Administration Of N-acetyl-L-cysteine Research Articles

Akt Signaling and Nitric Oxide Synthase as Possible Mediators of the Protective Effect of N-acetyl-L-cysteine in Prediabetes Induced by Sucrose.

The aim of this work was to evaluate possible mechanisms involved in the protective effect of N-acetyl-L-cysteine (NAC) on hepatic endocrine-metabolic, oxidative stress, and inflammatory changes in prediabetic rats. For that, normal male Wistar rats (60 days old) were fed for 21 days with 10% sucrose in their drinking water and 5 days of NAC administration (50 mg/kg, i.p.) and thereafter, we determined: serum glucose, insulin, transaminases, uric acid, and triglyceride levels; hepatic fructokinase and glucokinase activities, glycogen content, lipogenic gene expression; enzymatic and non-enzymatic oxidative stress, insulin signaling pathway, and inflammatory markers. Results showed that alterations evinced in sucrose-fed rats (hypertriglyceridemia, hyperinsulinemia, and high liver fructokinase activity together with increased liver lipogenic gene expression and oxidative stress and inflammatory markers) were prevented by NAC administration. P-endothelial nitric oxide synthase (P-eNOS)/eNOS and pAKT/AKT ratios, decreased by sucrose ingestion, were restored after NAC treatment. In conclusion, the results suggest that NAC administration improves glucose homeostasis, oxidative stress, and inflammation in prediabetic rats probably mediated by modulation of the AKT/NOS pathway. Administration of NAC may be an effective complementary strategy to alleviate or prevent oxidative stress and inflammatory responses observed in type 2 diabetes at early stages of its development (prediabetes).

Effect of N-acetyl-L-cysteine on Testicular Tissue in Busulfan-Induced Dysfunction in the Male Reproductive System.

This study aimed to evaluate the protective effect of N-acetyl-L-cysteine (NAC) as an antioxidant on busulfan-induced testicular dysfunction in mice and elucidate its possible mechanism of action. Thirty-two C57BL/6 male mice were randomly divided into four groups (n=8/group) as follows: (1) control group (oral administration of saline [0.1 mL daily] for 35 days); (2) NAC group (oral administration of NAC [10 mg/kg daily] for 35 days); (3) busulfan group (double intraperitoneal injections of 20 mg/kg; total dose of 40 mg/kg); and (4) busulfan+NAC group (after double intraperitoneal injections of 20 mg/kg; total dose of 40 mg/kg, NAC administration [10 mg/kg daily] for 35 days). The testes were removed, weighed, and subjected to sperm parameter analysis and morphology assessment. Reproductive hormone, serum/testicular reactive oxygen species (ROS) level, oxidative stress and antioxidant markers were evaluated. The testicular expression of Nrf2 and HO-1 was examined using RT-qPCR. Busulfan treatment significantly decreased testicular weight, sperm count, and serum testosterone levels. Atrophy and degeneration of germinal epithelium were observed in the busulfan group. NAC administration after busulfan treatment partially attenuated the deterioration of testis weight, sperm quality, serum hormones, histomorphometric changes, and oxidative and antioxidative status. NAC treatment resulted in a considerable improvement in Nrf2 and HO-1 mRNA expression levels. This study provides compelling evidence that NAC as a potent antioxidant has significant protective effects against busulfan-induced male reproductive impairment possibly through modification of the Nrf2/HO-1 signaling pathway.

N-Acetyl-L-Cysteine Protects Organ Function After Hemorrhagic Shock Combined With Seawater Immersion in Rats by Correcting Coagulopathy and Acidosis.

