The effects of functionalization of carbon nanotubes on toxicological parameters in mice

Carbon nanotubes (CNTs) have emerged as a new class of multifunctional nanoparticles in biomedicine, but their multiple in vivo effects remain unclear. Also, the impact of various functionalization types and duration of exposures are still unidentified. Herein, we report a complete toxicological study to evaluate the effects of single- and multiwalled carbon nanotubes (SWCNTs and MWCNTs) with either amine or carboxylic acid (COOH) surface functional groups. The results showed that significant oxidative stress and the subsequent cell apoptosis could be resulted in both acute and, mainly, in chronic intravenous administrations. Also, male reproductive parameters were altered during these exposures. The amino-functionalized CNTs had more toxic properties compared with the COOH functionalized group, and also, in some groups, the multiwalled nanotubes were more active in eliciting cytotoxicity than the single-walled nanotubes. Interestingly, the SWCNTs-COOH had the least alterations in most of the parameters. Evidently, it is concluded that the toxicity of CNTs in specific organs can be minimized through particular surface functionalizations.

Metal(loid)s urinary level among workers of gas refinery and petrochemical companies: Health risk assessment of metal(loid)s in drinking water and dust

BACKGROUND

Asalouyeh (southern Iran) contains many pollution sources like petrochemical and gas refinery companies. Few studies were conducted on the body burden of metal(loid)s in occupationally exposed workers of the companies in this area.

OBJECTIVES

The urine concentration of metal(loid)s in workers of gas refinery and petrochemical companies in Asalouyeh (who have been worked as "two weeks work-two weeks rest" schedule) was evaluated during a before-and-after observational study. The risks of metal(loid)s in drinking water and dust particles in the studied area were also assessed.

METHODS

Urinary samples (n = 179) were gathered at the first day of two weeks of work (before) and at the end of two weeks of work (after). The concentration of V, Ni, Mn, Cd, and As was measured using a graphite furnace atomic absorption spectrometry. The health hazards of metal(loid)s in the air dust and drinking water of workers were also evaluated.

RESULTS

The median concentration of metal(loid)s for workers of gas refinery and petrochemical companies for before and after two weeks of work was measured, respectively, as: As (11.44 and 9.31 μg/L), Ni (1.06 and 0.51 μg/L), Cd (0.36 and 0.31 μg/L), Mn (0.29 and 0.24 μg/L), and V (0.08 and 0.05 μg/L). After two weeks work, the median of all metal(loid)s in the urine of petrochemical and gas refinery workers was significantly increased. The non-cancer risk due to intake metal(loid)s from drinking water was more than the threshold value and the cancer risk from drinking water and inhaled air dust was less than the threshold.

CONCLUSION

Our results revealed the effect of gas refinery and petrochemical activities on increasing the metal(loid)s concentration of the worker's body and the necessity to protect this group. Additionally, the metal(loid)s intake from drinking water and inhaled dust posed no cancer risk to the workers.

The effects of methanolic extract of Glycyrrhiza glabra on the prevention and treatment of bleomycin-induced pulmonary fibrosis in rat: experimental study

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by dyspnea and progressive loss of lung function. In this study, the preventive and therapeutic effects of methanolic extract of Glycyrrhiza glabra on pulmonary fibrosis were investigated. Pulmonary fibrosis was induced by administration of bleomycin (BLM) into the left lung of rats. Methyl-prednisolone (M-pred, 4 mg/kg) and methanolic extract of G. glabra (500 mg/kg) were injected intraperitoneally from the 1st to 14th days in the preventive group and from the 14th to 28th days in the therapeutic group once every day. Pulmonary inflammatory and fibrotic indices were evaluated by hematoxylin and eosin (H&E) and Masson's trichrome, respectively. The level of hydroxyproline as an index of pulmonary fibrosis and malondialdehyde (MDA) as an oxidative stress biomarker and catalase were measured by the related ELISA Kits. Pulmonary inflammatory and fibrotic indices in the G. glabra and M-pred groups significantly reduced compared with BLM group. G. glabra decreased the level of hydroxyproline in pulmonary tissue similar to M-pred. MDA reduced in G. glabra and M-pred groups compared with BLM group. The activity of catalase increased in the G. glabra preventive group. According to the results, G. glabra prevented and treated pulmonary fibrosis and inflammation in rats. Therefore, G. glabra may be suggested for the prevention and treatment of pulmonary fibrosis and inflammation.

