NAC Supplementation Research Articles

Role of Oxidative Stress on Insulin Resistance in Diet-Induced Obesity Mice.

Insulin resistance is the link between obesity and type 2 diabetes mellitus. The molecular mechanism by which obese individuals develop insulin resistance has not yet been fully elucidated; however, inconclusive and contradictory studies have shown that oxidative stress may be involved in the process. Thus, this study aimed to evaluate the effect of reactive species on the mechanism of insulin resistance in diet-induced obese mice. Obese insulin-resistant mice were treated with N-acetylcysteine (NAC; 50 mg/kg per day, for 15 days) by means of oral gavage. Twenty-four hours after the last NAC administration, the animals were euthanized and their tissues were extracted for biochemical and molecular analyses. NAC supplementation induced improved insulin resistance and fasting glycemia, without modifications in food intake, body weight, and adiposity. Obese mice showed increased dichlorofluorescein (DCF) oxidation, reduced catalase (CAT) activity, and reduced glutathione levels (GSH). However, treatment with NAC increased GSH and CAT activity and reduced DCF oxidation. The gastrocnemius muscle of obese mice showed an increase in nuclear factor kappa B (NFκB) and protein tyrosine phosphatase (PTP1B) levels, as well as c-Jun N-terminal kinase (JNK) phosphorylation compared to the control group; however, NAC treatment reversed these changes. Considering the molecules involved in insulin signaling, there was a reduction in insulin receptor substrate (IRS) and protein kinase B (Akt) phosphorylation. However, NAC administration increased IRS and Akt phosphorylation and IRS/PI3k (phosphoinositide 3-kinase) association. The results demonstrated that oxidative stress-associated obesity could be a mechanism involved in insulin resistance, at least in this animal model.

Effects of supplementation of sodium acetate on rumen fermentation and microbiota in postpartum dairy cows.

The primary product of rumen fermentation is acetic acid, and its sodium salt is an excellent energy source for post-partum cows to manage negative energy balance (NEB). However, it is unknown how adding sodium acetate (NAc) may affect the rumen bacterial population of post-partum cows. Using the identical nutritional total mixed ration (TMR), this research sought to characterize the impact of NAc supplementation on rumen fermentation and the composition of bacterial communities in post-partum cows. After calving, 24 cows were randomly assigned to two groups of 12 cows each: a control group (CON) and a NAc group (ACE). All cows were fed the same basal TMR with 468 g/d NaCl added to the TMR for the CON group and 656 g/d NAc added to the TMR for the ACE group for 21 days after calving. Ruminal fluid was collected before morning feeding on the last day of the feeding period and analyzed for rumen bacterial community composition by 16S rRNA gene sequencing. Under the identical TMR diet conditions, NAc supplementation did not change rumen pH but increased ammonia nitrogen (NH3-N) levels and microbial crude protein (MCP) concentrations. The administration of NAc to the feed upregulated rumen concentrations of total volatile fatty acids (TVFA), acetic, propionic, isovaleric and isobutyric acids without affecting the molar ratio of VFAs. In the two experimental groups, the Bacteroidota, Firmicutes, Patescibacteria and Proteobacteria were the dominant rumen phylum, and Prevotella was the dominant rumen genus. The administration of NAc had no significant influence on the α-diversity of the rumen bacterial community but upregulated the relative abundance of Prevotella and downregulated the relative abundance of RF39 and Clostridia_UCG_014. In conclusion, the NAc supplementation in the post-peripartum period altered rumen flora structure and thus improved rumen fermentation in dairy cows. Our findings provide a reference for the addition of sodium acetate to alleviate NEB in cows during the late perinatal period.

