Nitric Oxide Synthase Isoforms Research Articles

Immunomodulatory effect of sulfated galactofucan from marine macroalga Turbinaria conoides

Sulfated polysaccharides are effective immunostimulating agents by activating several intracellular signaling pathways. A sulfated (1 → 3)/(1 → 4)-linked galactofucan TCP-3 with promising immunomodulatory effects was purified from a marine macroalga Turbinaria conoides. The immune-enhancing potential of TCP-3 (100–400 mg/kg BW) was evaluated on cyclophosphamide-induced immunosuppressed animals by increasing bone marrow cellularity (10–13 cells/femur/mL x 106), α-esterase activity (1200–1700 number of positive cells/4000 BMC), interferon-γ (1.31–1.49 pg/mL), interleukin-2 (3.49–3.99 pg/mL) secretion, and WBC count (> 3000 cells/cu mm). The proliferation of lymphocytes for in vitro and in vivo conditions was enhanced by administering TCP-3 besides regulating the secretion of pro-inflammatory cytokines (interleukin-6/1β/12, tumor necrosis factor-α, transforming growth factor-β), and an inducible isoform of nitric oxide synthase. A promising reduction of viral copy formation was observed by administering TCP-3 (< 2 × 107 number) on SARS CoV-2 (delta variant) induced Vero cells in comparison with the infected group (> 5 × 107 number).

Effects of prenatal hypoxia-ischemia on male rat periaqueductal gray matter: Hyperalgesia, astrogliosis and nitrergic system impairment.

Prenatal hypoxic-ischemic insult (HI) may lead to a variety of neurological consequences that may persist throughout adulthood. In the most severe cases, HI is known to increase pain sensitivity which profoundly impacts quality of life. Periaqueductal gray matter (PAG) is a relevant region of the descending pain pathway and its function may be modulated by a complex network that includes nitrergic neurons and glial response, among other factors. Astrocytes, central players in pain modulation, are known to respond to HI by inducing hyperplasia, hypertrophy and increasing the number of their processes and the staining of glial fibrillary acidic protein (GFAP). In this work we investigated the effects of prenatal HI on touch and pain sensitivity, besides the distribution of the neuronal isoform of Nitric Oxide Synthase (nNOS) and GFAP in the PAG of young and adult male rats. At 18 days of gestation, rats had their uterine arteries clamped for 45min (HI group). SHAM-operated animals were also generated (SHAM group). At post-natal day 30 (P30) or 90 (P90), the offspring was submitted to the behavioral tests of Von Frey and formalin or histological processing to perform immunohistochemistry for nNOS and GFAP. Although there was no significant difference between the groups concerning touch sensitivity, we observed an increase in pain sensitivity in HI P30 and HI P90. The number of nNOS+cells was reduced in HI adult animals in dlPAG and vlPAG. GFAP immunostaining was increased in HI P90 in dlPAG and dmPAG. Our results demonstrated for the first time an increase in pain sensitivity as a consequence of prenatal HI in an animal model. It reinforces the relevance of this model to mimic the effects of prenatal HI, as hyperalgesia.

Influence of NF-κB on the development of oxidative-nitrosative stress in the liver of rats under conditions of chronic alcohol intoxication