Oxidative stress in opium users after using lead-adulterated opium: The role of genetic polymorphism

Use of lead-adulterated opium has become one of the major sources of lead poisoning in Iran. This study was designed to assess clinical effects and oxidative stress and its association with GSTM1, GSTT1, NQO1, and ALAD genes polymorphisms and blood lead level (BLL) in lead-adulterated opium users. The oxidative stress status in 192 opium users with lead poisoning symptoms measured and compared with 102 healthy individuals. Gluthatione S-transferase (GST)-M1 and -T1 genes deletion, NQO1 rs1800566, and δ-aminolevulinic acid dehydratase (ALAD) rs1800435 polymorphisms were determined using PCR and PCR-RFLP. The relation between the polymorphisms, BLL, and oxidative stress parameters were analysed using multivariate linear regressions. The common symptoms of lead toxicity were gastrointestinal and neurologic complications. Oxidative stress was significantly higher in opium addicts and lipid peroxidation significantly correlated with BLL. There was significant association between ALAD rs1800435 and BLL, and the BLL was significantly lower in the patients with ALAD 1-2 genotype. Use of lead-adulterated opium causes high frequency of lead toxicity symptoms, hematological and biochemical abnormalities, and oxidative stress which are associated with BLL. Route of opioid use and the polymorphism of rs1800435 in ALAD gene are the major determinants of BLL in lead-adulterated opium users.

Mancozeb induces testicular dysfunction through oxidative stress and apoptosis: Protective role of N-acetylcysteine antioxidant

Mancozeb (MZB) is one of the fungicides used in pest control programs that might affect human health including reproductive system. The aim of this study was to demonstrate the mechanisms through which MZB induces testicular tissue damage and the probable protective effect of N-acetylcysteine (NAC), a modified amino acid, with antioxidant property, against MZB toxicity in an animal model. Male albino mice ( n = 8) were exposed to different doses of MZB (250 and 500 mg/kg/day) by oral gavage without or with NAC (200 mg/kg, twice/week) for 40 days. Sub-chronic MZB dose-dependently decreased sperm motility and count. Exposure to MZB increased lipid peroxidation and protein carbonyl, while it reduced antioxidant enzymes activities, total antioxidant capacity, and glutathione content. The histopathological examination clearly showed deleterious changes in the testicular structure. At the molecular levels, the results of quantitative real time-poly chain reaction (qRT-PCR) showed that MZB upregulated oxidative stress markers inducible nitric oxide synthase (iNOS) and NADPH oxidase 4 (NOX4) and downregulated expression of the glutathione peroxidase 1 (Gpx1) gene as one of the most important antioxidant enzymes. MZB also induced apoptosis dose-dependently in the testes as determined by the terminal dUTP nick-end labeling assay and immunoblotting. NAC administration decreased the mRNA levels of both iNOS and NOX4 with a concomitant increase in Gpx1 expression. It also significantly decreased MZB-induced oxidative stress and apoptosis. Collectively, the present study showed MZB-induced oxidative damage in testes leading to apoptosis. It revealed that antioxidants such as NAC can mitigate oxidant injury induced by the dithiocarbamate pesticides in the reproductive system.

