action on MCF-7 cells was produced by S-nitrosocysteine: at a concentration of 1 mM, it induced the death of 50% cells. A more stable S-nitrosothiol, S-nitrosoglutathione, did not produce any cytotoxic effect at the same concentration. It is assumed that the negative action of nitrosocysteine is due to its rapid degradation, which results in the accumulation of large amounts of free NO molecules followed by their oxidation by superoxide ions to peroxynitrite, an efficient inhibitor of metabolic processes. These processes seem to be not characteristic of the more stable S-nitrosoglutathione. The cytotoxic effect of nitrosocysteine was completlly abrogated by the addition of 0.2 mM ferrous citrate complex to the medium. When S-nitrosoglutathione NO (0.5 mM) or S-nitrosoglutathione (0.5 mM) + Fe(2+)-citrate (0.2 mM) were added to the medium, protein-bound dinitrosyl iron complexes formed with the involvement of endogenous or exogenous iron were detected in cells. The amount of the complexes in the presence of exogenous iron increased four times, reaching the value of 1.6 nmole/5 x 10(6) cells. Therefore, it was proposed that the blockade of the cytotoxic action of S-nitrosoglutathione by iron complexes is due to Cys-NO transformation of S-nitrosocysteine into dinitrosyl iron complexes. The high stability of these complexes ensures only a gradual accumulation of nitric oxide in cells.     

Effects of reactive species of oxygen and nitrogen on iron ion release from ferritin and synthesis of dinitrosyl iron complexes

Using EPR spectroscopy it was established that Fe ions released from ferritin under the action of glutathione and superoxide took part in the formation of dinitrosyl complexes of iron with glutathione (DNIC). The reaction between O2-. and NO resulted in the formation of peroxynitrite, which oxidized glutathione to the thiyl radical. In these conditions, DNIC did not inhibit the formation of thiyl radicals but effectively slowed down the oxidative destruction of beta-carotene by peroxynitrite and free radicals of lipids. In the presence of glutathione, the inversion of the antioxidant properties of DNIC into prooxidant ones took place. S-nitrosoglutathione prevented this inversion and suppressed the free-radical oxidation of beta-carotene induced by ferritin. It was proposed that the equilibrium between S-nitrosoglutathione, DNIC, "free Fe" ions and ferritin may determine the balance between prooxidant and antioxidant processes in living organisms.     

Formation of paramagnetic nitrosyl complexes of non heme iron in animals with participation of nitric oxide from exogenous and endogenous sources

It was found that thiosulfate has a stabilizing effect on exogenous and endogenous dinitrosyl-iron complexes in mice treated with bacterial lipopolysaccharide. It was assumed that thiosulfate protects dinitrosyl-iron complexes from the destructive influence of superoxide and peroxinitrite whose enhanced synthesis, together with the synthesis of nitric oxide, is initiated in mice by the lipopolysaccharide. For the first time, the formation of dinitrosyl-iron complexes was demonstrated, which occurs with the participation of nitric oxide generated enzymatically via the L-arginine-dependent pathway. The injection of exogenous dinitrosyl-iron complexes with thiosulfate, which, together with diethyldithiocarbamate, provide the formation of exogenous mononitrosyl iron-diethyldithiocarbamate complexes, made it possible to use the ABC method, which markedly enhances the efficiency of scavenging of endogenous nitric oxide in mice treated with lipopolysaccharides.     

Activation of soluble guanylate cyclase by NO donors--S-nitrosothiols, and dinitrosyl-iron complexes with thiol-containing ligands.