The possible protective role of N-acetyl cysteine on duodenal mucosa of high fat diet and orlistat treated adult male albino rats and the active role of tumor necrosis factor α (TNFα) and Interleukin 6 (IL6) (histological and biochemical study)

ABSTRACT Background Obesity is a major universal health issue linked to a majority of illness. Aim To evaluate the histological and biochemical changes occurred in the duodenal mucosa of high fat diet HFD and orlistat fed rats and to assess the possible protective role of N-acetyl cysteine NAC supplementation. Material and method Sixty male albino rats weighing 180–200 g were classified randomly into control group I and three experimental groups (HFD group II, HFD + orlistat group III, and HFD + orlistat + NAC group IV). All experimental groups received HFD alone/and treatment for 6 weeks. Group III received orlistat (32 mg/kg/day) before meals and group IV received the same regimen as group III in addition to NAC (230 mg/kg/day) after meals. After completion of the experiment, duodenal sections were processed for histological examination, oxidative stress parameters, and semiqualitative real time PCR for proinflammatory mediators TNFα and IL6 evaluation. Also, plasma lipid parameters were assessed and morphometric duodenal results were analyzed statistically. Results By histological examination of HFD and (HFD + orlistat) groups, we found severe to moderate duodenal structural disturbances, increased goblet cells, collagen fibers, and BAX and iNOS immunostaining. By Biochemical examination, both groups showed increased proinflammatory markers level (TNFα and IL6) with decreased all antioxidant parameters and increased MDA. Moreover, NAC treatment in group IV significantly reduced all structural changes, levels of proinflammatory mediators and increased all antioxidant parameter levels and decreased MDA. Conclusion All findings elucidated that NAC could be accounted to be a useful drug for protection of duodenal mucosa of HFD and orlistat treated animals.

Site-specific protein modification by 3-n-butylphthalide in primary hepatocytes: Covalent protein adducts diminished by glutathione and N-acetylcysteine

Aims3-n-Butylphthalide (NBP) is widely used for the treatment of cerebral ischaemic stroke but can causeliver injury in clinical practice. This study aims to elucidate the underlying mechanisms and propose potential preventive strategies. Main methodsNBP and its four major metabolites, 3-hydroxy-NBP (3-OH-NBP), 10-hydroxy-NBP, 10-keto-NBP and NBP-11-oic acid, were synthesized and evaluated in primary human or rat hepatocytes (PHHs, PRHs). NBP-related substances or amino acid adducts were identified and semi-quantitated by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). The target proteins and binding sites were identified by shotgun proteomics based on peptide mass fingerprinting coupled with tandem mass spectrometry and verified by molecular docking. Key findingsThe toxicity of NBP and its four major metabolites were compared in both PHHs and PRHs, and 3-OH-NBP was found to be the most toxic metabolite. 3-OH-NBP induced remarkable cell death and oxidative stresses in hepatocytes, which correlated well with the levels of glutathione and N-acetylcysteine adducts (3-GSH-NBP and 3-NAC-NBP) in cell supernatants. Additionally, 3-OH-NBP covalently conjugated with intracellular Cys, Lys and Ser, with preferable binding to Cys sites at Myh9 Cys1380, Prdx4 Cys53, Vdac2 Cys48 and Vdac3 Cys36. Furthermore, we found that CYP3A4 induction by rifampicin augmented NBP-induced cell toxicity and supplementing with GSH or NAC alleviated the oxidative stresses and reactive metabolites caused by 3-OH-NBP. SignificanceOur work suggests that glutathione depletion, mitochondrial injury and covalent protein modification are the main causes of NBP-induced hepatotoxicity, which may be prevented by exogenous GSH or NAC supplementation and avoiding concomitant use of CYP3A4 inducers.

α-Lipoik asit ve N-asetilsisteinin sıçan karaciğerinde dietilnitrozamin ve yüksek yağlı diyetin neden olduğu oksidatif stres ve preneoplastik lezyonlar üzerine etkisi

Aim: Oxidative stress and inflammation are important for development of nonalcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). High fat diet (HFD) acts as promoter and induces cancer formation by diethylnitrosamine (DEN)-initiated carcinogenesis. DEN+HFD experimental model may be suitable to investigate the relationship between diet, cirrhosis and cancer.
 Methods: Rats were injected with DEN (50 mg/kg/once a week; i.p.) for 4 weeks. After 15 days, rats received HFD with/without supplementations of α-lipoic acid (ALA; 2 g/kg chow), N-acetylcysteine (NAC; 1% w/v drinking water) and their combination for 12 weeks. 
 Results: DEN+HFD-treatment resulted in increase of serum hepatic damage markers, hepatic oxidative stress parameters (lipid/protein oxidation products) and fibrotic changes. However, no HCC nodule was detected. Hepatic GST-pi and Ki-67 expressions also increased. Accordingly, DEN+HFD-treatment resulted in precancerous lesions and high rate of proliferation in the liver. NAC supplementation decreased hepatic oxidative stress and formation of fibrotic and preneoplastic lesions of DEN+HFD-treated rats. However, ALA supplementation did not have a curative effect on these lesions. No synergistic effect was seen with co-administration of ALA and NAC.
 Conclusions: According to present results NAC, acting as an antioxidant, has ameliorating effect on DEN+HFD-induced oxidative stress and the formation of preneoplastic lesions in liver.

