Nitric Oxide Levels In Rats Research Articles

Effect of Polycaprolactone Scaffold Containing Myrtus Communis Extract and Silver Nanoparticles on the Burn Wound Infection Induced by Methicillinresistant Staphylococcus Aureus in Rats

Background and Objectives: Regarding the important role of Staphylococcus aureus in burn wound infection, the present study aims to investigate of the effect of Polycaprolactone (PCL) scaffold containing Myrtus communis extract and silver nanoparticles on the healing of burn wound infections induced by Methicillin-Resistant Staphylococcus Aureus (MRSA) in rats. Methods: In this experimental study, 42 male Wistar rats were divided into seven groups of 6. After anesthesia, second-degree burns on the back of the rats’ necks were created and MRSA was then injected into the wound area. The rats’ wounds were treated daily with nanofiber PCL containing Myrtus communis extract and silver nanoparticles. Antimicrobial properties, wound healing percentage, wound area, malondialdehyde and nitric oxide levels, and total antioxidant capacity were measured. Data were analyzed in GraphPad software using Tukey’s test and ANOVA. Results: The wound area measurement showed the better effects on would healing in the groups treated by PCL+Myrtus communis extract and PCL+Myrtus communis extract+silver nanoparticles compared other groups. In bacteriological studies, the groups treated by PCL+Myrtus communis extract and PCL+Myrtus communis extract+silver nanoparticle showed more reduced bacterial growth compared to the PCL alone and positive control groups. Moreover, biochemical tests showed a decrease in malondialdehyde and nitric oxide levels in rats treated by PCL+Myrtus communis extract compared to other groups. Conclusion: Myrtus communis extract and silver nanoparticles can cause changes in PCL properties, which have an important role in reducing the time required for wound healing and in preventing the progression of MRSA-induced wound infection

Liver protection from acetaminophen hepatotoxicity using copper(I)-nicotinic acid complex

The present study was performed to investigate the hepatotoxicity of acetaminophen and the possible hepatoprotective effect of copper(I)-nicotinate in rats through biochemical light and electron microscopy studies. Two groups of rats (39 in total) were used: group I (15 rats) received acetaminophen by intraperitoneal injection in a dose of 1000 mg/kg. While group II (15 rats) received an oral dose of 800 μg/kg copper(I)-nicotinate dissolved in 0.5 mL of saline three times through 24 h and 1 h after the last dose, and 9 rats were kept as control. Blood and tissue samples for biochemical, light, and electron microscopy were collected after 4, 12, and 24 h. Biochemical results showed a significant elevation in ALT, AST, and nitric oxide levels in rats who received acetaminophen only. In contrast, the corresponding levels of treated rats with the copper complex showed a less significant elevation in ALT, AST, and nitric oxide. Light microscopic examination of liver tissue taken from intoxicated animals showed congestion of the vasculature with hydropic and fatty degeneration. Centrilobular necrosis of the hepatocytes with glycogen depletion was observed in the centrilobular areas. Ultrastructural examination showed fatty degeneration, mitochondrial swelling, severe irregular dilatation of RER and SER, loss of glycogen granules, and pyknosis of the nuclei. Examination of livers of animals that received copper complex before intoxication revealed only cup-shaped mitochondria, a mild degree of fatty degeneration, and glycogen depletion with no evidence of necrosis. This work provides evidence for the antioxidant properties of the copper(I)-nicotinate complex and illustrates the pathological changes induced by acetaminophen in liver tissue.