BackgroundThe mortality of trauma combined with seawater immersion is higher than that of land injury, however, research on how to treat this critical case and which treatments to adopt is lacking.MethodsThe effect of the thiol compound, N-acetyl-L-Cysteine (NAC), on survival, acidosis, coagulopathy, vital signs, oxidative stress, and mitochondrial and multi-organ function was assessed in a rat model of hemorrhagic shock combined with seawater immersion (Sea-Shock).ResultsHemorrhagic shock combined with seawater immersion caused a severe lethal triad: multi-organ impairment, oxidative stress, and mitochondrial dysfunction. NAC (30 mg/kg) with lactated Ringer’s (LR) solution (2 × blood volume lost) significantly improved outcomes compared to LR or hetastarch (HES 130/0.4) alone. NAC significantly prolonged survival time to 52.48 ± 30.09 h and increased 72 h survival rate to 11/16 (68%). NAC relieved metabolic acidosis and recovered the pH back to 7.33. NAC also restored coagulation, with APTT, PT, and PT-INR decreased by 109.31, 78.09, and 73.74%, respectively, while fibrinogen level increased 246.23% compared with untreated Sea-Shock. Administration of NAC markedly improved cardiac and liver function, with some improvement of kidney function.ConclusionThe addition of NAC to crystalloid resuscitation fluid alleviated oxidative stress, restored redox homeostasis, and provided multi-organ protection in the rats after Sea-Shock. NAC may be an effective therapeutic measure for hemorrhagic shock combined with seawater immersion.

Antioxidant, histopathological and biochemical outcomes of short-term exposure to acetamiprid in liver and brain of rat: The protective role of N-acetylcysteine and S-methylcysteine

The present study was conducted to investigate the protective effects of N-Acetyl-L-cysteine (NAC) and S-methyl- L-cysteine (SMC) against hepatic oxidative stress and brain damage induced by acetamiprid (ACP) in rats, which were evaluated by histopathological changes, measuring serum biomarkers and antioxidant defense systems. In this study, 42 rats were randomly divided into 6 groups and administered by intraperitoneally for one week: the control group, the sham group (normal saline), ACP alone (5 mg/kg) (group1), NAC alone (160 mg/kg) (group2), ACP + SMC (100 mg/kg) (group3), ACP + NAC (group 4) and ACP + NAC + SMC (group 5). Our results showed that acetamiprid induces liver injures including infiltration of inflammatory cells, congestion and altered histo-architecture and brain damages including gliosis, hyperemia and necrosis. The biochemical analyses showed that acetamiprid significantly altered the structural and biochemical profiles of liver which may be due to the loss of integrity of cell membranes. Furthermore, antioxidant parameters results of ACP group revealed that glutathione (GSH) and total antioxidant capacity (TAC) levels decreased significantly, while lipid peroxidation (LPO) content and glutathione-S-transferase (GST) and catalase (CAT) activities increased in both tissues (P < 0.05), suggesting tissue oxidative damage, which was also confirmed histopathological. Conversely, administration of NAC and SMC ameliorated LPO, GSH content and antioxidant enzymes system considerably (P < 0.05) in both tissues. Moreover, NAC and SMC administration also improved liver and brain malfunction. These results indicate that both NAC and in to a lesser amount SMC have a potent antioxidant protection in both tissues of rat against ACP-induced oxidative stress.

An antioxidant suppressed lung cellular senescence and enhanced pulmonary function in aged mice

Oxidative stress is one of the major causes of cellular senescence in mammalian cells. The excess amount of reactive oxygen species generated by oxygen metabolism is pathogenic and facilitates tissue aging. Lung tissue is more susceptible to oxidative stress than other organs because it is directly exposed to environmental stresses. The aging of lung tissues increases the risk of chronic diseases. Senescent cells accumulate in tissues during aging and contribute to aging-associated morbidity; however, the roles of cellular senescence in lung aging and diseases have not yet been elucidated in detail.To clarify the physiological role of oxidative stress-induced cellular senescence in aging-associated declines in pulmonary function, we herein investigated the effects of the antioxidant N-acetyl-L-cysteine (NAC) on lung cellular senescence and aging in mice. The administration of NAC to 1-year-old mice reduced the expression of senescence-associated genes in lung tissue. Pulmonary function and lung morphology were partly restored in mice administered NAC. Collectively, these results suggest that oxidative stress is a major inducer of cellular senescence in vivo and that the control of oxidative stress may prevent lung aging and diseases.

Rationale for the use of N-acetylcysteine in both prevention and adjuvant therapy of COVID-19.