Alcohol-related liver disease is the most common cause of liver disease worldwide. The purpose of this work is the establishment of the influence of the transcription factor κB on the development of oxidative-nitrosative stress in the liver of rats under conditions of chronic alcohol intoxication. The experiments were performed on 24 male Wistar rats weighing 180-220 g. The animals were divided into 4 groups of 6 animals: control; animals, which were administered NF-κB inhibitor, namely ammonium pyrrolidinedithio­carbamate (PDTC) at a dose of 76 mg/kg 3 times a week; animals, on which we simulated alcoholic hepatitis and group of combination of alcoholic hepatitis and NF-κB inhibitor. We determined in rat liver homogenate the following biochemical parameters: the activi­ty of NO synthase isoforms, superoxide dismutase and catalase activity, the concentration of malonic dialdehyde, the concentration of peroxynitrite, nitrites and nitrosothiols, concentration of sulfide anion and superoxide anion radical production. Chronic alcohol intoxication led to increased production of reactive oxygen and nitrogen species on the background of decreased antioxidant activity, thus intensifying lipid peroxidation in the liver. Blockade of the transcription factor κB during chronic alcohol intoxication despite an increase in antioxidant activity and decrease of reactive oxygen and nitrogen species production did not ameliorate oxidative damage to the liver. Blockade of activation of nuclear transcription factor κB in rat liver by PDTC reduced the risk of oxidative damage to hepatocytes, but did not reduce the risk of developing nitrosative damage to hepatocytes. Keywords: chronic alcohol intoxication, NF-κB, oxidative-nitrosative stress, PDTC, rat liver

β-cell–selective inhibition of DNA damage response signaling by nitric oxide is associated with an attenuation in glucose uptake

Nitric oxide (NO) plays a dual role in regulating DNA damage response (DDR) signaling in pancreatic β-cells. As a genotoxic agent, NO activates two types of DDR signaling; however, when produced at micromolar levels by the inducible isoform of NO synthase, NO inhibits DDR signaling and DDR-induced apoptosis in a β-cell-selective manner. DDR signaling inhibition by NO correlates with mitochondrial oxidative metabolism inhibition and decreases in ATP and NAD+. Unlike most cell types, β-cells do not compensate for impaired mitochondrial oxidation by increasing glycolytic flux, and this metabolic inflexibility leads to a decrease in ATP and NAD+. Here, we used multiple analytical approaches to determine changes in intermediary metabolites in β-cells and non-β-cells treated with NO or complex I inhibitor rotenone. In addition to ATP and NAD+, glycolytic and tricarboxylic acid cycle intermediates as well as NADPH are significantly decreased in β-cells treated with NO or rotenone. Consistent with glucose-6-phosphate residing at the metabolic branchpoint for glycolysis and the pentose phosphate pathway (NADPH), we show that mitochondrial oxidation inhibitors limit glucose uptake in a β-cell-selective manner. Our findings indicate that the β-cell-selective inhibition of DDR signaling by NO is associated with a decrease in ATP to levels that fall significantly below the KM for ATP of glucokinase (glucose uptake) and suggest that this action places the β-cell in a state of suspended animation where it is metabolically inert until NO is removed, and metabolic function can be restored.

The opposite effect of convulsant drugs on neuronal and endothelial nitric oxide synthase - A possible explanation for the dual proconvulsive/anticonvulsive action of nitric oxide.

Nitric oxide (NO) participates in processes such as endothelium-dependent vasodilation and neurotransmission/neuromodulation. The role of NO in epilepsy is controversial, attributing it to anticonvulsant but also proconvulsant properties. Clarification of this dual effect of NO might lead to the development of new antiepileptic drugs. Previous results in our laboratory indicated that this contradictory role of NO in seizures could depend on the nitric oxide synthase (NOS) isoform involved, which could play opposite roles in epileptogenesis, one of them being proconvulsant but the other anticonvulsant. The effect of convulsant drugs on neuronal NO (nNO) and endothelial NO (eNO) levels was investigated. Considering the distribution of neuronal and endothelial NOS in neurons and astrocytes, resp., primary cultures of neurons and astrocytes were used as a study model. The effects of convulsant drugs pentylenetetrazole, thiosemicarbazide, 4-aminopyridine and bicuculline on NO levels were studied, using a spectrophotometric method. Their effects on NO levels in neurons and astrocytes depend on the concentration and time of treatment. These convulsant drugs caused an increase in nNO, but a decrease in eNO was proportional to the duration of treatment in both cases. Apparently, nNO possesses convulsant properties mediated by its effect on the glutamatergic and GABAergic systems, probably through GABAA receptors. Anticonvulsant properties of eNO may be the consequence of its effect on endothelial vasodilation and its capability to induce angiogenesis. Described effects last as seizures do. Considering the limitations of these kinds of studies and the unexplored influence of inducible NO, further investigations are required.

