Administration Of Aminoguanidine Research Articles

Influence of a Nitric Oxide Synthase Inhibitor on the Anxiolytic, Stimulating, and Analgesic Effects of Long-Term Perinatal Caffeine Exposure in Rats.

We studied the effect of inducible NO synthase (iNOS) inhibitor aminoguanidine on the behavioral effects of chronic perinatal caffeine exposure. Administration of caffeine in the prenatal and early postnatal periods led to the development of anxiolytic, stimulating, and analgesic effects. Administration of aminoguanidine attenuated the anxiolytic and stimulating effects and potentiated the analgesic effect of perinatal administration of caffeine. Chronic perinatal administration of caffeine leads to significant changes in the level of anxiety, motor activity, and pain sensitivity, and inhibition of iNOS has a pronounced multidirectional effect on these effects.

Advanced glycation end products impair coronary artery BK channels via AMPK/Akt/FBXO32 signaling pathway.

Background: Advanced glycation end products (AGEs) impair vascular physiology in Diabetes mellitus (DM). However, the underlying mechanisms remain unclear. Vascular large conductance calcium-activated potassium (BK) channels play important roles in coronary arterial function.Purpose: Our study aimed to investigate the regulatory role of AGEs in BK channels.Research Design: Using gavage of vehicle (V, normal saline) or aminoguanidine (A) for 8 weeks, normal and diabetic rats were divided into four groups: C+V group, DM+V group, C+A group, and DM+A group.Study Sample: Coronary arteries from different groups of rats and human coronary smooth muscle cells were used in this study.Data Collection and Analysis: Data were presented as mean ± SEM (standard error of mean). Student's t-test was used to compare data between two groups. One-way ANOVA with post-hoc LSD analysis was used to compare data between multiple groups.Results: Compared to the C+V group, vascular contraction induced by iberiotoxin (IBTX), a BK channel inhibitor, was impaired, and BK channel densities decreased in the DM+V group. However, aminoguanidine administration reduced the impairment. Protein expression of BK-β1, phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK), and protein kinase B (PKB or Akt) were down-regulated, while F-box protein 32 (FBXO32) expression increased in the DM+V group and in high glucose (HG) cultured human coronary smooth muscle cells. Treatment with aminoguanidine in vitro and in vivo could reverse the above protein expression. The effect of aminoguanidine on the improvement of BK channel function by inhibiting the generation of AGEs was reversed by adding MK2206 (Akt inhibitor) or Compound C (AMPK inhibitor) in HG conditions in vitro.Conclusions: AGEs aggravate BK channel dysfunction via the AMPK/Akt/FBXO32 signaling pathway.

Nitric oxide and salt resistance in Dahl rats: no role of inducible NO synthase.

Inducible NO synthase (NOS II) was proposed to play an important role in salt resistance of Dahl salt-resistant (SR/Jr) rats. Its chronic inhibition by specific inhibitors was accompanied by blood pressure (BP) elevation in animals subjected to high salt intake. The aim of our study was to evaluate 1) whether such inhibitors affect BP and/or its particular components (sympathetic tone and NO-dependent vasodilation) only under the conditions of high salt intake, and 2) whether similar BP effects are elicited after systemic or intracerebroventricular (icv) application of these inhibitors. Wistar rats fed Altromin diet (0.45 % NaCl) and SR/Jr rats fed either a low-salt (LS, 0.3 % NaCl) or a high-salt (HS, 4 % NaCl) diet were studied. Aminoguanidine (AMG) and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT) were used as NOS II inhibitors. BP and its responses to acute blockade of renin-angiotensin system (captopril), sympathetic nervous system (pentolinium) and NO synthase (L-NAME) were measured in conscious cannulated rats. There were no significant changes of BP or its components in either Wistar rats or SR/Jr rats subjected to chronic inhibition of NOS II by peroral aminoguanidine administration (50 mg/kg/day for 4 weeks). This was true for SR/Jr rats fed either LS or HS diets. Furthermore, we have studied BP effects of chronic icv administration of both NOS II inhibitors in SR/Jr rats fed HS diet, but we failed to find any BP changes elicited by such treatment. In conclusion, inducible NO synthase does not participate in the resistance of SR/Jr rats to hypertensive effects of excess salt intake.