COVID‐19 may cause pneumonia, acute respiratory distress syndrome, cardiovascular alterations, and multiple organ failure, which have been ascribed to a cytokine storm, a systemic inflammatory response, and an attack by the immune system. Moreover, an oxidative stress imbalance has been demonstrated to occur in COVID‐19 patients. N‐ Acetyl‐L‐cysteine (NAC) is a precursor of reduced glutathione (GSH). Due to its tolerability, this pleiotropic drug has been proposed not only as a mucolytic agent, but also as a preventive/therapeutic agent in a variety of disorders involving GSH depletion and oxidative stress. At very high doses, NAC is also used as an antidote against paracetamol intoxication. Thiols block the angiotensin‐converting enzyme 2 thereby hampering penetration of SARS‐CoV‐2 into cells. Based on a broad range of antioxidant and anti‐inflammatory mechanisms, which are herein reviewed, the oral administration of NAC is likely to attenuate the risk of developing COVID‐19, as it was previously demonstrated for influenza and influenza‐like illnesses. Moreover, high‐dose intravenous NAC may be expected to play an adjuvant role in the treatment of severe COVID‐19 cases and in the control of its lethal complications, also including pulmonary and cardiovascular adverse events.

Reduction of Leishmania activity by N‐acetyl ‐L‐cysteine: in vivo study

Leishmaniasis is a emergent disease characterized by different clinical manifestations in both humans and dogs. The clinical manifestation of this disease comprises a widespread range of expressions, such as skin ulcers at the set of the infection or dissemination in visceral organs followed by leucopenia, anemia, fever and weakness. Predominant clinical features of cutaneous leishmaniasis are ulcerative painless skin lesions. Several data reported that pain is associated with human and dog leishmaniasis, out with areas of painless ulcerative lesions per se. Actually, current medications used for leishmaniasis management are characterized by several side effects and, in addition, some cases of the disease are refractory to the treatment. On this background it is mandatory the identification of new and safe candidates for designing less toxic and low‐cost remedies. Therefore, the search for new leishmanicidal compounds is indispensable. In the present paper we investigated how orally N‐acetyl ‐L‐cysteine (NAC) supplementation affected parameters of inflammation and pain in subcutaneous Leishmania (L). amazonensis infected BALB/c mice, to better understand the contribution of this treatment in the pathogenesis and progress of leishmaniasis. The findings of our study provided the scientific data demonstrating that L. amazonensis infection induces inflammation and pain in BALB/c mice that are reversed by administration of NAC.

Fosfomycin trometamol and N-acetyl-L-cysteine as combined oral therapy of difficult-to-treat chronic bacterial prostatitis: Results of a pilot study

This paper presents the results of a pilot study of difficult-to-treat patients (exhibiting several previous treatment failures or detection of extended-spectrum beta-lactamase [ESBL] strains) with chronic bacterial prostatitis (CBP) who underwent treatment with fosfomycin trometamol (FT) and N-acetyl-L-cysteine (NAC). Twenty-eight patients with clinically- and microbiologically-confirmed CBP who attended a single urological institution between January 2018 and March 2019 were treated with oral administration of 3 g FT once a day for 2 days, followed by a dose of 3 g every 48 h for 2weeks, in combination with oral administration of NAC 600 mg once a day for 2 weeks. Clinical and microbiological analyses were carried out at the time of admission (T0) and during follow-up at 1month (T1) and 6 months (T2) after the end of treatment. Symptoms were assessed by the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and International Prostatic Symptom Score (IPSS), and quality of life was assessed by Quality of Well-Being (QoL) questionnaires. Isolated strains were Escherichia coli (23 patients), Enterococcus spp. (3 patients), and Klebsiella oxytoca (2 patients). ESBL strain was found in 19 (67.8%) patients. Microbiological eradication was documented in 21 (75%) patients at the second follow-up visit and clinical cure was achieved in 20 (71.4%) patients. Significant changes on questionnaires were recorded between baseline and follow-up visits. Fifteen of 19 patients (78.9%) with ESBL strains were cured. No significant side effects were reported. FT in combination with NAC is a promising alternative therapy in difficult-to-treat CBP patients.