We studied the capability of dimeric forms of dinitrosyl-iron complexes and S-nitrosothiols to activate soluble guanylate cyclase (sGC) from human platelet cytosol. The dinitrosyl-iron complexes had the ligands glutathione (DNIC-GS) or N-acetylcysteine (DNIC-NAC). The S-nitrosothiols were S-nitrosoglutathione (GS-NO) or S-nitrosoacetylcysteine (SNAC). For both glutathione and N-acetylcysteine, the DNIC and S-nitrosothiol forms are equally effective activators of sGC. The activation mechanism is strongly affected by the presence of intrinsic metal ions. Pretreatment with the potent iron chelator, disodium salt of bathophenanthroline disulfonic acid (BPDS), suppressed sGC activation by GS-NO: the concentration of GS-NO producing maximal sGC activation was increased by two orders of magnitude. In contrast, activation by DNIC-GS is strongly enhanced by BPDS. When BPDS was added 10 min after supplementation of DNIC-GS or GS-NO at 4 degrees C, it exerted a similar effect on sGC activation by either NO donor: BPDS only enhanced the sGC stimulation at low concentrations of the NO donors. Our experiments demonstrated that both Fe(2+) and Cu(2+) ions contribute to the decomposition of GS-NO in the presence of ascorbate. The decomposition of GS-NO induced by Fe(2+) ions was accompanied by formation of DNIC. BPDS protected GS-NO against the destructive action of Fe(2+) but not Cu(2+) ions. Additionally, BPDS is a sufficiently strong chelator to remove the iron from DNIC-GS complexes. Based on our data, we propose that S-nitrosothiols activate sGC via a two-step iron-mediated process: In the first step, intrinsic Fe(2+) ions catalyze the formation of DNICs from S-nitrosothiols. In the secondary step, these newly formed DNICs act as the real NO donors responsible for sGC activation.     

Regulation of the functional and mechanical properties of platelet and red blood cells by nitric oxide donors

The effect of NO donors (sodium nitroprusside, S-nitrosoglutathione, dinitrosyl-iron complexes) on the functional and mechanical properties of human platelets and red blood cells has been investigated. It has been established by atomic force microscopy that NO donor-induced platelet disaggregation is accompanied by changes in the elastic properties of cells. It has been shown that, in the presence of NO donors, the detergent-induced hemolysis of red blood cells is delayed, and the elasticity modulus of these cells decreases. The results obtained indicate that NO donors regulate the structural and functional properties of platelets and red blood cells.     

Mechanical wounding induces a nitrosative stress by down-regulation of GSNO reductase and an increase in S-nitrosothiols in sunflower (Helianthus annuus) seedlings

Nitric oxide (NO) and related molecules such as peroxynitrite, S-nitrosoglutathione (GSNO), and nitrotyrosine, among others, are involved in physiological processes as well in the mechanisms of response to stress conditions. In sunflower seedlings exposed to five different adverse environmental conditions (low temperature, mechanical wounding, high light intensity, continuous light, and continuous darkness), key components of the metabolism of reactive nitrogen species (RNS) and reactive oxygen species (ROS), including the enzyme activities L-arginine-dependent nitric oxide synthase (NOS), S-nitrosogluthathione reductase (GSNOR), nitrate reductase (NR), catalase, and superoxide dismutase, the content of lipid hydroperoxide, hydrogen peroxide, S-nitrosothiols (SNOs), the cellular level of NO, GSNO, and GSNOR, and protein tyrosine nitration [nitrotyrosine (NO(2)-Tyr)] were analysed. Among the stress conditions studied, mechanical wounding was the only one that caused a down-regulation of NOS and GSNOR activities, which in turn provoked an accumulation of SNOs. The analyses of the cellular content of NO, GSNO, GSNOR, and NO(2)-Tyr by confocal laser scanning microscopy confirmed these biochemical data. Therefore, it is proposed that mechanical wounding triggers the accumulation of SNOs, specifically GSNO, due to a down-regulation of GSNOR activity, while NO(2)-Tyr increases. Consequently a process of nitrosative stress is induced in sunflower seedlings and SNOs constitute a new wound signal in plants.     

The mechanisms of S-nitrosothiol decomposition catalyzed by iron.