Impact of nitric oxide synthesis modulators on the state of humoral immune system in experimental antiphospholipid syndrome

Background: Antiphospholipid syndrome is an autoimmune disease of multiple venous and/or arterial thrombosis and/or pregnancy loss. Oxidative stress only enhances the body’s immune response. In pathological conditions, the formation of nitric oxide is disrupted, which can be manifested by vasoconstriction, increased coagulation, and endothelial dysfunction. Objective: The aim of the research was to study the level of immunoglobulins and circulating immune complexes (CICs) in experimental antiphospholipid syndrome and its correction with L-arginine and aminoguanidine. Materials and methods: Antiphospholipid syndrome was modeled on white female BALB/c mice. L-arginine (25 mg/kg) and aminoguanidine (10 mg/kg) were used for its correction. The content of immunoglobulins and CICs was studied. Results: It was established that the level of immunoglobulins (Ig) and circulating immune complexes increased in the group of animals with antiphospholipid syndrome compare to the control. The levels of IgA and CICs decreased significantly, and the levels of IgM and IgG did not change in the mice with antiphospholipid syndrome and L-arginine correction. In cases of aminoguanidine administration, decreased IgM and IgG levels and no significant decrease in IgA and CICs was evidenced compare to the animals with antiphospholipid syndrome. In cases of using a combination of L-arginine and aminoguanidine agents, only IgM did not change, all other parameters decreased compare to the animals with APS. Conclusion: The parameters of the humoral immunity in female mice with experimental antiphospholipid syndrome increase. The level of immunoglobulins and circulating immune complexes decrease depending on the chosen correction agents or their complex administration. Thus, L-arginine and aminoguanidine has a positive effect on various immunity responses by decreasing the negative impact of pathobiochemical alterations.

Intrarenal arterial administration of human umbilical cord-derived mesenchymal stem cells effectively preserved the residual renal function of diabetic kidney disease in rat

BackgroundThis experimental study was designed as a preclinical study for testing the hypothesis that intrarenal arterial (IRA) transfusion of human umbilical cord-derived mesenchymal stem cells (HUCDMSCs) therapy preserved the residual renal function of diabetic kidney disease (DKD) in rat [induction by 5/6 nephrectomy of left kidney and right nephrectomy, followed by intraperitoneal administration of aminoguanidine (180 mg/kg) and streptozotocin (30 mg/kg)].MethodsAnimals (n = 24) were categorized into group 1 (sham-operated control), group 2 (DKD), group 3 [DKD + HUCDMSCs (2.1 × 105/IRA injection at day 28 after CKD induction)] and group 4 [(DKD + HUCDMSCs (6.3 × 105/IRA injection)].ResultsBy day 60 after DKD induction, the kidneys were harvested and the result showed that the creatinine level, ratio of urine protein/urine creatinine and kidney injury score were lowest in group 1, highest in group 2 and significantly lower in group 4 than in group 3 (all p < 0.0001). The protein expressions of apoptotic (cleaved caspase-3/cleaved PARP/mitochondrial Bax), fibrotic (TGF-ß/p-Smad3), autophagic (ratio of LC3B-II/LC3B-I, Atg5/Beclin-1), oxidative stress (NOX-1/NOX-2/oxidized protein/p22phox), mitochondrial/DNA-damaged (cytosolic-cytochrome-C/DRP1/γ-H2AX) and inflammatory (MMP-9/TNF-α/p-NF-κB) biomarkers exhibited an identical pattern, whereas the protein expressions of angiogenesis factors (CD31/vWF/vascularity) exhibited an opposite pattern of creatinine level among the groups (all p < 0.0001). Histopathological findings demonstrated the renal tubular-damaged (KIM-1)/kidney fibrosis area/oxidative stress (8-OHdG + cells) expressed an identical pattern, whereas the podocyte components (ZO-1/synaptopodin/podocin) exhibited an opposite pattern of creatinine level among the groups (all p < 0.0001). No tumorigenesis or immune rejection event was identified.ConclusionIRA injection of xenogeneic MSCs was safe and effectively protected the residual renal function and architectural integrity in DKD rat.