N-acetyl-l-cysteine mediated regulation of DNA fragmentation, an apoptotic event, against methoxychlor toxicity in the granulosa cells of ovarian antral follicles

Methoxychlor (MXC), an organo-chlorine insecticide, is a reproductive toxicant in females, causing apoptosis-mediated follicular atresia. To elucidate the potentials of Methoxychlor as a geno-toxicant, granulosa cells of healthy antral follicles, exposed to MXC and antioxidant, N-acetyl-l-cysteine, were studied by the terminal deoxynucleotidyltransferase-dUTP nick end-labelling and single-cell gel electrophoresis (comet) assays.MXC caused DNA fragmentation, as revealed by the increased incidence of dark brown condensed TUNEL positive cells in contrast with lightly brown TUNEL negative cells with maximum TUNEL positive cells were observed in 100 μg/mL MXC treated groups. Quantitatively, maximum geno-toxicity was exhibited at highest MXC treatment with percent tail DNA as 17.87 ± 0.85, 41.16 ± 3.94, and 47.73 ± 3.71 in comparison with control (0.65 ± 0.03, 2.91 ± 0.27, and 7.16 ± 1.39) after 24, 48 and 72 h exposure duration, respectively. MXC treated groups exhibited Type 1-Type 3 comets as compared to Type 0 comets in control groups. Supplementation of NAC led to significant (p < 0.05) decline in geno-toxicity in MXC treated groups with maximum amelioration observed at 5 and 10 mM.Consequently, increased DNA damage attributed to the granulosa cells apoptosis in response to Methoxychlor exposure was significantly combated by NAC supplementation, preventing the geno-toxicity induced cyto-toxicity in GCs.

N-Acetylcysteine Reduces Skeletal Muscles Oxidative Stress and Improves Grip Strength in Dysferlin-Deficient Bla/J Mice.

Dysferlinopathy is an autosomal recessive muscular dystrophy resulting from mutations in the dysferlin gene. Absence of dysferlin in the sarcolemma and progressive muscle wasting are hallmarks of this disease. Signs of oxidative stress have been observed in skeletal muscles of dysferlinopathy patients, as well as in dysferlin-deficient mice. However, the contribution of the redox imbalance to this pathology and the efficacy of antioxidant therapy remain unclear. Here, we evaluated the effect of 10 weeks diet supplementation with the antioxidant agent N-acetylcysteine (NAC, 1%) on measurements of oxidative damage, antioxidant enzymes, grip strength and body mass in 6 months-old dysferlin-deficient Bla/J mice and wild-type (WT) C57 BL/6 mice. We found that quadriceps and gastrocnemius muscles of Bla/J mice exhibit high levels of lipid peroxidation, protein carbonyls and superoxide dismutase and catalase activities, which were significantly reduced by NAC supplementation. By using the Kondziela’s inverted screen test, we further demonstrated that NAC improved grip strength in dysferlin deficient animals, as compared with non-treated Bla/J mice, without affecting body mass. Together, these results indicate that this antioxidant agent improves skeletal muscle oxidative balance, as well as muscle strength and/or resistance to fatigue in dysferlin-deficient animals.