The mechanisms of S-nitrosothiol transformation into paramagnetic dinitrosyl iron complexes (DNICs) with thiol- or non-thiol ligands or mononitrosyl iron complex (MNICs) with N-methyl-D-glucamine dithiocarbamate catalyzed by iron(II) ions under anaerobic conditions were studied by monitoring EPR or optical features of the complexes and S-nitrosothiols. The kinetic investigations demonstrated the appearance of short-living paramagnetic mononitrosyl-iron complex with L-cysteine prior to the formation of stable dinitrosyl-iron complex with cysteine in the solution of iron(II)-citrate complex (50-100 microM), S-nitrosocysteine (400 microM), and L-cysteine (20 mM) in 100 mM Hepes buffer (pH 7.4). The addition of deoxyhemoglobin (100 microM) did not influence the process, which points to a direct interaction between S-nitrosocysteine and iron(II) ions to yield DNIC. The reaction of DNIC-cysteine formation is first- and second-order in iron and S-nitrosocysteine, respectively. The third-order rate constant is (1.0 +/- 0.2) x 10(5) M(-2) s(-1) (estimated from EPR results) or (2.0 +/- 0.1) x 10(4) M(-2) s(-1) (estimated by optical method). A similar process of DNIC-cysteine formation was observed in a solution of iron(II)-citrate complex, L-cysteine, and NO-proline (200 microM) as a NO* donor. The appearance of a less stable dinitrosyl-iron complex with phosphate was detected when solutions of iron(II)-citrate containing 100 mM phosphate buffer (pH 7.4) were mixed with S-nitrosocysteine or NO-proline. The rapid formation of DNIC with phosphate was followed by its decay. When the concentration of L-cysteine in solutions was reduced from 20 to 1 mM, the life-time of the DNIC-cysteine diminished notably; this was caused by consumption of L-cysteine in the process of DNIC-cysteine formation from S-nitrosocysteine and iron. Thus, L-cysteine is consumed. Formation of DNIC with glutathione was also observed in a solution of glutathione (20 mM), S-nitrosoglutathione (400 microM), and iron(II) complex (800 microM) in 100 mM Hepes buffer (pH 7.4), but the rate of formation was about 10 times slower than the formation of the DNIC-cysteine. The rate of MNIC-MGD formation from iron(II)-MGD complexes and S-nitrosocysteine was first-order in both reactants. The second-order rate constant for this reaction, estimated from EPR measurements, was 30 +/- 5 M(-1) s(-1). Rate constants of MNIC-MGD formation from iron(II)-MGD and the more stable S-nitrosoglutathione and S-nitroso-D,L-penicillamine were equal to 3.0 +/- 0.3 and 0.3 +/- 0.05 M(-1) s(-1), respectively. Thus, the concerted mechanism of DNIC and MNIC formation from S-nitrosothiols and iron(II) ions can be suggested to be predominant.     

The antitumor activity of the S-nitrosoglutathione and dinitrosyl iron complex with glutathione: Comparative studies

The antitumor activity of the binuclear form of dinitrosyl iron complexes with glutathione against Lewis lung carcinoma was found earlier with intraperitoneal administration of the complexes. This activity was also observed when this preparation was injected subcutaneously. The complex inhibited the tumor growth by 43% upon subcutaneous injection at a daily dose of 100 µM/kg (as calculated per one iron atom in the binuclear dinitrosyl iron complex) for 10 or 15 days. The effect was observed during the first 2 weeks after tumor transplantation. After this, the tumors began to grow at a rate that was equal to or even higher than that for the control animals. The mean survival time for the treated mice exceeded the control values by 30%. Binuclear dinitrosyl iron complexes were also effective against Ca-755 adenocarcinoma with intraperitoneal administration. In this case, however, the mean survival time for the treated animals only increased by 7%. It was also shown that S-nitrosoglutathione inhibited the growth of Lewis lung carcinoma and Ca-755 adenocarcinoma by 70 and 90%, respectively. However, in contrast to binuclear dinitrosyl iron complexes, the antitumor effect of S-nitrosoglutathione decreased with an increase in the daily dose of the compound from 200 to 400 µM/kg. The initial antitumor effect of binuclear dinitrosyl iron complexes and S-nitrosoglutathione is suggested to be due to NO that is released from both compounds. The subsequent suppression of the effect is caused by the activation of antinitrosative and antioxidant defense systems in tumors.     