Effect of Nitric Oxide Synthase Inhibitor on the Learning and Spatial Memory in Rats Subjected to Long-Term Perinatal Administration of Caffeine.

We studied the effect of inducible nitric oxide synthase inhibitor aminoguanidine on learning and spatial memory in rats exposed to long-term administration to caffeine during the prenatal and early postnatal periods. The rats perinatally receiving caffeine demonstrated high learning ability in the Morris water maze. At the same time, the ability to remember the location of the hidden platform in the trial probe in these rats was reduced in comparison with that of the control group rats perinatally receiving water. Administration of aminoguanidine to rats under conditions of perinatal exposure to caffeine significantly improved the parameters of spatial learning and memory. Thus, inhibition of inducible nitric oxide synthase has a beneficial effect on the cognitive functions in offspring perinatally receiving caffeine.

ЭФФЕКТЫ ИЗОЛИРОВАННОГО И СОЧЕТАННОГО ВВЕДЕНИЯ L-АРГИНИНА И АМИНОГУАНИДИНА ПРИ ОСТРОМ ЭКСПЕРИМЕНТАЛЬНОМ ПЕРИТОНИТЕ

Objectives. To study the effects of isolated and combined administration of L-arginine and aminoguanidine in acute experimental peritonitis. Material and methods. Experiments were conducted on white male rats (n=185), divided into 5equal series, which were injected intraperitoneally, 0,6ml/100g: the 1st series (control) - 0.9%NaCl, the 2nd (experimental peritonitis, EP) - the 5th series - 15% fecal suspension, with intramuscular injection to rats of the 3rd series with: substrate of NO-synthase (NOS) - L-arginine, L-Arg (300mg/kg), 4thseries - inhibitor of inducible NOS - aminoguanidine, AG (15 mg/kg), the 5th series - L-Arg and AG in analogous doses. The signs of intoxication syndrome, changes in leukocyte differential count and peritoneal fluid, the severity of prooxidant-antioxidant imbalance, lesions of vascular endothelium and structural changes in the peritoneum were studied. Results. The research of the EP course in rats with combined administration of L-Arg and AG revealed in the presence of more significant corrective effect, in comparison with the results in EP with their isolated use, showing up in the increase of motor activity and muscular strength, normalization of breathing and thermoregulation, decrease in the severity of leukocytosis and nuclear shift of the leukogram to the left, increase in the phagocytic activity, decline in the concentration of nitrite/nitrates and malondialdehyde, increased level of reduced glutathione, decrease in the quantity of circulating endothelial cells in blood and structural disorders in peritoneum. Conclusions. The most pronounced corrective effect of combined administration of the NOS-substrate, L-Arg, and the inhibitor of its inducible isoform, AG, in rats with EP may result from the suppression of excessive NO production by AG, as well as the maintenance of the constitutive NOS-activity and various metabolic pathways in the course of L-Arg administration.

Methylglyoxal Scavengers Attenuate Angiogenesis Dysfunction Induced by Methylglyoxal and Oxygen-Glucose Deprivation.

Cerebral endothelial cells play an essential role in brain angiogenesis, and their function has been found to be impaired in diabetes. Methylglyoxal (MG) is a highly reactive dicarbonyl metabolite of glucose formed mainly during glycolysis, and its levels can be elevated in hyperglycemic conditions. MG is a potent precursor of AGEs (advanced glycation end-products). In this study, we investigated if MG can induce angiogenesis dysfunction and whether MG scavengers can ameliorate angiogenesis dysfunction induced by MG. Here, we used cultured human brain microvascular endothelial cells (HBMECs) treated with MG and oxygen-glucose deprivation (OGD) to mimic diabetic stroke in vitro. We also used the MG challenged chicken embryo chorioallantoic membrane (CAM) to study angiogenesis in vivo. Interestingly, administration of MG significantly impaired cell proliferation, cell migration, and tube formation and decreased protein expression of angiogenesis-related factors, which was rescued by three different MG scavengers, glyoxalase 1 (GLO1), aminoguanidine (AG), and N-acetyl cysteine (NAC). In cultured CAM, MG exposure significantly reduced angiogenesis and the angiogenesis-related dysfunction could be attenuated by pretreatment with AG or NAC. Treatment of cultured HBMECs with MG plus OGD increased cellular apoptosis significantly, which could be prevented by exposure to GLO1, AG, or NAC. We also noted that administration of MG increased cellular oxidative stress as measured by reactive oxygen species (ROS) generation, enhanced AGE accumulation, and receptor for advanced glycation end-product (RAGE) expression in the cultured HBMECs, which were partially reversed by GLO1, AG, or NAC. Taken together, our findings demonstrated that GLO1, AG, or NAC administration can ameliorate MG-induced angiogenesis dysfunction, and this can be mainly attributed to attenuated ROS production, reduced cellular apoptosis, and increased levels of angiogenic factors. Overall, this study suggested that GLO1, AG, or NAC may be promising candidate compounds for the treatment of angiogenesis dysfunction caused by hyperglycemia in diabetic ischemic stroke.