N-acetyl-L-cysteine reduces Leishmania amazonensis-induced inflammation in BALB/c mice

BackgroundLeishmaniasis is a emergent disease characterized by different clinical manifestations in both humans and dogs. Predominant clinical features of cutaneous leishmaniasis are ulcerative painless skin lesions. Several data reported that pain is associated with human and dog leishmaniasis, out with areas of painless ulcerative lesions per se. Actually, current medications used for leishmaniasis management are characterized by several side effects and, in addition, some cases of the disease are refractory to the treatment. On this background it is mandatory the identification of new and safe candidates for designing less toxic and low-cost remedies. Therefore, the search for new leishmanicidal compounds is indispensable.MethodsIn the present paper we investigated the effect of orally N-acetyl-L-cysteine (NAC) supplementation at dose of 200 mg/Kg for 10 weeks, in subcutaneous Leishmania (L). amazonensis infected BALB/c mice. And evaluating the effect of NAC on inflammatory response such as TNF-α, IL-6, IL-1β levels, and on thermal and mechanical hyperalgesia.ResultsIn the present paper we showed how NAC supplementation affected parameters of oxidative stress (GSH, MDA, SOD), inflammation such as cytokines levels (IL-1β, IL-6, TNFα) and mast cell activation and consequently on induced pain, during leishmaniosis in BALB\\c mice.ConclusionsThe findings of our study provided the scientific data demonstrating that L. amazonensis infection induces inflammation and pain in BALB/c mice that are reversed by administration of NAC.

EV71 infection induces cell apoptosis through ROS generation and SIRT1 activation.

Several studies have substantiated the correlation between reactive oxygen species (ROS) and Sirtuin 1 (SIRT1). Normally, enterovirus 71 (EV71) is associated with severe clinical manifestations and death. However, the effect of EV71 on the induction of cellular death and the interplay between ROS/SIRT1 in cell death has not been confirmed yet. In the current study, an increase in the number of apoptotic cells was observed as soon as the EV71 infection was initiated in cells and mice. Furthermore, EV71 infection also promoted a rise in the levels of three commonly known proinflammatory cytokines, interleukin 1β (IL-1β), IL-6, and tumor necrosis factor-α. During EV71-induced apoptosis in the different cell lines, ROS generation and SIRT1 downregulation were observed. Further investigations showed that the administration of ROS inhibitor, N-acetyl- l-cysteine (NAC), reduced the level of apoptosis and inflammation, reduced EV71 propagation, and increased SIRT1 expression in EV71-infected cells. In addition, combined administration of NAC and EX527 (SIRT1 inhibitor) restored apoptosis in the EV71-infected cells, which was reduced due to NAC. This data demonstrated that ROS generation is positively associated with EV71-induced apoptosis and inflammation, while this effect could be reversed by SIRT1 inhibition. Collectively, we have shown that EV71 induces apoptosis and inflammation by promoting ROS generation and reducing SIRT1 expression.

Beneficial Effects of N-Acetyl-L-cysteine or Taurine Pre- or Post-treatments in the Heart, Spleen, Lung, and Testis of Hexavalent Chromium-Exposed Mice.

Hexavalent chromium[Cr(VI)] compounds may induce toxic effects, possibly via reactive intermediates and radicals formed during Cr(VI) reduction. In this study, we probed the possible effects of N-acetyl-L-cysteine (NAC) and taurine pre- or post-treatments on Cr(VI)-induced changes in lipid peroxidation and nonprotein thiols (NPSH) in mice heart, lung, spleen, and testis tissues. The mice were randomly assigned to six groups, consisting of control, Cr(VI)-exposed (20 mg Cr/kg, intraperitoneal ,ip), NAC (200mg/kg, ip) as pre-treatment and post-treatment, and taurine (1g/kg, ip) pre-treatment and post-treatment groups. Lipid peroxidation and NPSH levels were determined and the results were compared with regard to tissue- and antioxidant-specific basis. Exposure to Cr(VI) significantly increased lipid peroxidation in all tissues as compared to the control (p < 0.05); and consistent with this data, NPSH levels were significantly decreased (p < 0.05). Notably, administration of NAC and taurine, either before or after Cr(VI) exposure, was able to ameliorate the lipid peroxidation (p < 0.05) in all tissues. In the case of NPSH content, while the decline could be alleviated by both NAC and taurine pre- and post-treatments in the spleen, diverging results were obtained in other tissues. The effects of Cr(VI) on the lung thiols were abolished by pre-treatment with NAC and taurine; however, post-treatments could not exert significant effect. While thiol depletion in the heart was totally replenished by NAC and taurine administrations, NAC pre-treatment was partially more effective than post-treatment. In contrast with lipid peroxidation data, NAC treatment could not provide a statistically significant beneficial effect on NPSH content of the testis, whereas the effect in this tissue by taurine was profound. Thus, these data highlight the importance of tissue-specific factors and the critical role of administration time. Overall, our data suggest that NAC and taurine may have potential in prevention of Cr(VI)-induced toxicity in the heart, lung, spleen, and testis tissues.