Cellular non-heme iron content is a determinant of nitric oxide-mediated apoptosis, necrosis, and caspase inhibition

In this report, we tested the hypothesis that cellular content of non-heme iron determined whether cytotoxic levels of nitric oxide (NO) resulted in apoptosis versus necrosis. The consequences of NO exposure on cell viability were tested in RAW264.7 cells (a cell type with low non-heme iron levels) and hepatocytes (cells with high non-heme iron content). Whereas micromolar concentrations of the NO donor S-nitroso-N-acetyl-DL-penicillamine induced apoptosis in RAW264.7 cells, millimolar concentrations were required to induce necrosis in hepatocytes. Caspase-3 activation and cytochrome c release were evident in RAW264.7 cells, but only cytochrome c release was detectable in hepatocytes following high dose S-nitroso-N-acetyl-DL-penicillamine exposure. Pretreating RAW264.7 cells with FeSO(4) increased intracellular non-heme iron to levels similar to those measured in hepatocytes and delayed NO-induced cell death, which then occurred in the absence of caspase-3 activation. Iron loading was also associated with the formation of intracellular dinitrosyl-iron complexes (DNIC) upon NO exposure. Cytosolic preparations containing DNIC as well as pure preparations of DNIC suppressed caspase activity. These data suggest that non-heme iron content is a key factor in determining the consequence of NO on cell viability by regulating the chemical fate of NO.     

The potent vasodilating and guanylyl cyclase activating dinitrosyl-iron(II) complex is stored in a protein-bound form in vascular tissue and is released by thiols.

We studied the biological activity, stability and interaction of dinitrosyl-iron(II)-L-cysteine with vascular tissue. Dinitrosyl-iron(II)-L-cysteine was a potent activator of purified soluble guanylyl cyclase (EC50 10 nM with and 100 nM without superoxide dismutase) and relaxed noradrenaline-precontracted segments of endothelium-denuded rabbit femoral artery (EC50 10 nM superoxide dismutase). Pre-incubation (5 min; 310 K) of endothelium-denuded rabbit aortic segments with dinitrosyl-iron(II)-L-cysteine (0.036-3.6 mM) resulted in a concentration-dependent formation of a dinitrosyl-iron(II) complex with protein thiol groups, as detected by ESR spectroscopy. While the complex with proteins was stable for 2 h at 310 K, dinitrosyl-iron(II)-L-cysteine in aqueous solution (36-360 microM) decomposed completely within 15 min, as indicated by disappearance of its isotropic ESR signal at gav = 2.03 (293 K). Aortic segments pre-incubated with dinitrosyl-iron(II)-L-cysteine released a labile vasodilating and guanylyl cyclase activating factor. Perfusion of these segments with N-acetyl-L-cysteine resulted in the generation of a low molecular weight dinitrosyl-iron(II)-dithiolate from the dinitrosyl-iron(II) complex with proteins, as revealed by the shape change of the ESR signal at 293 K. The low molecular weight dinitrosyl-iron(II)-dithiolate accounted for an enhanced guanylyl cyclase activation and vasodilation induced by the aortic effluent. We conclude that nitric oxide (NO) produced by, or acting on vascular cells can be stabilized and stored as a dinitrosyl-iron(II) complex with protein thiols, and can be released from cells in the form of a low molecular weight dinitrosyl-iron(II)-dithiolate by intra- and extracellular thiols.     

Detection of nitrosyl-iron complexes by proton-electron-double-resonance imaging.