Attenuation of hyperglycemia and amadori products by aminoguanidine in alloxan-diabetic rabbits occurs via enhancement in antioxidant defenses and control of stress.

The micro- and macro-complications in diabetes mellitus (DM) mainly arise from the damage induced by Amadori and advanced glycation end products, as well as the released free radicals. The primary goal of DM treatment is to reduce the risk of micro- and macro-complications. In this study, we looked at the efficacy of aminoguanidine (AG) to prevent the production of early glycation products in alloxan-diabetic rabbits. Type1 DM was induced in rabbits by a single intravenous injection of alloxan (90 mg/kg body weight). Another group of rabbits was pre-treated with AG (100 mg/kg body weight) prior to alloxan injection; this was followed by weekly treatment with 100 mg/kg of AG for eight weeks. Glucose, insulin, and early glycation products (HbA1C and fructosamine) were measured in control, diabetic and AG treated diabetic rabbits. The effects of hyperglycemia on superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx), reduced glutathione (rGSH), nitric oxide, lipid peroxides, and protein carbonyl were investigated. Alloxan-diabetic rabbits had lower levels of SOD, CAT, Gpx, and rGSH than control rabbits. Nitric oxide levels were considerably greater. AG administration restored the activities of SOD, CAT, Gpx enzymes up to 70–80% and ameliorated the nitric oxide production. HbA1c and fructosamine levels were considerably lower in AG-treated diabetic rabbits. The observed control of hyperglycemia and amadori adducts in alloxan-diabetic rabbits by AG may be attributed to decrease of stress and restoration of antioxidant defenses.

Sex-specific endothelial dysfunction induced by high-cholesterol diet in rats: The role of protein tyrosine kinase and nitric oxide

Background and aimsAtherosclerosis is a chronic process playing a crucial role in the pathogenesis of cardiovascular disease. Sex-specific differences in the incidence of atherosclerosis indicate that estrogen has a protective effect on the cardiovascular disease. However, the role of sex on endothelium responses in animal models of high cholesterol (HC) diet-induced atherosclerosis has not been fully investigated. This study was aimed to investigate vascular responses in HC-fed rats. Methods and resultsMale and female Sprague rats (12-week-old) were treated with either a standard diet (n = 12 of each sex) or an HC enriched diet (n = 12 of each sex) containing 2% cholesterol for 24 weeks. HC treated animals (both sexes) showed increased levels of total cholesterol, LDL-cholesterol, triglyceride and blood pressure (BP) compared to control rats. While the BP of control rats (both sexes) was increased following aminoguanidine administration (AG, 100 mg/kg i.p.), it was not changed in HC animals (both sexes). The hypotensive effect of acetylcholine was significantly impaired in male HC-treated rats. In vitro experiments demonstrated that aortic rings from HC group (both sexes) had an increased contractile response to phenylephrine and a decreased vasodilatory response to acetylcholine. The vasorelaxant effect of acetylcholine in HC rats (only male) was improved by applying 10−5 M genistein (tyrosine kinase inhibitor) or AG. ConclusionHC diet alters endothelium function through Nitric oxide (NO) and tyrosine kinase pathways in male rats.