PSIV-B-41 Late-Breaking: The effect of TP, ALC and NAC cocktail on the oxidation-reduction system of mouse early embryo during in vitro culture

Abstract During in vitro culture, the growth environment of embryos cannot be completely simulated as an in vivo, because the embryos are exposed to oxidative stress (OS) for a long time. However, the supplementation of antioxidants to the culture medium is undoubtedly the most effective method to reduce OS. Previous Studies have shown that TP, ALC and NAC alone have antioxidant effects on OS embryos during different stages of the oxidation-reduction reaction system respectively. Therefore in the current study we used TP, ALC and NAC in combination to improve the quality of early mice embryo and its effects on the embryo endogenous oxidation-reduction reaction system, to minimize the obstacles in the process of in vitro embryo during oxidative stress. The expression of endogenous genes in embryos was detected by RT-PCR, and the ROS and GSH levels in embryos were determined by DCHFDA and CMF2HC staining respectively. The combine supplementation of TP, ALC and NAC significantly up-regulate the expression of oxidase genes (NOX1, NOX2, NOX4, Duox1 and Duox2) in embryo, and effectively promote the expression of antioxidant enzymes genes (SOD1,SOD2,CAT, GPx1,GPx2 and GPx4) in the embryo. In addition, the supplementation of TP, ALC and NAC also up-regulated the expression of Nrf2 gene in embryo (P ﹤ 0.01）as compare to other groups. Moreover the addition of TP, ALC and NAC to embryo culture medium significantly decreased the ROS level (P ﹤ 0.01）and increased the GSH level (P ﹤ 0.01）as compare to control and other treated groups. In conclusion the present study shows that the supplementation of TP, ALC and NAC cocktail can promote the early mouse embryo development, effectively upregulate GSH and down-regulate the ROS level in early mouse embryo during IVC. Moreover it up-regulate the expression of oxidase and antioxidant enzymes and Nrf2 genes.

N-Acetyl cysteine does not improve repeated intense endurance cycling performance of well-trained cyclists

To evaluate the effect of antioxidant supplementation on intense endurance exercise performance and the physiologic exercise response acutely and in early recovery. Well-trained cyclists (n = 11, peak VO2: 69 ± 7ml/min/kg) completed two identical standardized 20-min warm-up periods (WU-1 and WU-2) prior to two performance tests (PT) with a duration of ~ 4min representing a qualifying (PT-1) and final race (PT-2) on the same day separated by 90min. Subjects were supplemented orally with placebo (PLA) and N-acetyl cysteine (NAC; 20mg/kg) before exercise in a double-blinded crossover design. Mean power during PT-1 did not differ (P = 0.39) between PLA (400 ± 44W) and NAC (401 ± 44W) as was the case during PT-2 with similar performance (P = 0.74) between PLA (401 ± 43W) and NAC (400 ± 42W). Subjective "readiness" was lowered by prior exhaustive exercise from PT-1 to PT-2 (P = 0.012) in both PLA and NAC. Plasma total antioxidant capacity was not affected by supplementation and prior exhaustive exercise (respective main effects: P = 0.83 and P = 0.19) which also was observed for peak VO2 at ~ 5L/min (P = 0.84 and P = 0.30). In WU-1 and WU-2, both cycling economy at ~ 20% (P = 0.10 and P = 0.21) and plasma potassium at ~ 5mmol/L (P = 0.46 and P = 0.26) were unaffected by supplementation and prior exercise. Athletes executing maximal efforts of a ~ 4-min duration twice daily, as seen in track cycling, appear to gain no benefit from oral NAC supplementation on acute and subsequent performance following short-term recovery. Moreover, well-trained cyclists exhibit rapid recovery from a single bout of intense endurance cycling.

N-Acetyl-cysteine mediated inhibition of spermatogonial cells apoptosis against malathion exposure in testicular tissue.

Toxicological studies so far suggest that excessive use of malathion, an organophosphate insecticide, causes serious ill-effects in mammalian reproductive physiology. The present study aims at assessing malathion-induced toxicity in a dose- and time-dependent manner with mitigating effects of N-acetyl-l-cysteine. The testicular germ cell viability was monitored using MTT assay, where NAC, being an antioxidant significantly reduced malathion-induced toxicity by enhancing the frequency of cell viability. The histomorphological analysis showed that NAC successfully diminished several apoptotic features in testicular cells, induced by malathion. The differential EB/AO staining revealed a significant decline in the percentage of apoptosis after NAC supplementation. NAC also diminished the malathion-induced DNA fragmentation along with significantly reduction in oxidative stress parameters causing decrease in lipid peroxidation and enhancement of ferric reducing antioxidant power within testicular germ cells. Thus, NAC mitigated the malathion-induced toxicity, proving its potential in infertility treatment.