Effect of Carotid Body Denervation on Systemic Endothelial Function in a Diabetic Animal Model.

Endothelial dysfunction is an essential intermediary for development of cardiovascular diseases associated with diabetes and hypertension (HT). The carotid body (CB) dysfunction contributes to dysmetabolic states, and the resection of carotid sinus nerve (CSN) prevents and reverts dysmetabolism and HT. Herein, we investigated if CSN denervation ameliorates systemic endothelial dysfunction in an animal model of type 2 diabetes mellitus (T2DM).We used Wistar male rats submitted to HFHSu diet during 25weeks and the correspondent age-matched controls fed with a standard diet. CSN resection was performed in half of the groups after 14weeks of diet. In vivo insulin sensitivity, glucose tolerance and blood pressure, ex vivo aortic artery contraction and relaxation and nitric oxide (NO) levels in plasma and aorta, aorta nitric oxide synthase (NOS) isoforms, and PGF2αR levels were evaluated.We demonstrated that, alongside to dysmetabolism and HT reversion, CSN resection restores endothelial function in the aorta and decreases the NO levels in plasma and aorta at the same time that restores normal levels of iNOS in aorta without changing eNOS or PGF2αR levels.These results suggest that the modulation of CB activity can be important for the treatment of HT and endothelial dysfunction related with T2DM.

The Comparison of the Influence of Bisphenol A (BPA) and Its Analogue Bisphenol S (BPS) on the Enteric Nervous System of the Distal Colon in Mice.

Bisphenol A (BPA), commonly used as a plasticizer in various branches of industry has a strong negative effect on living organisms. Therefore, more and more often it is replaced in production of plastics by other substances. One of them is bisphenol S (BPS). This study for the first time compares the impact of BPA and BPS on the enteric neurons using double immunofluorescence technique. It has been shown that both BPA and BPS affect the number of enteric neurons containing substance P (SP), galanin (GAL), vasoactive intestinal polypeptide (VIP), neuronal isoform of nitric oxide synthase (nNOS-a marker of nitrergic neurons) and/or vesicular acetylcholine transporter (VAChT- a marker of cholinergic neurons). The changes noted under the impact of both bisphenols are similar and consisted of an increase in the number of enteric neurons immunoreactive to all neuronal factors studied. The impact of BPS on some populations of neurons was stronger than that noted under the influence of BPA. The obtained results clearly show that BPS (similarly to BPA) administered for long time is not neutral for the enteric neurons even in relatively low doses and may be more potent than BPA for certain neuronal populations.

Disrupting the nNOS/NOS1AP interaction in the medial prefrontal cortex impairs social recognition and spatial working memory in mice

The neuronal isoform of nitric oxide synthase (nNOS) and its interacting protein NOS1AP have been linked to several mental disorders including schizophrenia and depression. An increase in the interaction between nNOS and NOS1AP in the frontal cortex has been suggested to contribute to the emergence of these disorders. Here we aimed to uncover whether disruption of their interactions in the frontal cortex leads to mental disorder endophenotypes. Targeting the medial prefrontal cortex (mPFC), we stereotaxically injected wild-type C57BL/6J mice with recombinant adeno-associated virus (rAAV) expressing either full-length NOS1AP, the nNOS binding region of NOS1AP (i.e. NOS1AP396-503), or the nNOS amino-terminus (i.e. nNOS1-133), which was shown to disrupt the interaction of endogenous nNOS with PSD-95. We tested these mice in a comprehensive behavioural battery, assessing different endophenotypes related to mental disorders. We found no differences in anxiety-related and exploratory behaviours. Likewise, social interaction was comparable in all groups. However, social recognition was impaired in NOS1AP and NOS1AP396-503 mice. These mice, as well as mice overexpressing nNOS1-133 also displayed impaired spatial working memory (SWM) capacity, while spatial reference memory (SRM) remained intact. Finally, mice overexpressing NOS1AP and nNOS1-133, but not NOS1AP396-503, failed to habituate to the startling pulses in an acoustic startle response (ASR) paradigm, though we found no difference in overall startle intensity or prepulse inhibition (PPI) of the ASR. Our findings indicate a distinct role of NOS1AP/nNOS/PSD-95 interactions in the mPFC to contribute to specific endophenotypic changes observed in different mental disorders.