Deletion of REDD1 Prevents Hyperglycemia-Induced Reactive Oxygen Species Accumulation and Retinal Cell Death

Apoptosis of retinal neurons is accelerated by diabetes and the onset of increased cell death occurs early in disease progression. The present study was designed to evaluate molecular defects that contribute to diabetes-induced neuroretinal apoptosis and visual dysfunction. We recently demonstrated that the stress response protein REDD1 is induced by hyperglycemia in the retina of diabetic mice in a manner that contributes to neuronal cell death and visual dysfunction. One potential mechanism whereby REDD1 promotes neuronal apoptosis is through upregulation of reactive oxygen species (ROS), as the protein forms a pro-oxidant complex. In the retina of streptozotocin-induced diabetic mice, ROS levels, neuronal cell death, and REDD1 expression were increased concomitant with attenuation of contrast sensitivity thresholds, as assessed by behavioral optomotry. In R28 retinal cells in culture, hyperglycemic conditions increased REDD1 expression, ROS levels, and cell death. However, addition of the antioxidant N-acetyl-L-cysteine (NAC) to culture medium was sufficient to prevent the increase in ROS and cell death in response to hyperglycemic conditions. Moreover, REDD1-deficient cells did not exhibit increased ROS or cell death in response to hyperglycemic conditions. Similarly, in REDD1-deficient diabetic mice, ROS levels and cell death in retina were similar to that observed in nondiabetic mice. Finally, oral administration of NAC improved contrast sensitivity in diabetic mice relative to vehicle treated diabetic controls, demonstrating a key role for ROS levels in diabetes-induced visual dysfunction. Overall, the findings support therapeutic approaches targeting REDD1 and ROS production in the prevention of diabetes-induced visual dysfunction. Disclosure W.P. Miller: None. A. Toro: None. M.D. Dennis: None.

Therapeutic effects of N-acetyl-L-cysteine on liver damage induced by long-term CCl4 administration.

N-acetyl-L-cysteine (NAC) is a drug routinely used in several health problems, e.g. liver damage. There is some information emerged on its negative effects in certain situations. The aim of our study was to examine its ability to influence liver damage induced by long-term burden. We induced liver damage by CCl4 (10 weeks) and monitored the impact of parallel NAC administration (daily 150 mg/kg of b.w.) on liver morphology and some biochemical parameters (triacylglycerols, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, bile acids, proteins, albumins and cholinesterase). NAC significantly decreased levels of bile acids and bilirubin in plasma and triacylglycerols in liver, all of them elevated by impairment with CCl4. Reduction of cholesterol induced by CCl4 was completely recovered in the presence of NAC as indicated by its elevation to control levels. NAC administration did not improve the histological parameters. Together with protective effects of NAC, we found also its deleterious properties: parallel administration of CCl4 and NAC increased triacylglycerols, ALT and AST activity and significantly increased plasma cholinesterase activity. We have observed nonsignificantly increased percentage of liver tissue fibrosis. Our results have shown that NAC administered simultaneously with liver damaging agent CCl4, exhibits not only protective, but also deleterious effects as indicated by several biochemical parameters.

Effects of urban coarse particles inhalation on oxidative and inflammatory parameters in the mouse lung and colon