BMI-1 Mediates Estrogen-Deficiency-Induced Bone Loss by Inhibiting Reactive Oxygen Species Accumulation and T Cell Activation.

Previous studies have shown that estrogen regulates bone homeostasis through regulatory effects on oxidative stress. However, it is unclear how estrogen deficiency triggers reactive oxygen species (ROS) accumulation. Recent studies provide evidence that the B lymphoma Mo-MLV insertion region 1 (BMI-1) plays a critical role in protection against oxidative stress and that this gene is directly regulated by estrogen via estrogen receptor (ER) at the transcriptional level. In this study, ovariectomized mice were given drinking water with/without antioxidant N-acetyl-cysteine (NAC, 1 mg/mL) supplementation, and compared with each other and with sham mice. Results showed that ovariectomy resulted in bone loss with increased osteoclast surface, increased ROS levels, T cell activation, and increased TNF and RANKL levels in serum and in CD4 T cells; NAC supplementation largely prevented these alterations. BMI-1 expression levels were dramatically downregulated in CD4 T cells from ovariectomized mice. We supplemented drinking water to BMI-1-deficient mice with/without NAC and compared them with each other and with wild-type (WT) mice. We found that BMI-1 deficiency mimicked alterations observed in ovariectomy whereas NAC supplementation reversed all alterations induced by BMI-1 deficiency. Because T cells are critical in mediating ovariectomy-induced bone loss, we further assessed whether BMI-1 overexpression in lymphocytes can protect against estrogen deficiency-induced osteoclastogenesis and bone loss by inhibiting oxidative stress, T cell activation, and RANKL production. When WT and Eμ-BMI-1 transgenic mice with BMI-1 specifically overexpressed in lymphocytes were ovariectomized and compared with each other and with WT sham mice, we found that BMI-1 overexpression in lymphocytes clearly reversed all alterations induced by ovariectomy. Results from this study indicate that estrogen deficiency downregulates BMI-1 and subsequently increases ROS, T cell activation, and RANKL production in T cells, thus enhancing osteoclastogenesis and accelerating bone loss. This study clarifies a novel mechanism regulating estrogen deficiency-induced bone loss. © 2016 American Society for Bone and Mineral Research.

TIGAR contributes to ischemic tolerance induced by cerebral preconditioning through scavenging of reactive oxygen species and inhibition of apoptosis.

Previous study showed that TIGAR (TP53-induced glycolysis and apoptosis regulator) protected ischemic brain injury via enhancing pentose phosphate pathway (PPP) flux and preserving mitochondria function. This study was aimed to study the role of TIGAR in cerebral preconditioning. The ischemic preconditioning (IPC) and isoflurane preconditioning (ISO) models were established in primary cultured cortical neurons and in mice. Both IPC and ISO increased TIGAR expression in cortical neurons. Preconditioning might upregulate TIGAR through SP1 transcription factor. Lentivirus mediated knockdown of TIGAR significantly abolished the ischemic tolerance induced by IPC and ISO. ISO also increased TIGAR in mouse cortex and hippocampus and alleviated subsequent brain ischemia-reperfusion injury, while the ischemic tolerance induced by ISO was eliminated with TIGAR knockdown in mouse brain. ISO increased the production of NADPH and glutathione (GSH), and scavenged reactive oxygen species (ROS), while TIGAR knockdown decreased GSH and NADPH production and increased the level of ROS. Supplementation of ROS scavenger NAC and PPP product NADPH effectively rescue the neuronal injury caused by TIGAR deficiency. Notably, TIGAR knockdown inhibited ISO-induced anti-apoptotic effects in cortical neurons. These results suggest that TIGAR participates in the cerebral preconditioning through reduction of ROS and subsequent cell apoptosis.

