Acetylcysteine ; urine ; Humans ; Hydrocarbons, Brominated ; metabolism ; urine

OBJECTIVETo explore the adduct characteristics of styrene and DNA.

METHODSThe adduct reactions between styrene, urinary mandalic acid(MA), phenylglyoxalic acid(PGA), mercapturic acid of styrene (UMA) and DNA were studied by ultraviolet spectral analysis. The SO-DNA adducts by 32P-post labeled method, the chemical structures of SO-DNA adducts by GC-MS and NMR were also studied.

RESULTSSO combined with DNA at O6, N2 positions of dGMP to form six adducts, but styrene, urinary mandalic acid, phenylglyoxalic acid and mercapturic acid of styrene did not react with DNA to form adduct.

CONCLUSIONSStyrene formed adduct with DNA through its active center metabolite--SO after entering the body. SO combined with DNA at O6, N2 positions of dGMP to form adducts. If these DNA adducts are not repaired or are mis-repaired before cell duplication, the gene mutation and chemical damage would happen. No adduct reactions are seen among other metabolites of styrene.

Acetylcysteine ; metabolism ; DNA ; metabolism ; DNA Adducts ; metabolism ; DNA Repair ; Glyoxylates ; metabolism ; Humans ; Mandelic Acids ; metabolism ; Styrene ; metabolism

AIMTo investigate the alleviating effect of N-acetylcysteine (NAC) on lung injury induced by lipopolysaccharides (LPS) and its mechanism.

METHODSThe effects of NAC on changes of the pulmonary arterial reactivity and the ultrastructure of pulmonary arterial endothelium induced by LPS were observed with the isolated artery ring technique and scanning electron microscope (SEM). Malondialdehyde (MDA), nitric oxide (NO) contents and superoxide dismutase (SOD) activity of pulmonary artery tissues were detected.

RESULTSThe exposure of pulmonary artery to LPS (4 microg/ml, 7 h) led to reduction of endothelium-dependent relaxation response to acetylcholine (ACh), which was reversed by the concomitant exposure to NAC (0.5 mmol/L, 7 h), whereas NAC itself had no effect on the response. Significant structural injury were observed under SEM in LPS group and alleviated the changes in LPS + NAC group. The MDA, NO contents increased but SOD activity decreased in LPS group, which were reversed by the concomitant exposure to NAC.

CONCLUSIONNAC protects pulmonary artery endothelium and enhances endothelium-dependent relaxation response of pulmonary artery by antioxidation effect, which may be one of the mechanisms of its reversing pulmonary artery hypertension and following lung injury induced by LPS.

Acetylcysteine ; pharmacology ; Animals ; Endothelium ; metabolism ; pathology ; ultrastructure ; Lipopolysaccharides ; adverse effects ; Malondialdehyde ; metabolism ; Microscopy, Electron, Scanning ; Nitric Oxide ; metabolism ; Pulmonary Artery ; metabolism ; pathology ; ultrastructure ; Rabbits ; Superoxide Dismutase ; metabolism

Oxidative stress and methylglyoxal (MG), a reactive dicarbonyl metabolites produced by enzymatic and non-enzymatic reaction of normal metabolism, induced aldose reductase (AR) expression in rat aortic smooth muscle cells (SMC). AR expression was induced in a time-dependent manner and reached at a maximum of 4.5-fold in 12 h of MG treatment. This effect of MG was completely abolished by cyclohemide and actinomycin D treatment suggesting AR was synthesized by de novo pathway. Pretreatment of the SMC with N-acetyl-L-cysteine significantly down-regulated the MG-induced AR mRNA. Furthermore, DL-Buthionine-(S,R)-sulfoximine, a reagent which depletes intracellular glutathione levels, increased the levels of MG-induced AR mRNA. These results indicated that MG induces AR mRNA by increasing the intracellular peroxide levels. Aminoguanidine, a scanvenger of dicarbonyl, significantly down-regulated the MG-induced AR mRNA. In addition, the inhibition of AR activities with statil, an AR inhibitor, enhanced the cytotoxic effect of MG on SMC under normal glucose, suggesting a protective role of AR against MG-induced cell damages. These results imply that the induction of AR by MG may contribute to an important cellular detoxification of reactive aldehyde compounds generated under oxidative stress in extrahepatic tissues.
Acetylcysteine ; Aldehyde Reductase* ; Animals ; Dactinomycin ; Glucose ; Glutathione ; Metabolism ; Muscle, Smooth, Vascular* ; Myocytes, Smooth Muscle ; Oxidative Stress* ; Pyruvaldehyde ; Rats ; RNA, Messenger