BackgroundAir pollution is a recognized aggravating factor for pulmonary diseases and has notably deleterious effects on asthma, bronchitis and pneumonia. Recent studies suggest that air pollution may also cause adverse effects in the gastrointestinal tract. Accumulating experimental evidence shows that immune responses in the pulmonary and intestinal mucosae are closely interrelated, and that gut-lung crosstalk controls pathophysiological processes such as responses to cigarette smoke and influenza virus infection. Our first aim was to collect urban coarse particulate matter (PM) and to characterize them for elemental content, gastric bioaccessibility, and oxidative potential; our second aim was to determine the short-term effects of urban coarse PM inhalation on pulmonary and colonic mucosae in mice, and to test the hypothesis that the well-known antioxidant N-acetyl-L-cysteine (NAC) reverses the effects of PM inhalation.ResultsThe collected PM had classical features of urban particles and possessed oxidative potential partly attributable to their metal fraction. Bioaccessibility study confirmed the high solubility of some metals at the gastric level. Male mice were exposed to urban coarse PM in a ventilated inhalation chamber for 15 days at a concentration relevant to episodic elevation peak of air pollution. Coarse PM inhalation induced systemic oxidative stress, recruited immune cells to the lung, and increased cytokine levels in the lung and colon. Concomitant oral administration of NAC reversed all the observed effects relative to the inhalation of coarse PM.ConclusionsCoarse PM-induced low-grade inflammation in the lung and colon is mediated by oxidative stress and deserves more investigation as potentiating factor for inflammatory diseases.

Inhibition of Methylglyoxal-Induced AGEs/RAGE Expression Contributes to Dermal Protection by N-Acetyl-L-Cysteine

Background/Aim: Accumulation of advanced glycation end products (AGEs) is a major cause of diabetes mellitus (DM) skin complications. Methylglyoxal (MGO), a reactive dicarbonyl compound, is a crucial intermediate of AGEs generation. N-acetyl-L-cysteine (NAC), an active ingredient of some medicines, can induce endogenous GSH and hydrogen sulfide generation, and set off a condensation reaction with MGO. However, there is rare evidence to show NAC can alleviate DM-induced skin injury through inhibition of AGEs generation or toxicity. The present study aimed to observe the effects of NAC on MGO-induced inflammatory injury and investigate the roles of AGEs and its receptor (RAGE) in NAC’s dermal protection in human HaCaT keratinocytes. Methods: The cells were exposed to MGO to simulate a high MGO status in diabetic blood or tissues. The content of AGEs in serum or cell medium was measured with ELISA. The protective effects of NAC against MGO-induce injury were evaluated by administration before MGO one hour, in virtue of cell viability, mitochondrial membrane potential, inflammation reaction, nuclear factor (NF)-κB activation, matrix metalloproteinase (MMP)-9 expression, as well as cellular behavioral function. Results: We found the AGEs levels of patients with DM were elevated comparing with healthy volunteers. The in vitro AGEs generation was also able to be enhanced by the exposure of HaCaT cells to MGO, which reduced dose-dependently cellular viability, damaged mitochondrial function, triggered secretion of interleukin (IL)-6 and IL-8, activated NF-κB and upregulated MMP-9 expression. Furthermore, the exposure caused cellular adhesion and migration dysfunction, as well as collagen type I inhibition. Importantly, before the exposure to MGO, the preconditioning with NAC significantly attenuated MGO-induced AGEs generation, improved cellular viability and mitochondrial function, partially reversed the overexpression of proinflammatory factors and MMP-9, as well as the activation of NF-κB. Lastly, NAC blocked MGO-induced RAGE upregulation, and inhibition of RAGE with its neutralizing antibody significantly alleviated MGO-induced NF-κB activation, MMP-9 upregulation and inflammatory injury in HaCaT cells. Conclusion: The present work indicates the administration of NAC can prevent MGO-induced dermal inflammatory injury through inhibition of AGEs/RAGE signal, which may provide a basal support for the treatment of diabetic skin complications with NAC-containing medicines in the future.

Antioxidants Attenuate Acute and Chronic Itch: Peripheral and Central Mechanisms of Oxidative Stress in Pruritus.

Itch (pruritus) is one of the most disabling syndromes in patients suffering from skin, liver, or kidney diseases. Our previous study highlighted a key role of oxidative stress in acute itch. Here, we evaluated the effects of antioxidants in mouse models of acute and chronic itch and explored the potential mechanisms. The effects of systemic administration of the antioxidants N-acetyl-L-cysteine (NAC) and N-tert-butyl-α-phenylnitrone (PBN) were determined by behavioral tests in mouse models of acute itch induced by compound 48/80 or chloroquine, and chronic itch by treatment with a mixture of acetone-diethyl-ether-water. We found that systemic administration of NAC or PBN significantly alleviated compound 48/80- and chloroquine-induced acute itch in a dose-dependent manner, attenuated dry skin-induced chronic itch, and suppressed oxidative stress in the affected skin. Antioxidants significantly decreased the accumulation of intracellular reactive oxygen species directly induced by compound 48/80 and chloroquine in the cultured dorsal root ganglia-derived cell line ND7-23. Finally, the antioxidants remarkably inhibited the compound 48/80-induced phosphorylation of extracellular signal-regulated kinase in the spinal cord. These results indicated that oxidative stress plays a critical role in acute and chronic itch in the periphery and spinal cord and antioxidant treatment may be a promising strategy for anti-itch therapy.