N-ACYTEL CYSTEINE AMELIORATES METHOTREXATE INDUCED HEPATIC TOXICITY AND GENOTOXICITY IN MALE ALBINO RATS

Background: Methotrexate (MTX) is widely used as a cytotoxic chemotherapeutic agent for malignancies as well as in the treatment of various inflammatory diseases. MTX treatment has been associated with hepatic toxicity and genotoxicity. The current study was conducted to assess the potential protective role of N-acetylcysteine in attenuation of methotrexate–induced hepatic damage and genotoxicity in MTX intoxicated male albino rats. Methods: Forty, apparently healthy adult male albino rats weighed 150+10 gm were randomly divided into four groups; [group 1: negative control group, group 2: positive control (NAC treated) group, group 3: MTX treated group, group 4: MTX/NAC treated group]. The rats were treated once daily for 12 weeks by I.V injection of Methotrexate in a dose of 2 mg/kg (1 /7 LD50) and N-acetylcysteine in a dose of 80 mg/kg (1 /14 LD50) in the tail veins of rats. Blood samples were obtained at the end of the 4th, 8th and 12th weeks and were prepared for ALT levels and BAX gene expression value examination. At the end of the study, liver samples were obtained for histopathological examination. Results: A significant constant increase in ALT levels and BAX gene expression value of the MTX-treated group (group 3) was observed throughout the study. Supplementation of NAC concomitantly with MTX in group 4 reduced significantly ALT levels and BAX gene expression value when compared to the non-supplemented group 3 that treated with MTX at the 4th, 8th and 12th weeks (P< 0.000).The previous chemical results were confirmed by the histopathological studies of the liver that revealed the presence of dilatation and congestion of the central veins, hepatic sinusoids, hepatic arteries, portal veins with increased number of Kupffer cells and pyknosis of the hepatic nuclei in group 3: MTX treated group. On the other hand, the liver sections showed the normal hepatic architectures with addition of NAC with MTX in group 4. Conclusion: The present study showed that NAC has a good protective effect against the hepatic damage and genotoxicity induced by MTX in male albino rats.

COMPARATIVE STUDY OF THE PROTECTIVE EFFECT OF N-ACYTEL CYSTEINE AND MELATONIN ON METHOTREXATE INDUCED RENAL TOXICITY IN MALES ALBINO RATS

Background: Methotrexate (MTX) is widely used as a cytotoxic chemotherapeutic agent for malignancies as well as in the treatment of various inflammatory diseases. MTX treatment has been associated with renal toxicity. The current study was conducted to assess the potential protective role of N-acetylcysteine and/or melatonin in attenuation of methotrexate–induced renal damage in MTX intoxicated male albino rats. Methods: sixty, apparently healthy adult male albino rats weighed 150+10 gm were randomly divided into six groups; (group 1: negative control group, group 2: positive control (NAC treated) group, group 3: positive control (Melatonin treated) group, group 4: MTX treated group, group 5: MTX/NAC treated group, group 6: MTX/Melatonin treated group). The rats were treated once daily for 12 weeks by I.V injection of Methotrexate in a dose of 2 mg/kg (1 /7 LD50), N-acetylcysteine in a dose of 80 mg/kg (1 /14 LD50) and Melatonin: in a daily dose of 10 mg/kg (1 /36 LD50) in the tail veins of rats and blood samples were obtained at the end of the 4th, 8th and 12th weeks and were prepared for Creatinine examination. At the end of the study, kidney samples were obtained for histopathological examination. Results: A significant constant increase in the creatinine of the MTX-treated group (group 4) was observed throughout the study. Supplementation of NAC concomitantly with MTX in group 5 reduced significantly creatinine when compared to the non-supplemented group 4 that treated with MTX at the 4th, 8th and 12th weeks. On the other hand, the use of the melatonin in combination with MTX in group 6 produced minimal non-significant reduction of the creatinine level relative to group 4 at the 4th, 8th and 12th weeks (P>0.05). The previous chemical results were confirmed by the histopathological studies of the kidney that revealed maximal affection of the renal cortex in the MTX-treated rats (group 4). Kidney histopathologic findings were significantly milder when NAC was co-administered with MTX in groups 5. Meanwhile, deterioration of the renal cortical structure was observed in the MTX – melatonin treated rats (group 6). Conclusion: The present study showed that NAC has a superior protective effect than Melatonin against the renal damage induced by MTX in male albino rats.

N-acetylcysteine Protects Mice from High Fat Diet-induced Metabolic Disorders.