Pharmacological applications of nitric oxide-releasing biomaterials in human skin

Nitric oxide (NO) is an important endogenous molecule that plays several roles in biological systems. NO is synthesized in human skin by three isoforms of nitric oxide synthase (NOS) and, depending on the produced NO concentration, it can actuate in wound healing, dermal vasodilation, or skin defense against different pathogens, for example. Besides being endogenously produced, NO-based pharmacological formulations have been developed for dermatological applications targeting diverse pathologies such as bacterial infection, wound healing, leishmaniasis, and even esthetic issues such as acne and skin aging. Recent strategies focus mainly on developing smart NO-releasing nanomaterials/biomaterials, as they enable a sustained and targeted NO release, promoting an improved therapeutic effect. This review aims to overview and discuss the main mechanisms of NO in human skin, the recent progress in the field of dermatological formulations containing NO, and their application in several skin diseases, highlighting promising advances and future perspectives in the field.

Neuronal nitric oxide synthase positive neurons in the human corpus callosum: a possible link with the callosal blood-oxygen-level dependent (BOLD) effect.

Brain functions have been investigated in the past decades via the blood-oxygen-level dependent (BOLD) effect using functional magnetic resonance imaging. One hypothesis explaining the BOLD effect involves the Nitric Oxide (NO) gaseous neurotransmitter, possibly released also by cells in the corpus callosum (CC). The eventual presence of NO releasing neurons and/or glial cells in the CC can be assessed by immunohistochemistry. Serial sections both from paraffin-embedded and frozen samples of CC obtained from adult human brains autopsy were studied with immunohistochemistry and immunofluorescence analysis, using an antibody against the neuronal isoform of Nitric Oxide Synthase (nNOS), the enzyme synthetizing the NO. The staining revealed the presence of many nNOS-immunopositive cells in the CC, shown to be neurons with immunofluorescence. Neuronal NOS-positive neurons presented different morphologies, were more numerous 4mm apart from the midline, and displayed a peak in the body of the CC. In some cases, they were located at the upper boundary of the CC, more densely packed in the proximity of the callosal arterioles. The significant presence of nNOS-immunopositive neurons within the commissure suggests their probable role in the CC neurovascular regulation in the adult brain and could explain the BOLD effect detected in human CC.

The neuronal isoform of nitric oxide synthase (nNOS) serves as the main inducer of PKA oxidation in the heart

The neuronal isoform of nitric oxide synthase (nNOS) serves as the main inducer of PKA oxidation in the heart

Absence of Nitrergic Modulation of Starling Response in Haemoglobin-Less Antarctic Fish Chionodraco hamatus

The Frank-Starling response is an intrinsic heart property that is particularly evident in the fish heart because piscine cardiomyocytes are extremely sensitive to stretch. Several mechanisms and compounds influence the Frank-Starling response, including the free radical nitric oxide produced by nitric oxide synthases in the vascular endothelium and cardiomyocytes of all vertebrates. Besides its role in scavenging nitric oxide, hemoglobin may act as a source and transporter. In this context, the hemoglobin-less Antarctic teleost Chionodraco hamatus (icefish) represents a unique opportunity to investigate the involvement of nitric oxide in the Frank-Starling response. Using an isolated perfused heart preparation, weverified a basal nitrergic tone that is not implicated in the Frank-Starling response. In addition, by comparing nitric oxide synthases expression and activation in C. hamatus and the red-blooded Antarctic teleost Trematomus bernacchii, we found the endothelial isoform of nitric oxide synthase (the primary generator of nitric oxide during shear stress) to be less expressed and activated in the former.