The Expression and Function of Nitric Oxide Synthase Enzyme in Atorvastatin Effects on Morphine-Induced Dependence in Mice

Background: Atorvastatin exerts neuroprotective effects on the treatment of central nervous system disorders. Morphine analgesic tolerance and dependence remain as major concerns in medicine. Nitric oxide (NO) pathway mediates the development of opioid analgesic tolerance and dependence, as well as atorvastatin neuroprotection. Objectives: The present study aimed to assess the possible involvement of the NO/cGMP pathway in the process of the effects of atorvastatin on morphine physical dependence. Methods: Dependence was induced by repetitive injection of morphine sulfate. Naloxone was injected at the dose of 4 mg/kg on the last day of the experiment to assess withdrawal signs. Animals received atorvastatin (1, 5, 10, and 20 mg/kg, orally). Nitric oxide synthase (NOS) inhibitors and ODQ were injected before protective dose of atorvastatin. The gene expression of NOS isoforms was evaluated by real-time PCR. Thereafter, the hippocampal levels of cGMP and nitrite were measured. Results: Treatment with atorvastatin 10 mg/kg significantly attenuated naloxone-induced withdrawal behaviours. The administration of L-NAME, aminoguanidine, and ODQ before atorvastatin enhanced its effects. The treatment with atorvastatin significantly decreased the nitrite and cGMP levels as well as NOS gene expression in the hippocampus of dependent animals. Conclusions: It can be concluded that atorvastatin, possibly, through inducible NOS, could alleviate morphine dependence and withdrawal signs.

Effect of L-arginine and aminoguanidine on the cytokine profile in obstetric antiphospholipid syndrome

Antiphospholipid syndrome (APS) is one of the autoimmune causes of miscarriage in pregnancy. We researched the influence of L-arginine (25 mg/kg), the precursor of nitric oxide synthesis, and aminoguanidine, the inhibitor of inducible NO-synthase (10 mg/kg) on the concentration of IL-1β, IL-6, TNF-α, IL-4, IL-10 in serum of BALB/c mice on the 18th day of pregnancy in cases of APS. In the serum of the pregnant mice with APS, an increase in the concentration of proinflammatory cytokines (IL-1β, IL-6, TNF-α) and a decrease in the concentration of anti-inflammatory cytokines (IL-4 and IL-10) was evidenced, relative to those of the pregnant animals without APS. With the use of L-arginine, a decrease in the concentration of IL-1β, IL-6, TNF-α and an increase in the concentration of IL-4 and IL-10 was established, compared with the indicators of the pregnant mice with APS. The introduction of aminoguanidine, the selective inhibitor of iNOS, did not cause any changes in IL-1β, IL-6 and IL-10 compared with the group of animals with APS. However, a decrease in TNF-α concentration and an increase in IL-4 concentration were proved in this series compared with the group of pregnant animals with APS. Combined administration of L-arginine and aminoguanidine caused a decrease in the concentration of IL-1β, IL-6, TNF-α and an increase in the concentration of IL-4 and IL-10, compared with the indicators of the animals with APS. Thus, the combined administration of L-arginine and aminoguanidine to the pregnant mice with APS contributes to the rebalancing of proinflammatory and anti-inflammatory cytokines in the serum more than their individual use.

Content of GFAP in the Brain of BALB/C Mice with the Antiphospholipid Syndrome: Effects of L-Arginine and Aminoguanidine

We investigated the influence of the nitric oxide precursor L-arginine and selective inhibitor of inducible NOS aminoguanidine on the content of glial fibrillary acidic protein (GFAP) in the cerebellum and cerebral hemispheres of BALB/c mice with the experimental antiphospholipid syndrome (APS). In the APS, the total amount of GFAP and amount of its component GFAP 49–37 kDa in the cerebellum were 280 and 640%, as compared with the control, while the respective figures in the cerebral cortex were 118% and 155%. Injections of L-arginine led to a further increase in the GFAP content in the cerebellum of animals with the APS. Administration of aminoguanidine alone and of aminoguanidine together with L-arginine provided decreases in the GFAP content in the cerebellum of APS mice. Aminoguanidine also reduced the GFAP content in the cerebral hemispheres in APS animals. The increased GFAP content in the cerebellum and cerebral hemispheres in mice with the APS is indicative of the development of reactive astrogliosis. Changes in the NO synthesis due to introduction of its modulators significantly affect the GFAP content in the above brain regions in animals with the APS. These facts indirectly confirm the role of NO in the regulation of the GFAP expression in astrocytes under conditions of this pathology. The presence of GFAP 49–37 kDa (mainly in the cerebellum) in BALB/c mice with APS appears to be a sign of proteolytic degradation of GFAP, suggesting alterations in the astrocyte cytoskeleton (intermediate filaments) in the respective brain regions.