Pharmacological Evaluation of Beta‐Hydroxifosphocarnitine in No‐Alcoholic Steatohepatitis Induced in Rats

Aim Evaluate the pharmacological effect of Β-Hydroxyphosphocarnitine (β-HFC) on non-alcoholic steatohepatitis induced in rats. Introduction Non-alcoholic steatohepatitis (NASH) is a disease with high prevalence, usually accompanied on metabolic syndrome. Currently the treatment to NASH is pioglitazone. However, it is reported that pioglitazone causes several side effects reason to stop treatment. L-carnitine has pharmacological effect in the metabolic syndrome, but it is poorly absorbed. The β-HFC is an analogue of L-carnitine that has shown effect on metabolic syndrome and maintaining its pharmacological properties. Method The NASH model was developed in male Wistar rats by ingesting carbonated drink as a source of fructose, coconut oil and carbon tetrachloride. 3 groups were formed with NASH (n = 8); NASH, NASH -β-HFC and NASH-pioglitazone. Another 3 groups of healthy rats (n = 8); control, control-β-HFC and control-pioglitazone. The effect of β-HFC in NASH rats was evaluated by histological sections of the liver with Masson's hematoxylin eosin and trichromic staining. Quantification of liver enzymes, triglycerides, cholesterol and glucose in serum by spectrophotometric kit. Insulin levels were determined by Elisa. Results We previously reported that β-HFC reduced serum triglyceride levels in NASH rats. The levels of glucose, insulin and nitric oxide (NO) were quantified and are the ones that we will report on this occasion. Insulin levels were low in the NASH rats even with the β-HFC treatment compared to the control rats, (25.9 ± 6, 30.0 ± 10 and 121.1 ± 69.5 ng / ml respectively). The pancreas can be damaged by excess fatty acids (FA), altering insulin production. No significant difference was observed in glucose levels between the control and NASH groups (123.2 ± 50.6 and 134.3 ± 19.1 mg/dL respectively). High glucose levels would be expected in NASH rats, however, since insulin resistance is not observed, it could justify that glucose is not elevated. NO is a source of production of reactive species. The rats with NASH showed higher levels of NO than those of the control group (0.054, 0.01 µM / µl respectively). β-HFC was shown to reduce NO levels in rats with NASH (0.03µM / µl). β-HFC enhances the fatty acid oxidation process which can result in decreased production of reactive species. Conclusion: β-HFC enhances key alterations for NASH progression such as DNL and NO production. Conclusion: β-HFC promises to be effective for the treatment of NAHS by improving key alterations for the progression of NASH such as DNL and NO production.

Nitric oxide and asymmetric dimethyl arginine (ADMA) levels in an experimental hydronephrotic kidney caused by unilateral partial ureteral obstruction.

ABSTRACTAim Our aim is to measure asymmetric dimethyl arginine and nitric oxide levels in rats with induced unilateral acute ureteral obstruction to research the effects on the kidney.Material and Methods The study included 21 adolescent (average age 6 weeks) Sprague-Dawley male rats weighing between 240-290g divided at random into 3 groups. Group-1: Control group (n=6): underwent no procedures. Group-2: Sham group (n=6): underwent the same procedures as the experimental group without ureter and psoas muscle dissection. Group-3: Group with induced partial unilateral ureteral obstruction (n=9). All rats were sacrificed after 12 weeks. Superoxide dismutase enzyme activity and nitrite and nitrate salt levels were measured in renal tissue. Plasma nitrite-nitrate and ADMA levels were examined.Results In the experimental group histopathological changes observed included renal pelvis dilatation, flattened papillae, sclerotic glomerulus and fibrosis. In the experimental group tissue SOD and blood ADMA levels were higher than the control and sham groups (p<0.05) while tissue NO and plasma NO values were lower than in the sham and control groups (p<0.05).Conclusion Oxidative stress and disruption of NO synthesis play an important role in renal function and histopathological changes after obstructive renal disease. To prevent renal complications developing after obstructive nephropathy we believe that a new strategy may be research on reducing ADMA.

Effects of high intensity exhaustive exercise on SOD, MDA, and NO levels in rats with knee osteoarthritis.