To study the effects of N-acetylcysteine (NAC, C5H9NO3S) on diet-induced obesity and obesity-related metabolic disorders. Six-week-old male C57BL/6 mice fed a chow or high-fat diet (HFD) were treated with NAC (2g/L) in drinking water for 11weeks. Its influences on body weight and food intake were manually measured, and influence on body composition were analyzed by magnetic residence imaging. Glucose meter and ELISA were used to determine serum glucose and insulin levels, as well as lipid content in the liver. The effects of NAC treatment on mRNA levels of genes involved in inflammation, thermogenesis, and lipid metabolism in various tissues were determined by real time PCR. NAC supplementation inhibited the increase of fat mass and the development of obesity when mice were fed an HFD. NAC treatment significantly lowered HFD-induced macrophage infiltration, and enhanced adiponectin gene expression, resulting in reduced hyperglycemia and hyperinsulinemia, and improvement of insulin resistance. NAC oral administration suppressed hepatic lipid accumulation, as evidenced by lower levels of triglyceride and cholesterol in the liver. The beneficial effects are associated with a decrease of hepatic Pparγ and its target gene expression, and an increase in the expression of genes responsible for lipid oxidation and activation of farnesoid X receptor. Furthermore, NAC treatment also stimulates expression of thermogenic genes. These results provide direct proof of the protective potential of NAC against HFD-induced obesity and obesity-associated metabolic disorders.

Acute supplementation of N-acetylcysteine does not affect muscle blood flow and oxygenation characteristics during handgrip exercise.

N‐acetylcysteine (NAC; antioxidant and thiol donor) supplementation has improved exercise performance and delayed fatigue, but the underlying mechanisms are unknown. One possibility is NAC supplementation increases limb blood flow during severe‐intensity exercise. The purpose was to determine if NAC supplementation affected exercising arm blood flow and muscle oxygenation characteristics. We hypothesized that NAC would lead to higher limb blood flow and lower muscle deoxygenation characteristics during severe‐intensity exercise. Eight healthy nonendurance trained men (21.8 ± 1.2 years) were recruited and completed two constant power handgrip exercise tests at 80% peak power until exhaustion. Subjects orally consumed either placebo (PLA) or NAC (70 mg/kg) 60 min prior to handgrip exercise. Immediately prior to exercise, venous blood samples were collected for determination of plasma redox balance. Brachial artery blood flow (BABF) was measured via Doppler ultrasound and flexor digitorum superficialis oxygenation characteristics were measured via near‐infrared spectroscopy. Following NAC supplementaiton, plasma cysteine (NAC: 47.2 ± 20.3 μmol/L vs. PLA: 9.6 ± 1.2 μmol/L; P = 0.001) and total cysteine (NAC: 156.2 ± 33.9 μmol/L vs. PLA: 132.2 ± 16.3 μmol/L; P = 0.048) increased. Time to exhaustion was not significantly different (P = 0.55) between NAC (473.0 ± 62.1 sec) and PLA (438.7 ± 58.1 sec). Resting BABF was not different (P = 0.79) with NAC (99.3 ± 31.1 mL/min) and PLA (108.3 ± 46.0 mL/min). BABF was not different (P = 0.42) during exercise or at end‐exercise (NAC: 413 ± 109 mL/min; PLA: 445 ± 147 mL/min). Deoxy‐[hemoglobin+myoglobin] and total‐[hemoglobin+myoglobin] were not significantly different (P = 0.73 and P = 0.54, respectively) at rest or during exercise between conditions. We conclude that acute NAC supplementation does not alter oxygen delivery during exercise in men.

Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine.

Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.

Effect of oral N-acetyl cysteine supplementation in type 2 diabetic patients on intracellular glutathione content and innate immune responses to Burkholderia pseudomallei