Genotoxic and anti-proliferative effects of aminoguanidine on gamma-irradiated MCF-7 breast cancer cells.

The intracellular production of nitric oxide is studied as a relevant phenomenon in exposure to ionizing radiation. There is evidence of local nitric oxide production in solid tumours. Its effects were observed on the relationship between their presence with tumor progression, linked to the emergence of potential genotoxic or cytotoxic damage, or loss of proliferative capacities of tumour cells. The study evaluated the effects of the administration of aminoguanidine, a selective inhibitor of an isoform of nitric oxide synthase on the frequency of genotoxic damage, loss of clonogenic potential, induction of cytotoxicity and nitrite production after exposure to ionizing radiation in radiotherapeutic doses. Human breast tumor (MCF7) cells were treated with aminoguanidine (1 or 2 mM) and irradiated by gamma radiation at doses between 0.5 and 8Gy. The study used a well stablished technique with some modifications for evaluation of genotoxic damage by frequency of micronuclei in binucleated cells. In cultures treated with 1 mM, we observed increased cytotoxicity and genotoxicity, and reduction of the clonogenic potential of the colonies. Alternatively, 2 mM aminoguanidine produced the opposite effect, apparently protecting cultures from the effects of exposures. The experiments suggested that the administration of aminoguanidine may reduce the in vitro radiossensitivity of tumors due to the increase of the frequency of genotoxic damage.

Inhibition of nitric oxide synthase activity and chemokine (CXCL12) supplementation can improve hematopoietic reconstitution in mice lethally irradiated by 60Co gamma radiation

Reduction of nitric oxide (NO) production is related to increased survival in some models of infection and ionizing radiation (IR) exposure. The work used lethally irradiated (60Co, 8Gy) C57Bl6j mice, treated or not with aminoguanidine (AG), an inhibitor of an isoform of nitric oxide synthase (iNOS). Also tested iNOS-/- knockout mice and a distinct group treated intraperitoneally with synthetic CXCL12, a homing chemokine related to hematopoietic reconstitution after IR exposures. Aminoguanidine treatment lead to an overshoot of proliferation of hematopoietic CD34+ cells in bone marrows (2nd day after IR) and spleens (2nd to 4th day after IR) of irradiated mice, showing a compensative response of these organs against deleterious effects of radiation. CXCL12 mRNA production was increased in spleens of AG-treated mice at 2nd day after IR, but not in other periods neither in bone marrows. CXCL12 administration did not alter CD34+ counts but seemed to keep circulating platelet counts in levels comparable to controls. Thus, CXCL12 and AG administration could help on bone marrow repopulation after critically exposed individuals.

Inhibition of Advanced Glycation End Products Formation Attenuates Cardiac Electrical and Mechanical Remodeling and Vulnerability to Tachyarrhythmias in Diabetic Rats

Diabetic patients with cardiomyopathy show a higher incidence of arrhythmias and sudden death. Chronic hyperglycemia induces the formation of advanced glycation end products (AGEs), which contribute to the pathogenesis of diabetic cardiomyopathy. This study investigated whether inhibition of AGEs formation by aminoguanidine (AG) could prevent cardiac electromechanical and arrhythmogenic remodeling in diabetes mellitus. Streptozotocin-induced diabetic rats received AG (100 mg/kg daily, i.p.) or vehicle (normal saline, i.p.) for 5 weeks. The rats underwent hemodynamic recording to evaluate cardiac function, and heart preparations were used to determine the electrical, mechanical, and biochemical functions. In vitro high glucose-induced AGEs formation, reactive oxygen species (ROS) generation, and action potential changes were examined in HL-1 atrial cells. AG treatment improved the diabetes-induced depression in left ventricular pressure and the relaxation rate, and normalized the prolongation of QTc intervals in anesthetized rats. AG reduced the vulnerabilities to atrial and ventricular tachyarrhythmias in perfused diabetic hearts. AG normalized the prolonged action potential duration in diabetic atrial and ventricular muscles, which was correlated with the restoration of both transient outward (I to) and steady-state outward (I SS) K+ current densities in cardiomyocytes. The abnormal kinetics of Ca2+ transients and contraction were reversed in cardiomyocytes from AG-treated diabetic rats, along with parallel preservation of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2a) expression. Furthermore, ex vivo and in vitro studies showed AG attenuated AGEs and ROS formation. Thus, long-term administration of AG ameliorated cardiac electromechanical remodeling and arrhythmogenicity in diabetic rats and may present an effective strategy for the prevention of diabetes-associated arrhythmias.