OBJECTIVETo observe the clinical efficacy of tetrandrine combined with acetylcysteine effervescent tablets in the treatment of silicosis.

METHODSA total of 96 patients with silicosis were randomly divided into treatment group (49 cases) and control group (47 cases). Both groups were given routine therapy including anti-inflammatory, antitussive, and antiasthmatic drugs, and the patients in treatment group were given tetrandrine combined with acetylcysteine effervescent tablets at the same time. Tetrandrine (100 mg) was orally administrated twice a day, and there was a one-day interval between every 6 days' continuous administration; totally, there were four courses of treatment, with 3 months for each course, and there was a one-month break between each course. Acetylcysteine effervescent tablets (600 mg) were taken twice a day; each course of treatment was 12 days, and there were four courses; for the first two months, there was one course per month, and then one course every other two months for the rest of time. Clinical symptoms, pulmonary ventilation function, serum superoxide dismutase (SOD) and changes in X-ray findings were observed.

RESULTSAfter treatment, the treatment group had significantly increased rates of improvements in cough, expectoration, chest congestion and pain, and dyspnea compared with the control group (P < 0.05). Compared with the control group (serum SOD level: 70.466±20.261 U/ml) and the treatment group before therapy (serum SOD level: 68.182±21.414 U/ml), the treatment group after therapy had significantly increased serum SOD level (77.389±21.315 U/ml?, forced vital capacity, and forced expiratory volume in one second (P < 0.05). Eight patients in treatment group showed improvement in the chest X-ray findings of silicosis.

CONCLUSIONThe combination of tetrandrine and acetylcysteine effervescent tablets show some effect in the treatment of silicosis. It can be an effective option for treating silicosis as there are no other specific remedies.

Acetylcysteine ; therapeutic use ; Aged ; Benzylisoquinolines ; therapeutic use ; Humans ; Male ; Middle Aged ; Silicosis ; drug therapy ; Superoxide Dismutase ; metabolism ; Treatment Outcome

OBJECTIVETo investigate the effects of Toll/interleukin 1 receptor domain-containing protein(TcpC)on macrophages and its mechanisms.

METHODSMurine macrophage J774A cells were co-cultured with TcpC producing wild type E. coli strain CFT073 (TcpC(wt)) or tcpc gene-deleted CFT073 mutant (TcpC(mut)) in Transwell system, respectively. Apoptosis of J774A cells co-cultured with TcpC(wt) or TcpC(mut) was analyzed by Annexin/PI double staining. The levels of reactive oxygen species (ROS) in J774A cells were determined by DCFH-DA staining after treatment with TcpC(wt) or TcpC(mut) at 6 h, 12 h,24 h or 36 h. After the ROS was scavenged by N-acetylcysteine (NAC), the changes of J774A cell apoptosis were also examined. The expression of caspase-3 in J774A cells co-cultured with TcpC(wt) or TcpC(mut) in the presence or absence of 0.1 mmol NAC was detected by Western blot.

RESULTSJ774A cells co-cultured with TcpC(wt) for 24 h or 36 h showed significantly increased apoptosis (27.39% ± 4.05% and 28.45% ± 4.55%,respectively) when compared to control group (7.96% ± 1.63% and 10.55% ± 1.44%,P<0.01) or TcpC(mut) group (11.45% ± 2.77% and 19.26%± 2.89%,P<0.01). Levels of ROS in J774A cells treated with TcpC(wt) for 24 h (108.8 ± 9.73) or 36 h (100.3 ± 10.11) were significantly higher than those in control group (56.8 ± 4.11 and 52.8 ± 4.42,P<0.01) or TcpC(mut) (69.7 ± 5.66 and 62.6 ± 4.56, P < 0.01). The pro-apoptotic effects of TcpC(wt) on J774A cells were reversed by 0.1 or 1 mMol NAC treatment. Expression of caspase-3 in J774A cells co-cultured with TcpC(wt) (0.43 ± 0.04) decreased significantly when compared to control group (0.75 ± 0.08,P<0.05) or TcpC(mut) group (0.80 ± 0.12,P<0.05). However,total caspase-3 expression was restored in J774A cells co-cultured with TcpC(wt) in the presence of 0.1 mmol NAC (0.80 ± 0.09).