The aim of this study was to investigate the impact of high intensity exhaustive exercise on nitric oxide (NO), malondialdehyde (MDA), and superoxide dismutase (SOD) expression in rats with knee osteoarthritis. Sprague Dawley rats were randomly divided into control (N = 5) and model (N = 35) groups; the model group was further divided into quiet (N = 5), low- (N = 15) and high- (N = 15) intensity exhaustive exercise groups. The low- and high-intensity groups were randomly divided into pre-exercise (N = 5), immediate post-exercise (N = 5), and 24-h post-exercise (N = 5) groups according to different time points for detection. NO, MDA, and SOD levels were compared between each group. The SOD levels in the quiet, low-, and high-intensity exhaustive exercise groups were lower than that in the control group, whereas the NO and MDA levels were higher in the former groups than in the controls (P < 0.05). The SOD level in the 24-h post-low intensity exhaustive exercise group was higher than that in the 24-h post-high intensity exhaustive exercise group, whereas the NO and MDA levels were lower in the 24-h post-low intensity than in the post-high intensity exercise group (P < 0.05). Overall, the results demonstrated that with the increase of exercise intensity, the SOD activity in the rats with knee osteoarthritis decreased gradually, whereas the MDA and NO levels gradually increased. Thus, the greater the exercise intensity, the more serious the impact on knee osteoarthritis.

Ethanol extracts of centella asiatica leaf improves memory performance in rats after chronic stress via reducing nitric oxide and increasing Brain-Derived Neurotrophic Factor (BDNF) Concentration

Abstract- Background: Centella asiatica is herbaceous plant that has medicinal value to improve learning and memory. Brain- derived neurotrophic factor (BDNF) has a significant role in memory formation process, while oxidative stress causes memory impairment. Objective: This study aimed to investigate the effects of ethanol extracts of Centella asiatica leaf on memory performance and serum BDNF (neurotrophins) and Nitric Oxide(NO) concentration of rats following chronic electrical stress. Materials and Methods : Twenty male rats (Sprague Dawley) were divided into four groups: control/aquadest group and groups treated with three different doses (mg/kg) of Centella asiatica :150 (CeA150), 300 (CeA300) and 600 (CeA600). Memory performance was tested using probe test in Morris Water Maze before and after oral administration of ethanol extracts of Centella asiatica leaf followed by electrical stress for 28 days. At the last day of memory exercise following chronic stress, blood sample was taken from periorbital veins of all rats. Concentration of serum BDNF and total NO was assessed using ELISA. Data were analyzed using one way ANOVA. Results: Treatment groups had higher percentage in probe test water maze and serum BDNF concentration after chronic stress. Mean time percentage (%) of probe test in water maze performance for control group, CeA150, CeA300, and CeA600 were 53.33±2.43, 55.78±4.16, 63.33±4.07, and 73.55±3.29 (p<0.05). Mean concentration of serum BDNF (ng/ml) for control group, CeA150, CeA300, and CeA600 were 1.52±0.89, 1.49±0.20, 1.73±0.15, and 2.16±0.20 (p<0.05 vs control group). Control group had higher serum NO concentration compared to all treatments groups. Mean concentration of serum NO (μmol/L) for control group, CeA150, CeA300, and CeA600 were 5.94±0.52, 3.98±0.35, 3.06±0.33, and 2.82±0.21 (p<0.05). Conclusion: Ethanol extracts of Centella asiatica leaf increases memory performance and serum BDNF concentration, and also decreases Nitric Oxide levels in rats after chronic stress.

Pu-erh Tea Reduces Nitric Oxide Levels in Rats by Inhibiting Inducible Nitric Oxide Synthase Expression through Toll-Like Receptor 4

Pu-erh tea undergoes a unique fermentation process and contains theabrownins, polysaccharides and caffeine; although it is unclear about which component is associated with the down regulation of nitric oxide levels or how this process is mediated. To address this question we examined the effects of pu-erh tea on nitric oxide synthase (NOS) genes. Cohorts of rats were separately given four-week treatments of water as control, pu-erh tea, or the tea components: theabrownins, caffeine or polysaccharides. Five experimental groups were injected with lipopolysaccharides (LPS) to induce nitric oxide (NO) production, while the corresponding five control groups were injected with saline as a negative control. The serum and liver NO concentrations were examined and the NOS expression of both mRNA and protein was measured in liver. The results showed that the rats which were fed pu-erh tea or polysaccharides had lower levels of NO which corresponded with the down-regulation of inducible nitric oxide synthase (iNOS) expression. We further demonstrate that this effect is mediated through reduction of Toll-like receptor 4 (TLR4) signaling. Thus we find that the polysaccharide components in pu-erh tea reduce NO levels in an animal model by inhibiting the iNOS expression via signaling through TLR4.