Quantitative Analysis of Small Molecular Weight Thiols and Disulfides in Blood from a Sickle Cell Disease Patient Infused with N-Acetyl-L-Cysteine

N-acetyl-L-cysteine (NAC) is an FDA approved drug used to treat acetaminophen overdose or as a mucolytic agent in respiratory disorders. The commonly accepted mechanism of action is that NAC undergoes deacetylation to cysteine, which is then used to synthesize glutathione (GSH), a major intracellular antioxidant. Like other thiol-containing compounds, NAC can also act as a reducing agent to break protein disulfide bonds or as a scavenger of reactive oxygen species. Due to its antioxidant properties, NAC has been proposed as a potential treatment for many diseases associated with oxidative stress, including sickle cell disease (SCD), neurological disorders, infectious diseases, and cancers. Though NAC has been widely studied, a full understanding of the mechanism by which NAC is effective in vivo has been limited by challenges in accurately quantifying NAC and its metabolites.As part of a clinical trial of NAC therapy in SCD, we have developed a liquid chromatography-mass spectrometry (LC-MS) based assay to quantify small molecule free thiols and disulfides using isotopically labeled internal standards. We applied this method to quantify small molecular thiols and disulfides in whole blood, red blood cells, and plasma from a SCD patient before (pre) and at 1, 8, 24 and 72 hr time points of intravenous administration of NAC at a dose of 300 mg/kg (a bolus infusion of 150 mg/kg for 1 hour followed by 150 mg/kg given over the next 7 hr). The cysteine concentration in whole blood increased to 286 μM at 1 hr from 97 μM at baseline, indicating that NAC is indeed rapidly metabolized (deacetylated) to cysteine. Interestingly, although cysteine concentration in RBCs increased over 4 fold at 1 hr and remained high compared to baseline, the highest concentration of total GSH in blood was observed at 24 hr (743 μM compared to 494 μM at baseline). Intracellular availability of cysteine is known as a rate-limiting step for GSH synthesis, and the delayed accumulation of GSH may suggest that NAC is involved in the extracellular deficit of reducing equivalents before it serves as a substrate in GSH synthesis.To explore this possibility, we quantitated NAC and its oxidation products, homo- and mixed disulfides. We found that total NAC concentration reached 1.58 mM in whole blood at 1 hr, but 44% of NAC was oxidized to N-acetyl-cystine (NAC-ss) or formed mixed disulfides with GSH (GS-ss-NAC) and Cys (Cys-ss-NAC), whereas the NAC used for infusion contained less than 0.5% in the oxidized form (NAC-ss). Concurrent with the formation of NAC disulfides, the levels of oxidized GSH (GSSG, GS-ss-Cys) and cysteine (cystine) were significantly decreased. These observations suggest that NAC administration of SCD not only increases GSH levels by raising the cysteine concentration, but also directly functions as an antioxidant to reduce oxidative stress. SCD patients are known to have low levels of GSH and frequently experience oxidative stress. NAC treatment is likely to address both issues. We plan to analyze the effects of NAC on blood small molecule thiol concentrations in several more SCD patients. DisclosuresNo relevant conflicts of interest to declare.