Abstract 9578: Chronic Phosphodiesterase Type 5 Inhibition by Sildenafil Causes Regression of Heart Failure: Insights into Molecular and Cellular Mechanisms

Background: Sildenafil (SIL), a selective inhibitor of PDE5 has been shown to exert profound beneficial effects in heart failure (HF). However, whether and by what mechanisms SIL can stop the progression of HF, or maybe even reverse the clinical route remain unknown. We tested the hypothesis that chronic SIL would improve intrinsic myocyte function and [Ca 2+ ] i regulation and reverse HF-induced detrimental alterations on cardiac SERCA2a, β-adrenergic receptors (AR) and nitric oxide synthase (NOS) isoforms, thus playing a salutary role in HF. Methods: We evaluated LV and myocyte function and the protein levels of myocyte β 1 - and β 3 - AR, SR Ca 2+ -ATPase (SERCA2a), phospholamban (PLB), and 3 NOS in 3 groups of male rats (8/group) for a period of 3 months (M): 1) HF , 3 M after receiving isoproterenol (ISO) (170 mg/kg sq for 2 days); 2) HF/SIL , 2 M after ISO, then SIL (70 μg/kg/day sq via mini pump) was initiated and given for 1 M; and 3) Controls . Results: Versus C, ISO-treated rats progressed to severe HF at 3 M with significantly reduced LV contractility (E ES , 0.7 vs 1.1 mmHg/μl), and slowed LV relaxation. LV myocyte contraction (dL/dt max , 77 vs 136 μm/sec), relaxation (dR/dt max , 62 vs 104 μm/sec) and [Ca 2+ ] iT (0.15 vs 0.24) were significantly decreased accompanied by a diminished myocyte inotropic response to ISO (10 -8 M) superfusion. These abnormalities were associated with concomitant significant decreases in myocyte protein levels of β 1 -AR (0.23 vs 0.64), SERCA2a (0.46 vs 0.80), PLB Ser16 /PLB ratio, and eNOS (0.28 vs 0.46), but increased protein levels of β 3 -AR (0.23 vs 0.10) and iNOS (0.18 vs 0.08). Chronic SIL treatment prevented HF-caused reduced E ES (1.3 mmHg/μl) and EF (62%) and retained normal dL/dt max (131μm/s), dR/dt max (106 μm/s), and [Ca 2+ ] iT (0.24), and restored normal myocyte contractile response to ISO stimulation. With SIL, protein levels of myocyte β 1 - and β 3 -AR, SERCA2a were normalized to control values, but eNOS was significantly elevated (0.77). Conclusions: Chronic SIL prevents HF-caused downregulation of cardiac β 1 -AR and reverses contrast changes between iNOS and β 3 -AR with SERCA2a and eNOS expression, restores normal myocyte function, [Ca 2+ ] iT , and β-adrenergic reserve, and leads to regression of LV dysfunction in a rat model of progressive HF.

Roles of Ferredoxin-NADP+ Oxidoreductase and Flavodoxin in NAD(P)H-Dependent Electron Transfer Systems.