Type 2 diabetic patients have increased susceptibility to melioidosis, an infectious disease caused by Burkholderia pseudomallei. We had previously shown that peripheral blood mononuclear cells (PBMCs) from diabetic patients with poor glycemic control had a defective IL-12 and IFNγ response to B. pseudomallei infection, resulting in poor intracellular bacterial control. The impaired IL-12 response was due to glutathione (GSH) deficiency characterized by a low reduced to oxidized glutathione ratio (GSH ratio) and could be restored by the addition of reduced GSH to the infected cells. Our goal is to determine whether N-acetyl cysteine (NAC, a GSH pro-drug) supplementation in diabetic patients could improve their immune control of B. pseudomallei. Type 2 diabetic patients with poor glycemic control were given oral supplementation of NAC for six weeks at 1200 mg daily. Their PBMCs and subsets of immune cells showed a significant increase in free GSH concentration. However, the GSH ratio, IL-12 and IFNγ production, and intracellular bacterial killing upon ex-vivo infection did not improve. Thus, oral NAC supplementation in diabetic patients is sufficient to increase intracellular GSH content in blood cells. However, modulating the free GSH content is not sufficient to improve infection outcome as it is the GSH ratio that regulates the IL-12 response in monocytes.

DietaryN-acetylcysteine supplementation alleviates liver injury in lipopolysaccharide-challenged piglets

The present study was carried out to determine whether N-acetylcysteine (NAC) could modulate liver injury in a lipopolysaccharide (LPS)-challenged piglet model. For this purpose, eighteen piglets were randomly assigned to the control, LPS or NAC group. Piglets in the control and LPS groups were fed a basal diet, whereas those in the NAC group were fed the basal diet supplemented with 500 mg/kg NAC. On days 10, 13 and 20 of the trial, the LPS- and NAC-treated piglets were intraperitoneally administered LPS (100 μg/kg body weight), while the control group was administered the same volume of saline. On day 20 of the trial, blood samples were obtained 3 h after LPS or saline injection. On day 21, the piglets were killed to collect liver samples. Dietary NAC supplementation attenuated LPS-induced liver histomorphological abnormalities. Compared with the control group, in the LPS-challenged piglets, the activities of alanine aminotransferase and aspartate aminotransferase and the concentrations of H2O2, TNF-α, IL-6 and PGE2 were dramatically increased in the plasma and the activity of superoxide dismutase in the plasma and that of glutathione peroxidase in the liver were significantly decreased. The LPS challenge also increased the concentration of AMP and the ratio of AMP:ATP, but decreased adenylate energy charges and the levels of ATP and ADP. These adverse effects of the LPS challenge were ameliorated by NAC supplementation. Moreover, NAC inhibited the LPS-induced increases in the abundance of liver heat shock protein 70 and NF-κB proteins. In conclusion, these results suggest that dietary NAC supplementation alleviates LPS-induced liver injury by reducing the secretion of pro-inflammatory cytokines, increasing the antioxidative capacity and improving energy metabolism.

Plasma glutathione of HIV+ patients responded positively and differently to dietary supplementation with cysteine or glutamine

ObjectivePatients with positivity for the human immunodeficiency virus (HIV+) present low concentrations of antioxidant nutrients, including total glutathione (GSH) and its precursors. We investigated the responses of the sulfur-containing amino acid pathway to cysteine and glutamine (Gln) dietary supplements in patients with HIV+ compared with healthy controls. MethodsTwelve treated patients (six men and six women, 22–45 y old) and 20 healthy controls (10 men and 10 women, 20–59 y old) were randomly assigned to 7-d dietary supplements containing N-acetylcysteine (NAC; 1 g/d) or Gln (20 g/d), with a 7-d washout period ingesting their usual diet. Blood samples were drawn after an overnight fast. High-performance liquid chromatographic plasma analysis of sulfur-containing amino acids (methionine, homocysteine, cysteine, and taurine), GSH, oxidized GSH, and serine, glycine, glutamic acid, and Gln was carried out moments before and after 7-d supplementations. Statistical comparisons were undertaken between groups and between dietary supplements (P < 0.05). ResultsPatients with HIV+ showed higher oxidized GSH and lower concentrations of GSH and all amino acids except homocysteine. The HIV+ group responded to the NAC by increased levels of sulfur-containing amino acids and GSH and equalized taurine and GSH levels in the control group. The Gln supplements also equalized the levels of GSH, Gln, and glycine in the control group. ConclusionAn increase in GSH may be attained by NAC or Gln supplementation, with NAC acting by increasing cysteine levels and Gln likely acting by replenishing the glycine pool (trial registered at http://www.clinicaltrials.gov, identifier NCT00910442).