CONCLUSIONTcpC can promote ROS production in macrophages,hereby inducing macrophage apoptosis.

Acetylcysteine ; pharmacology ; Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Escherichia coli ; metabolism ; Escherichia coli Proteins ; pharmacology ; Macrophages ; drug effects ; metabolism ; Mice ; Reactive Oxygen Species ; metabolism ; Virulence Factors ; pharmacology

OBJECTIVEN-Acetylcysteine (NAC) is a sulfhydryl donor molecule with antioxidant and antiinflammatory effects. A major role has been described for inducible nitric oxide (NO) synthase in several inflammatory liver diseases. NAC attenuates NO generation following lipopolysaccharide injection in rats. The purpose of this study was to investigate the effect of NAC against lipopolysaccharide injury in hepatocytes of neonatal mice and the molecular mechanisms by which NAC influences inflammatory responses of the hepatocytes.

METHODSThe liver of neonatal mouse was digested by collagenase to dissociate the hepatocytes. The hepatocytes were cultured and isolated. After 7 days of culture the normal hepatocytes were divided into two groups: LPS group and NAC group. In LPS group, 10 microg/ml LPS was added into the culture medium. In NAC group, 5 mmol/L NAC was added into the culture medium firstly, 10 microg/ml LPS was added after 1 h of culture. There were 12 mice in each group. The cell supernatants and the hepatocytes were collected at 0, 6 and 12 hours after adding LPS. The cell supernatants were taken to measure the alanine aminotransferase (ALT) level and nitric oxide (NO) production by the biochemical methods. The cells were taken to analyze the gene expression of induced nitric oxide synthase (iNOS) by the RT-PCR.

RESULTSIn LPS group, the levels of ALT, NO and iNOS mRNA increased significantly at the time points 6 h and 12 h compared with the time point 0, (P < 0.01). Compared with the LPS group, the levels of ALT, NO and iNOS mRNA of NAC group were lower at the time points 6 h and 12 h (P < 0.01).

CONCLUSIONSNAC may play a protective role in the hepatocytes injury caused by LPS in the neonatal mice. The protective mechanism works partially through the inhibition of iNOS activation by LPS.

Acetylcysteine ; pharmacology ; Alanine Transaminase ; metabolism ; Animals ; Animals, Newborn ; Anti-Inflammatory Agents ; pharmacology ; Cells, Cultured ; Hepatocytes ; drug effects ; Lipopolysaccharides ; Mice ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; metabolism

To explore the underlying mechanism(s) of pulmonary arterial hypertension in endotoxic shock, the roles of N-acetylcysteine (NAC), nitric oxide (NO) and carbon monoxide (CO) were investigated. Pulmonary arterial rings (3-mm width) were prepared from 24 rabbits. Lipopolysaccharide (LPS), after 7-hour incubation, decreased the endothelium-dependent relaxation response of the arterial ring (pre-contracted with phenylephrine) to acetylcholine (1 mumol/L), but did not affect the endothelium-independent relaxation response to sodium nitroprusside. The LPS effects were reduced by a concomitant incubation with the free radical scavenger (NAC), NO donor (L-arginine), and CO donor (hemin), respectively. On the other hand, the LPS effects were enhanced by applying heme oxygenase-1 (HO-1) inhibitor (zinc protoporphyrin) to block CO production. The response to acetylcholine changed from relaxation to contraction, however, the contractile response to phenylephrine increased significantly after pre-incubation with nitric oxide synthase (NOS) inhibitor (L-NAME) to block NO production, confirming the importance of CO and NO. These results show that LPS impairs endothelium-dependent relaxation of the pulmonary artery, which can be greatly reduced by the antioxidant, or by supplying with NO and CO. Thus, multiple factors are involved in this model of endotoxin-induced pulmonary hypertension.
Acetylcysteine ; metabolism ; Animals ; Carbon Monoxide ; metabolism ; Hypertension, Pulmonary ; etiology ; physiopathology ; Lipopolysaccharides ; toxicity ; Male ; Nitric Oxide ; metabolism ; Pulmonary Artery ; drug effects ; physiopathology ; Rabbits ; Shock, Septic ; complications