Distinct isoforms of FAD-containing ferredoxin-NADP+ oxidoreductase (FNR) and ferredoxin (Fd) are involved in photosynthetic and non-photosynthetic electron transfer systems. The FNR (FAD)-Fd [2Fe-2S] redox pair complex switches between one- and two-electron transfer reactions in steps involving FAD semiquinone intermediates. In cyanobacteria and some algae, one-electron carrier Fd serves as a substitute for low-potential FMN-containing flavodoxin (Fld) during growth under low-iron conditions. This complex evolves into the covalent FNR (FAD)-Fld (FMN) pair, which participates in a wide variety of NAD(P)H-dependent metabolic pathways as an electron donor, including bacterial sulfite reductase, cytochrome P450 BM3, plant or mammalian cytochrome P450 reductase and nitric oxide synthase isoforms. These electron transfer systems share the conserved Ser-Glu/Asp pair in the active site of the FAD module. In addition to physiological electron acceptors, the NAD(P)H-dependent diflavin reductase family catalyzes a one-electron reduction of artificial electron acceptors such as quinone-containing anticancer drugs. Conversely, NAD(P)H: quinone oxidoreductase (NQO1), which shares a Fld-like active site, functions as a typical two-electron transfer antioxidant enzyme, and the NQO1 and UDP-glucuronosyltransfease/sulfotransferase pairs function as an antioxidant detoxification system. In this review, the roles of the plant FNR-Fd and FNR-Fld complex pairs were compared to those of the diflavin reductase (FAD-FMN) family. In the final section, evolutionary aspects of NAD(P)H-dependent multi-domain electron transfer systems are discussed.

Nitro-Oxidative Stress and Mitochondrial Dysfunction in Human Cell Lines Exposed to the Environmental Contaminants PFOA and BPA.

Bisphenol A (BPA) and perfluorooctanoic acid (PFOA) are synthetic compounds widely utilized in industrial activities devoted to the production of daily life plastic, metal products, and packaging from which they are able to migrate to food and water. Due to their persistence in the environment, living organisms are chronically exposed to these pollutants. BPA and PFOA have adverse effects on tissues and organs. The aim of this study was to identify the molecular targets and biochemical mechanisms involved in their toxicity. HepG2 and HaCaT cells were treated with BPA or PFOA, and the trypan blue exclusion test and 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay were performed to define the conditions for subsequent investigations. We conducted quantitative PCR and western blot analysis to evaluate the expression of proteins involved in nitric oxide (NO) signaling. Cell-based assays were carried out to evaluate reactive oxygen species (ROS) production, nitrite/nitrate (NOx) accumulation, 3-nitrotyrosine (3-NT) formation, and mitochondrial membrane potential (MMP) determination in treated cells. HepG2 and HaCaT cells incubated for 24 h with subtoxic concentrations of BPA or PFOA (50 and 10 μM, respectively) exhibited altered mRNA and protein expression levels of NO synthase isoforms, manganese superoxide dismutase, and cytochrome c. Treatment with PFOA led to activation of inducible NO synthase (NOS), a marker of nitrosative stress, accompanied by the increased production of ROS, NOx, and 3-NT and alterations of the MMP compared to controls. The results of this study indicate the major involvement of the NO signaling axis in the persistent alteration of cell redox homeostasis and mitochondrial dysfunction induced by BPA and PFOA, highlighting the specific role of PFOA in NOS regulation and induction of nitro-oxidative stress.

Pharmacological correction of the sequelae of acute alcohol-induced myocardial damage with new derivatives of neuroactive amino acids coupled with the blockade of the neuronal NO synthase isoform

Introduction: Acute alcohol intoxication (AAI) induces a number of myocardial disorders, which result in mitochon­drial dysfunction in cardiomyocytes, oxidative stress, and decreased cardiac contractility. Nitric oxide produced by the nNOS is one of the major modulators of cardiac activity. New derivatives of GABA (RSPU-260 compound) and glu­tamate (glufimet) can be potentially regarded as such agents as the interaction between the NO system and the GABA and glutamatergic systems has been proved.&#x0D; Materials and methods: All the studies were performed on female white Wistar rats, aged 10 months, whose weight was 280–320g AAI intoxication was modeled of 32% ethanol (gavage, 4g/kg).&#x0D; Results and discussion: Glufimet and the RSPU-260 compound caused a significant improvement in myocardial contractility, increased oxygen consumption in the V3 state according to Chance, raised the respiratory control ratio and decreased the intensity of LPO intensity. Their effectiveness exceeded that of mildronate, their comparator. nNOS inhibition resulted in a pronounced aggravation of oxidative stress implicated in MDA accumulation in cardiac mito­chondria and decreased activity of SOD; myocardial contractility and mitochondrial function indicators did not show a significant difference from the control group. The compounds under study coupled with nNOS inhibition had a car­dioprotective effect.&#x0D; Conclusion: Glufimet and the RSPU-260 compound, derivatives of neuroactive amino acids, have a pronounced cardioprotective effect, restrict LPO processes, enhance SOD activity, improve the mitochondrial respiratory function after acute alcohol intoxication when coupled with neuronal NO-synthase inhibition, the expression of which persists after AAI.&#x0D; Graphical abstract:

18F]NOS PET Brain Imaging Suggests Elevated Neuroinflammation in Idiopathic Parkinson's Disease.

Neuroinflammation is implicated as a key pathologic mechanism in many neurodegenerative diseases and is thought to be mediated in large part by microglia, native phagocytic immune cells of the CNS. Abnormal aggregation of the protein α-synuclein after phagocytosis by microglia is one possible neuropathophysiological mechanism driving Parkinson’s disease (PD). We conducted a human pilot study to evaluate the feasibility of targeting the inducible isoform of nitric oxide synthase using the [18F]NOS radiotracer to measure neuroinflammation in idiopathic PD. Ten adults consisting of 6 PD patients and 4 healthy controls (HC) underwent one hour of dynamic [18F]NOS positron emission tomography (PET) brain imaging with arterial blood sampling. We observed increased [18F]NOS whole brain distribution volume (VT) in PD patients compared to age-matched healthy controls (p < 0.008) via a 1-tissue compartment (TC) model. The rate constant K1 for transport from blood into tissue did not differ between groups (p = 0.72). These findings suggest elevated oxidative stress, a surrogate marker of inflammation, is present in early-stage idiopathic PD and indicate that [18F]NOS PET imaging is a promising, non-invasive method to measure neuroinflammation.

EFFECT OF CURCUMIN ON THE DEVELOPMENT OF OXIDATIVE-NITROSATIVE STRESS IN THE LIVER TISSUES OF RATS EXPOSED TO MODELED METABOLIC SYNDROME UNDER ROUND-THE-CLOCK LIGHTING

The aim of this study is to evaluate the effect of curcumin, a natural polyphenol, on indicators of oxidative-nitrosative stress in the liver of rats exposed to modeled metabolic syndrome (MS) under 24-hour lighting. The experiments were performed on 21 Wistar male white rats weighing 215-255 g. The animals were divided into 3 groups of 7 animals in each. The animals of the 1st group (control I) were kept on a standard vivarium diet and an ordered alternation of light / dark periods. The rats of the 2nd group were used for modeling diet-induced MS (a 2-month carbohydrate-lipid diet including 20% aqueous fructose solution for drinking and appropriate food) under the 24-hour lighting (control II). The rats of the 3rd group received curcumin (Sigma-Aldrich, Inc., USA) intragastrically through a gavage in a dose of 200 mg/kg daily during the 24-hour lighting exposure. We investigated the liver homogenate of rats to assess the rate of generation of the superoxide anion radical (•О), the activity of total NO synthase (NOS), its constitutive and inducible isoforms (cNOS, iNOS), and the content of peroxynitrites of alkali and alkaline earth metals. The administration of curcumin under the experimental conditions significantly suppresses the •О production in liver tissues by microsomal monooxygenases and NOS by 40.1%, by the mitochondrial respiratory chain by 34.4%, and by leukocyte NADPH oxidase by 32.1%; the activity of NOS and iNOS by 39.0% and 41.6%, the concentration of peroxynitrites of alkaline and alkaline earth metals by 23.8 compared to the values in the 2nd group. The activity of cNOS under these conditions was 2.79 times higher than the respective results in the II control, and the coupling index of this isoenzyme was 4.3 times higher. The main conclusion that can be drawn is that the administration of curcumin in the rat model of MS under the round-the-clock lighting significantly reduces the signs of oxidative-nitrosative stress in the liver tissues.