Aminoguanidine reverses cognitive deficits and activation of cAMP/CREB/BDNF pathway in mouse hippocampus after traumatic brain injury (TBI)

ABSTRACTPrimary Objective: We aim to study the effects of chronic aminoguanidine (AG) administration on learning and memory impairment after TBI and explore the potential mechanism involved in this process.Research Design: Male C57BL/6J mice were divided into 6 groups: Control, TBI + Veh, TBI+ AG (50, 100, 200 and 400 mg/kg, i.p.).Methods and Procedures: Then, we measured cyclicadenosine 3ʹ, 5ʹ-monophosphate (cAMP) content, phosphorylated form of cAMP-response element binding protein (p-CREB) level, iNOS, brain-derived neurotrophic factor (BDNF) and postsynaptic density-93/95 (PSD-93/95) expression in hippocampus. The learning and memory abilities were assessed using Morris water maze and step-down test.Main Outcomes and Results: The results demonstrate that TBI induced down-regulation of BDNF, loss of PSD-93/95, learning and memory deficits with down-regulation of cAMP content and p-CREB/CREB ratio. Administration of AG (200 and 400 mg/kg) reversed TBI induced down-regulation of BDNF and PSD-93/95, up-regulated the cAMP content and p-CREB/CREB ratio, which resulted in improvement of learning and memory ability.Conclusions: We suspect that AG (200 and 400 mg/kg) might reverse TBI-induced selective loss of postsynaptic proteins and learning and memory deficits with the activation of cAMP/CREB/BDNF signalling pathway.

Inducible nitric oxide inhibitor aminoguanidine, ameliorated oxidative stress, interleukin-6 concentration and improved brain-derived neurotrophic factor in the brain tissues of neonates born from titanium dioxide nanoparticles exposed rats

Introduction: An interaction between oxidative stress, neuroinflammation, and nitric oxide (NO) has been suggested to have a role neurotoxicity. The aim of current research was to investigate the effect of aminoguanidine (AG) as an inducible NO synthase (iNOS) inhibitor, on brain-derived neurotrophic factor (BDNF), oxidative stress, and interleukin-6 (IL-6) concentrations in the brain tissues of neonates born from the rats exposed to titanium dioxide nanoparticles (TiO2 NPs) during gestation.Methods: The pregnant rats were grouped into three and received: (1) saline, (2) TiO2 (200 mg/kg, gavage), and (3) TiO2-AG [200 mg/kg intraperitoneal (IP)]. The treatment was started since the second gestation day up to the delivery time. The neonates born from the rats were deeply anesthetized, sacrificed, and the brains were collected for biochemical evaluations.Results: The neonates born from the rats exposed to TiO2 showed a lower BDNF (p < .001) but a higher IL-6 (p < .01) concentrations in their hippocampal tissue. TiO2 exposure also increased malondialdehyde (MDA) (p < .001) and NO metabolites (p < .001), while diminished thiol (p < .001), superoxide (SOD) (p < .001), and catalase (CAT) (p < .001) in all hippocampal, cortical, and cerebellar tissues. Administration of AG improved BDNF (p < .01) but attenuated IL-6 (p < .01) concentrations in the hippocampal tissue. AG also decreased MDA (p < .001) and NO metabolites (p < .01–p < .001), while increased thiol (p < .01–p < .001), SOD (p < .001), and CAT (p < .05–p < .001) in all cerebellar, hippocampal, cortical, and tissues.Conclusion: The results of the current research revealed that iNOS inhibitor AG, ameliorated oxidative stress, IL-6 concentration, and improved BDNF in the brain tissues of neonates born from TiO2 NPs exposed rats.