The nitrogen monoxide radical (NO*) forms paramagnetic mono- and dinitrosyl-iron complexes in biologic tissues. To establish a noninvasive technique for in vivo NO* imaging, we evaluated the suitability of these complexes as magnetic resonance (MR) contrast agents, making use of the ability of the unpaired electrons of the complexes to enter into dynamic nuclear polarization with water protons and hence produce enhancement on images generated by the technique of proton-electron-double-resonance imaging (PEDRI). Phantom solutions of synthetic nitrosyl-iron complexes (NICs) altered the signal intensity of PEDRI images. The dinitrosyl-iron complex (DNIC) with serum albumin induced a significantly larger signal alteration than the mononitrosyl-iron complex (MNIC) with dithiocarbamate. Exposure of rat liver to sodium nitroprusside (SNP) by ex vivo and in situ perfusion induced a composite X-band electron spin resonance (ESR) spectrum of the isolated liver characteristic of a MNIC and DNIC. On storage of the tissue, the MNIC signal disappeared and the DNIC signal intensity increased. Correspondingly, in cross-sectional PEDRI images taken at room temperature, the SNP-exposed livers initially exhibited a weak signal that strongly increased with time. In conclusion, NICs can be detected using PEDRI and could be exploited for in vivo NO* imaging.     

Interaction of Oxoferrylmyoglobin and Dinitrosyl-Iron Complexes

It is shown that dinitrosyl-iron complexes (DNIC) with glutathione can reduce oxoferrylmyoglobin forming on interaction of tert-butyl hydroperoxide and metmyoglobin. A rapid decrease in the DNIC concentration was observed under the conditions of production of tert-butyl free radicals; however, destruction of DNIC in the presence of oxoferrylmyoglobin alone was negligible. It is demonstrated that DNIC reduces oxoferrylmyoglobin more than an order more efficiently than S-nitrosoglutathione and glutathione. DNIC also inhibits formation of the thiyl radicals of glutathione in a medium containing metmyoglobin and tert-butyl hydroperoxide. A mechanism of the antioxidant action of DNIC based on regeneration of the nitrosyl complexes from the products of their interaction with oxoferrylheme is proposed.     

Antioxidant and prooxidant action of nitric oxide donors and metabolites

It has been shown that various nitric oxide donors and metabolites have similar effects on lipid peroxidation in rat myocardium homogenate. The formation of malondialdehyde, a secondary product of lipid peroxidation, was inhibited in a dose-dependent manner by PAPA/NONO (a synthetic nitric oxide donor), S-nitrosoglutathione, nitrite, and nitroxyl anion. The inhibition of lipid peroxidation was provided most efficiently by the administration of dinitrosyl-iron complexes with dextran and PAPA/NONO. S-nitrosoglutathione also inhibited the destruction of coenzymes Q9 and Q10 during free radical oxidation of myocardium homogenate. Low-molecular-weight dinitrosyl iron complexes with cysteine also promoted lipid peroxidation, which is probably due to iron release during the destruction dinitrosyl iron complexes. It is likely that the antioxidant action of nitric oxide derivatives is related to the reduction of ferry forms of hemoproteins and interaction of nitric oxide with lipid radicals.     

Study of dinitrosyl-iron complexes pharmacokinetics and accumulation in depot in rat organs

Protein-bound dinitrosyl-iron complexes (DNIC) in rat whole blood and organs were studied after intravenous injection of this substance with glutathione ligand (DNIC-GH). The effect of DNIC-GH injection on NO level (including NO physiological forms) in hydrophobic areas of rat tissues was also studied in normal physiological blood circulation condition. It has been shown, that after DNIC-GH injection the concentration of protein-bound DNICs in rat whole blood and organs rapidly reached maximum values, and then gradually decreased, that pointed to decomposition of DNIC molecules, coupled with NO release. At the beginning of the experiment the rates of DNIC decay in rat heart and lung were substantially higher, as compared with those in liver and kidney. By spin trappping it has been demonstrated that DNIC-GH, as a source of NO physiological forms (including S-nitrosothiols), in normal physiological blood circulation influence heart more selectively, as compared with the other organs.