EFFECT OF TRANSCRIPTION FACTOR MODULATORS ON OXIDATIVE-NITROSATIVE STRESS INDICATORS IN TISSUES OF THE SMALL INTESTINE OF RATS AFTER LAPARATOMY UNDER LIPOPOLYSACCHARIDE-INDUCED SYSTEMIC INFLAMMATORY RESPONSE

This study is devoted to investigating the effect of NF-κB and Nrf2 transcription factor modulators on oxidative-nitrosative stress indicators in the tissues of the small intestine of rats after abdominal surgical trauma (laparotomy) under lipopolysaccharide (LPS)-induced systemic inflammatory response (SIR). The study was performed on 35 Wister white male rats weighing 220-250 g, divided into 5 groups: the 1st (control) group included "sham-operated" animals; the 2nd group involved rats, who underwent laparotomy following the LPS-induced SIR modelling; the animals of the 3rd, 4th and 5th groups subjected to laparotomy following LPS-induced SIR and then for 7 days received ammonium pyrrolidine dithiocarbamate, an NF-κB activation inhibitor, in a dose of 76 mg/kg intraperitoneally, dimethyl fumarate, an Nrf2 inducer, in a dose of 15 mg/kg in 10% dimethyl sulfoxide solution, and a water-soluble form of quercetin in a dose of 100 mg/kg that is 10 mg/kg in terms of quercetin, respectively. The measurements were carried out in 7 days after the “sham” surgical operation and laparotomy. It has been found out that the use of ammonium pyrrolidine dithiocarbamate, dimethyl fumarate, and water-soluble form of quercetin in case of the combined effects of surgical trauma (laparotomy) and LPS S. typhi significantly restrains the production of superoxide anion radical by various sources (microsomes and constitutive isoforms of NO-synthase, leukocyte NADPH-oxidase), total and inducible NO-synthase activity, formation of peroxynitrite in the tissues of the small intestine of rats. The study has also demonstrated the ability of dimethylfumarate, unlike ammonium pyrrolidine dithiocarbamate and quercetin, to improve the constitutive synthesis of nitric oxide under experimental conditions.

Inhibitory effects of Indonesian temu kunci (Boesenbergia rotunda) rhizome extract on nitric oxide synthase production and on the kidneys of Wistar rats

Nitric oxide synthases (NOSs) are enzymes that function by generating nitric oxide (NO) from its substrate, L‑arginine, in human tissues. There are three known isoforms of NOS, eNOS (endothelial NOS), nNOS (neuronal NOS), and iNOS (inducible NOS). iNOS is released in response to inflammation. The human iNOS inhibitor, S‑ethylisothiourea (SEITU), has been found to attach to a Glu377 residue within the active‑site cavity of the enzyme. The discovery of iNOS inhibitors is always challenging. <em>Boesenbergia rotunda</em> (<em>B. rotunda</em>) has been reported to reduce inflammation in an animal model. The present study examined the inhibitory effects of <em>B. rotunda</em> rhizome ethanolic extract (BRE) on iNOS using the fluorometric method and investigated the histopathological effects of higher concentrations of BRE (1,000, 2,000 and 4,000 mg/kg body weight) on the kidneys of male Wistar rats. Molecular docking simulation of quercetin and kaempferol towards iNOS was also performed. The phytochemical screening of BRE indicated the presence of polyphenolics, flavonoids, triterpenoids, and saponins. The <em>in vitro</em> experiment confirmed that BRE reduced NO production with a half‑maximal inhibitory concentration value of 79.06 µg/ml. Both quercetin and kaempferol interacted with Glu377 by building hydrogen bonds. Furthermore, the animal experiment resulted in no mortality and no marked morphological changes in the rat kidneys at all concentrations, indicating the safety of BRE as regards this organ. Taken together, BRE may be further developed as a safe anti‑inflammatory drug candidate.