Neuroprotective effect of alpha-asarone on spatial memory and nitric oxide levels in rats injected with amyloid-β (25–35)

The chemical α-asarone is an important active substance of the Acori graminei rhizome (AGR). It has pharmacological effects that include antihyperlipidemic, antiinflammatory, and antioxidant activity. Our aim was to study the effects α-asarone on nitric oxide (NO) levels in the hippocampus and temporal cortex of the rat after injection of the fraction 25–35 from amyloid-β (Aβ (25–35)). In addition we examined the working spatial memory in an eight-arm radial maze. Our results showed a significant increase of nitrites in the hippocampus and temporal cortex of Aβ (25–35)-treated rats. Other evidence of neuronal damage was the expression of a glial-fibrillar-acid protein and a silver staining. There were impairments in the spatial memory evaluated in the eight-arm radial maze. We wanted to determine whether α-asarone improves the memory correlated with NO overproduction and neuronal damage caused by the injection of Aβ (25–35) into rats. Then animals received a 16-day treatment of α-asarone before the Aβ (25–35) injection. Our results show a significant decrease of nitrite levels in the hippocampus and temporal cortex, without astrocytosis and silver-staining cells, which correlates with memory improvement in the α-asarone-treated group. Our results suggest that α-asarone may protect neurons against Aβ (25–35)–caused neurotoxicity by inhibiting the effects of NO overproduction in the hippocampus and temporal cortex.

Nitric oxide levels in rat hypothalamus are increased by restraint stress and decreased by biting

Mastication, which includes biting, is of great importance not only for the intake of food but also for the mental, physical and physiological functioning of the body. For example, biting suppresses the stress response. Although biting and nitric oxide (NO) appear to modulate brain dynamics during stress, the underlying mechanisms have not been elucidated. In this study, we examined the effect of biting during restraint stress on NO levels in the rat hypothalamus. To this end, we used NO-selective electrodes that were calibrated by electron spin resonance (ESR) spectroscopy. We implanted the electrodes and probes for perfusion of solutions into the brain of rats, near the hypothalamus. Saline containing 10 mM N-nitro-L-arginine methyl ester (L-NAME), which is one of the most commonly used inhibitors of nitric oxide synthase (NOS), was employed as the perfusate. L-NAME prevented increases in NO levels in the rat hypothalamus that were induced by restraint stress and biting. Hypothalamic NO levels in rats under restraint stress for 180 min were increased above levels observed in unrestrained control rats. The increase in hypothalamic NO (from 2.123 μM to 4.760 μM) during restraint stress was reduced after biting for 30 min. The decay rate of NO levels after biting was −0.584 pA/min (−0.071 μM/min). We conclude that: (i) it is possible to evaluate NO levels in vivo in rat brain; (ii) NO levels are increased by restraint stress; and (iii) this increase is prevented by biting behavior.

EUK-134 Reduces Renal Dysfunction and Injury Caused by Oxidative and Nitrosative Stress of the Kidney