Immunohistopathological changes in murine Schistosomiasis mansoni under the influence of N-acetyl-L-cysteine

The main pathology associated with Schistosomiasis mansoni is granulomatous inflammation that may develop into hepatosplenic disease with fibrosis and hepatoesplenomegaly. It is known that N-acetyl-L-cysteine (NAC) reduces tissue damage in chronic liver diseases owing to its anti-inflammatory, antioxidant, and detoxifying properties. In this study, we investigated the imunohistopathological changes in murine schistosomiasis mansoni under the influence of NAC, in combination with Praziquantel (PZQ) or not. Three groups of mice were formed to evaluate the effects of NAC during infection in the acute, intermediate, and chronic phases. Each group was further subdivided into four subgroups: NAC, PZQ, NAC + PZQ and control (without treatment). Oral administration of NAC (200 mg/kg/day) was carried out on the first day after infection for the acute phase and on the 45th for the intermediate and chronic phases for 59 and 45, 75 days, respectively. PZQ (100 mg/kg/day), was given orally by gavage from the 45th to 49th day after infection. Histopathological analysis of liver tissue provided evidence that combined NAC + PZQ treatment reduced the development of granulomas observed in the chronic phase. Animals treated with NAC and/or PZQ showed a reduction in the size of granulomas and all those treated with NAC exhibited a lower degree of fibrosis. In all groups, NAC decreased the synthesis of interferon-γ and nitric oxide, while increasing the levels of interleukin-10, but it did not influence the production of interleukin-4. On the whole, NAC treatment induced an immunomodulatory effect and reduced liver damage during the granulomatous inflammation in S. mansoni-infected mice.

Apoptosis induction of U937 human leukemia cells by diallyl trisulfide induces through generation of reactive oxygen species

BackgroundDiallyl trisulfide (DATS) is one of the major constituents in garlic oil and has demonstrated various pharmacological activities, including antimicrobial, antihyperlipidemic, antithrombotic, and anticancer effects. However, the mechanisms of antiproliferative activity in leukemia cells are not fully understood. In this study, the apoptotic effects of DATS were investigated in human leukemia cells.ResultsResults of this study indicated that treatment with DATS resulted in significantly inhibited leukemia cell growth in a concentration- and time-dependent manner by induction of apoptosis. In U937 cells, DATS-induced apoptosis was correlated with down-regulation of Bcl-2, XIAP, and cIAP-1 protein levels, cleavage of Bid proteins, activation of caspases, and collapse of mitochondrial membrane potential. The data further demonstrated that DATS increased intracellular reactive oxygen species (ROS) generation, which was attenuated by pretreatment with antioxidant N-acetyl-l-cysteine (NAC), a scavenger of ROS. In addition, administration of NAC resulted in significant inhibition of DATS-induced apoptosis by inhibiting activation of caspases.ConclusionsThe present study reveals that the cytotoxicity caused by DATS is mediated by generation of ROS and subsequent activation of the ROS-dependent caspase pathway in U937 leukemia cells.

The cystine–glutamate transporter enhancer N-acetyl-l-cysteine attenuates cocaine-induced changes in striatal dopamine but not self-administration in squirrel monkeys

Extrasynaptic glutamate has been shown to regulate dopamine function in the mesocorticolimbic pathway, which plays an important role in the behavioral pharmacology of psychostimulants. Basal levels of glutamate are primarily regulated by the cystine–glutamate transporter and provide glutamatergic tone on extrasynaptic glutamate receptors. The present study examined the effects of a cystine–glutamate transporter enhancer on the neurochemical and behavioral effects of cocaine and amphetamine in nonhuman primates. It was hypothesized that augmenting extrasynaptic glutamate release with N-acetyl-l-cysteine (NAC), a cystine prodrug, would attenuate cocaine- or amphetamine-induced increases in extracellular dopamine and their corresponding behavioral-stimulant and reinforcing effects. In vivo microdialysis was used to evaluate cocaine-induced changes in extracellular dopamine (DA) in the caudate nucleus (n=3). NAC significantly attenuated cocaine-induced increases in dopamine but had inconsistent effects on amphetamine-induced increases in dopamine (n=4). Separate groups of subjects were either trained on a fixed-interval schedule of stimulus termination (n=6) or on a second-order schedule of self-administration (n=5) to characterize the behavioral-stimulant and reinforcing effects of psychostimulants, respectively. Systemic administration of NAC did not alter the behavioral-stimulant effects of either cocaine or amphetamine. Furthermore, cocaine self-administration and reinstatement of previously extinguished cocaine self-administration were not altered by pretreatment with NAC. Hence, drug interactions on caudate neurochemistry in vivo were not reflected in behavioral measures in squirrel monkeys. The present results in nonhuman primates do not support the use of NAC as a pharmacotherapy for cocaine abuse, although rodent and clinical studies suggest otherwise.