OBJECTIVETo investigate the effects of extremely low frequency electromagnetic field (ELF-EMF) on human osteosarcoma cells and its mechanisms.

METHODSHuman osteosarcoma MG-63 cells were exposed to 50 Hz,1 mT ELF-EMF for 1, 2 and 3 h in vitro, with or without pretreatment by reactive oxygen species (ROS) inhibitor N acetylcysteine (NAC) or p38MAPK inhibitor SB203580. The proliferation of MG-63 cells was determined by MTT method; the apoptosis rate and ROS level in MG-63 cells were detected by flow cytometry. The expression of p38MAPK in MG-63 cells was determined by Western blotting.

RESULTSELF-EMF decreased the viability of MG-63 cells, inhibited cell growth, induced cell apoptosis and increased the level of ROS significantly. The apoptosis rate declined significantly after treatment with ROS inhibitor NAC or p38MAPK inhibitor SB203580. After exposure to ELF-EMF, p38MAPK in MG-63 cells was activated, and the phosphorylation level was also inhibited after treatment with NAC.

CONCLUSIONELF-EMF can induce the apoptosis of MG-63 cells. Increased ROS and p38MAPK activation may be involved in the mechanism.

Acetylcysteine ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Electromagnetic Fields ; Humans ; Imidazoles ; Osteosarcoma ; pathology ; Oxidative Stress ; Phosphorylation ; Pyridines ; Reactive Oxygen Species ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

PURPOSE: Hyperglycemia increases reactive oxygen species (ROS) and the resulting oxidative stress plays a key role in the pathogenesis of diabetic complications. Nicotinamide dinucleotide phosphate (NADPH) oxidase is one of the major sources of ROS production in diabetes. We, therefore, examined the possibility that NADPH oxidase activation is increased in various tissues, and that the antioxidant N-acetylcysteine (NAC) may have tissue specific effects on NADPH oxidase and tissue antioxidant status in diabetes. MATERIALS AND METHODS: Control (C) and streptozotocin-induced diabetic (D) rats were treated either with NAC (1.5 g/kg/day) orally or placebo for 4 weeks. The plasma, heart, lung, liver, kidney were harvested immediately and stored for biochemical or immunoblot analysis. RESULTS: levels of free 15-F2t-isoprostane were increased in plasma, heart, lung, liver and kidney tissues in diabetic rats, accompanied with significantly increased membrane translocation of the NADPH oxidase subunit p67phox in all tissues and increased expression of the membrane-bound subunit p22phox in heart, lung and kidney. The tissue antioxidant activity in lung, liver and kidney was decreased in diabetic rats, while it was increased in heart tissue. NAC reduced the expression of p22phox and p67phox, suppressed p67phox membrane translocation, and reduced free 15-F(2t)-isoprostane levels in all tissues. NAC increased antioxidant activity in liver and lung, but did not significantly affect antioxidant activity in heart and kidney. CONCLUSION: The current study shows that NAC inhibits NADPH oxidase activation in diabetes and attenuates tissue oxidative damage in all organs, even though its effects on antioxidant activity are tissue specific.
Acetylcysteine/*therapeutic use ; Animals ; Antioxidants/*metabolism ; Diabetes Mellitus, Experimental/*drug therapy/*metabolism ; Heart/drug effects ; Kidney/drug effects/metabolism ; Liver/drug effects/metabolism ; Lung/drug effects/metabolism ; Male ; NADPH Oxidase/*metabolism ; Rats ; Rats, Sprague-Dawley