Background/Aims: Oxidative and nitrosative stress plays important roles in the pathogenesis of renal ischemia/reperfusion (I/R) injury. Here we investigate the effect of EUK-134, a synthetic superoxide dismutase and catalase mimetic, (i) on renal dysfunction and injury caused by I/R in vivo and (ii) on proximal tubular cell (PTC) injury and death caused by oxidative and nitrosative stress. Methods: Rats, subjected to bilateral renal ischemia (45 min) followed by reperfusion (6 h), were administered EUK-134 (0.3 and 3 mg/kg, i.v.) prior to and during reperfusion, after which biochemical and histological indicators of renal dysfunction and injury were measured. The expression of poly(ADP-ribose) (PAR) and inducible nitric oxide (NO) synthase (iNOS) and nitrotyrosine formation were determined immunohistochemically and used as indicators of oxidative and nitrosative stress. Primary cultures of rat PTCs, isolated and cultured from the kidney cortex, were incubated with hydrogen peroxide (H₂O₂; 1 mM for 2 h) in the presence of increasing concentrations of EUK-134 (1–100 µM) after which PTC injury and death were measured. The effects of EUK-134 on serum levels of NO in rats subjected to renal I/R or on NO production by PTCs incubated with interferon-γ (IFN-γ, 100 IU/ml) and bacterial lipopolysaccharide (LPS, 10 µg/ml) in combination for 24 h were also measured. Results: EUK-134 produced a significant reduction in renal dysfunction and injury caused by I/R. Specifically, serum creatinine levels, an indicator of renal dysfunction, were reduced from 227 ± 11 (n = 12, I/R only) to 146 ± 9 µM (n = 12, I/R +3 mg/kg EUK-134). Urinary N-acetyl-β-D-glucosaminidase activity, an indicator of tubular damage, was reduced from 42 ± 5 (n = 12, I/R only) to 22 ± 3 IU/l (n = 12, I/R +3 mg/kg EUK-134). EUK-134 significantly reduced renal injury caused by oxidative stress in vivo (reduction in PAR formation), and in vitro EUK-134 reduced PTC injury and death caused by H₂O₂. However, EUK-134 also reduced nitrosative stress caused by I/R in vivo (reduction of iNOS expression and nitrotyrosine formation), which was reflected by a significant reduction in serum NO levels in rats subjected to renal I/R. Specifically, serum NO levels were reduced from 57 ± 12 (n = 12, I/R only) to 23 ± 3 mM (n = 12, I/R +3 mg/kg EUK-134). In vitro, EUK-134 significantly reduced NO production by PTCs incubated with IFN-γ/LPS. Conclusion: We propose that EUK-134 reduces renal I/R injury not only via reduction of oxidative stress, but also by reducing nitrosative stress caused by renal I/R.

NO as an Indicator of Portal Hemodynamics and the Role of iNOS in Increased NO Production in CCl4-Induced Liver Cirrhosis

It is well known that nitric oxide, a vasodilator, is overproduced in liver cirrhosis. This study was designed to elucidate the role of nitric oxide (NO) in portal hemodynamics and to determine the mechanism underlying the increased serum NO levels in rats with liver cirrhosis induced by the oral intake of CCl4. Using rats, liver cirrhosis was induced by oral administration of CCl4. The serum levels of NO2−/NO3−(NOx) were measured, and portal hemodynamic parameters were evaluated with and without the administration of the NO synthase inhibitorNω-nitro-l-arginine (NNA). Furthermore, Northern blot analysis was used to detect iNOS and cNOS mRNA, and immunohistochemical methods were used to detect iNOS-like immunoreactivity. In cirrhotic rats, the portal flow had increased significantly and the portal resistance had decreased significantly when compared with normal control rats. Hepatic capillary flow in the cirrhotic rats was similar to the control rats. NNA decreased portal flow and increased portal resistance in both groups, but the change was greater in the cirrhotic rats than in controls. The serum levels of NOxwere significantly higher in cirrhotic rats than in normal control rats and were positively correlated with portal flow and negatively correlated with portal resistance. The expression of iNOS mRNA, which was barely detectable in control rats, had increased in all organs of the cirrhotic rats, whereas no significant increase in cNOS mRNA was found in any of the organs from cirrhotic rats. The immunohistochemical analysis was generally consistent with the results of the Northern blot analysis. In the control rats, only the bronchial epithelial cells were stained with the anti-iNOS antibody, but in cirrhotic rats, the bronchial cells in the lungs as well as the histiocytic mesenchymal cells in all organs, and the alveolar epithelial cells of the lungs, were stained. This study demonstrated that NO plays a significant role in portal hypertensive hemodynamics in CCl4-induced liver cirrhosis, and that NO is a useful indicator for the evaluation of portal hypertension. Furthermore, the increased serum levels of NO were found to be derived at least in part from the increased expression of iNOS mRNA in the liver, spleen, and lung.