Sex‐Unrelated Counteraction by Nicotine of the Endotoxemia‐Evoked Facilitation of Renal Vasodilator Capacity in Rats: Roles of α7/α4β2 nAChRs and HSP70

Nicotine has been shown to alleviate renal inflammation and injury induced by endotoxemia. The current study investigated (i) the sex specificity of the nicotine modulation of hemodynamic and renal vasodilatory responses to endotoxemia in rats, and (ii) the roles of α7 or α4β2 nAChRs and related HSP70/TNFα/iNOS signaling in the interaction. Endotoxemia was induced by i.p. administration of lipopolysaccharide (LPS, 5 mg/kg/day.) for 2 consecutive days and changes in systolic blood pressure (SBP, tail‐cuff plethysmography) and vasodilator responsiveness of isolated perfused kidney to acetylcholine (ACh) or 5′‐N‐ethylcarboxamidoadenosine (NECA, adenosine receptor agonist) were evaluated. Compared with saline values, LPS decreased SBP and increased renal vasodilations induced by cumulative bolus injections of ACh (0.01–7.29 nmol) or NECA (1.6–100 nmol). No changes in serum creatinine or urea were observed. These effects were not sexually differentiated as they were similarly observed in the two rat genders. The LPS facilitation of renal vasodilations were attenuated after concurrent administration of aminoguanidine (iNOS inhibitor, 50 mg/kg), pentoxifylline (TNFα inhibitor, 3 mg/kg), or nicotine (0.5, 1, or 2 mg/kg). We also report that the selective blockade of α7‐nAChRs (methyllycaconitine citrate, MLA) or α4β2‐nAChRs (dihydro‐β‐erythroidine, DHβE) (i) potentiated the enhancing action of LPS on ACh or NECA vasodilations, and (ii) abolished the depressant effect of nicotine on LPS facilitation of renal vasodilatory capacity. A similar inhibition of the nicotine effect was seen after inhibition of HSP70 by quercetin. Alternatively, LPS hypotension was eliminated in rats treated with the DHβE/nicotine or quercetin/nicotine regimen in contrast to no effect for nicotine alone or combined with MLA. These findings establish that nicotine offsets the LPS facilitation of the renal vasodilator propensity, an effect that is sex independent and possibly involves a crosstalk between HSP70 and nAChRs of the α7 and α4β2 types.Support or Funding InformationSupported by the Science and Technology Development Fund, Egypt (STDF Grant No. 14895)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Disruption of the pacemaker activity of interstitial cells of Cajal via nitric oxide contributes to postoperative ileus.

Interstitial cells of Cajal (ICC) serve as intestinal pacemakers. Postoperative ileus (POI) is a gastrointestinal motility disorder that occurs following abdominal surgery, which is caused by inflammation-induced dysfunction of smooth muscles and enteric neurons. However, the participation of ICC in POI is not well understood. In this study, we investigated the functional changes of ICC in a mouse model of POI. Intestinal manipulation (IM) was performed to induce POI. At 24h or 48h after IM, the field potential of the intestinal tunica muscularis was investigated. Tissues were also examined by immunohistochemistry and electron microscopic analysis. Gastrointestinal transit was significantly decreased with intestinal tunica muscularis inflammation at 24h after IM, which was ameliorated at 48h after IM. The generation and propagation of pacemaker potentials were disrupted at 24h after IM and recovered to the control level at 48h after IM. ICC networks, detected by c-Kit immunoreactivity, were remarkably disrupted at 24h after IM. Electron microscopic analysis revealed abnormal vacuoles in the ICC cytoplasm. Interestingly, the ICC networks recovered at 48h after IM. Administration of aminoguanidine, an inducible nitric oxide synthase inhibitor, suppressed the disruption of ICC networks. Ileal smooth muscle tissue cultured in the presence of nitric oxide donor, showed disrupted ICC networks. The generation and propagation of pacemaker potentials by ICC are disrupted via nitric oxide after IM, and this disruption may contribute to POI. When inflammation is ameliorated, ICC can recover their pacemaker function.