Hematological Abnormality, Oxidative Stress, and Genotoxicity Induction in the Greenhouse Pesticide Sprayers; Investigating the Role of NQO1 Gene Polymorphism

The widespread use of pesticides in agriculture represents a threat to the human populations exposed to them. In this cross-sectional study, the hematological and biochemical parameters, plasma cholinesterase (PChE) activity, oxidative stress, genotoxicity, and NAD(P)H: quinone oxidoreductase 1 (NQO1) C609T polymorphism were measured in 100 greenhouse workers occupationally exposed to pesticide mixture and 104 normal healthy controls. There was a decrease in erythrocytes (5.45%, p = 0.026) and hemoglobin (3.26%, p = 0.025), and an increase in mean corpuscular hemoglobin (3.54%, p = 0.013) in the exposed workers. Sprayers showed a reduction in PChE (23%) and GSH (50%) levels, and an increase in lipid peroxidation (LPO) (55%), protein carbonyl (145%), Superoxide dismutase activity (61%), and total antioxidant capacity (35%) (p < 0.001 for all parameters but LPO: p = 0.009). Genotoxicity parameters were significantly high in the exposed cases (for all parameters: p < 0.001 but tail length: p = 0.002). There was a significant correlation between oxidative stress and genotoxicity parameters, and also between these biomarkers and PChE activity. The NQO1 C609T polymorphism was not significantly associated with studied biomarkers. The findings indicate that occupational exposure to a mixture of pesticides can induce hematotoxicity, oxidative stress, and genotoxicity in greenhouse workers.

Pharmacological safety evaluation of a traditional herbal medicine "Zereshk-e-Saghir" and assessment of its hepatoprotective effects on carbon tetrachloride induced hepatic damage in rats

ETHNOPHARMACOLOGICAL RELEVANCE

"Zereshk-e-Saghir" (ZES), one of the traditional herbal medicines in old manuscripts of Persian hakims, has been used for the treatment of liver disorders. This current study is aimed to evaluate ZES effects on animal model to investigate its safety and hepatoprotective activity.

MATERIALS AND METHODS

ZES was prepared according to a traditional method by blending aqueous extracts of Berberis vulgaris L., with fine particles of other plants including Rosa damascene Mill, Cichorium intybus L., Cucumis sativus L., Portulaca oleracea L., Rheum palmatum L., and Nardostachys jatamansi DC.. The lethality of ZES was determined in male NMRI mice. Acute organ toxicity of ZES (750 and 1500mg/kg for 15 days, orally) was evaluated by measuring the cell blood count, liver marker enzymes, creatinine, antioxidant status and histopathological examinations in rats. CCl4-induced liver toxicity was used to examine the hepatoprotective effects of the preparation. The rats were pretreated with 250, 500, 750 and 1500mg/kg ZES by gavage for 15 days. At day 16, the rats were intraperitoneally injected 1ml/kg CCl4 in olive oil. Forty-eight hours after CCl4 injection, the animals were sacrificed and their liver samples and blood were collected for determination of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase (ALT, AST, and ALP), histopathological examinations and antioxidant status.

RESULTS

Treatment of the mice with a single dose of ZES up to 2g/kg did not cause mortality. Treatment of the rats with doses of 750 and 1500mg/kg for 15 days showed no significant hematotoxicity and hepatotoxicity. Treatment of the rats with ZES reduced the increased serum levels of ALT, AST, and ALP induced by CCl4 at the doses of 250, 500, and 750mg/kg. This was almost confirmed by histopathological examinations. Pretreatment with ZES also decreased lipid peroxidation and maintained the levels of glutathione and total antioxidant capacity.

CONCLUSIONS

The present in vivo study revealed that the long term usage of ZES was safe for organs in laboratory animals. Meanwhile, prescribing the traditionally-recommended dose of ZES can be probably used against the liver injuries induced by xenobiotics. Further studies in other models of liver injuries are recommended for finding the exact hepatoprotective mechanism of ZES.

Thymoquinone effectively alleviates lung fibrosis induced by paraquat herbicide through down-regulation of pro-fibrotic genes and inhibition of oxidative stress

The potential preventive and therapeutic effects of thymoquinone (TQ) and its molecular mechanism were evaluated in paraquat (PQ)-induced pulmonary fibrosis in mice. TQ was administered orally at the doses of 20 and 40mg/kg during the course and after development of fibrosis. Pathological changes, expressions of genes involved in fibrogenesis, hydroxyproline (HP) and oxidative stress parameters were determined in the lung tissues. TQ dose-dependently recovered the pathological changes induced by PQ. TQ decreased hydroxyproline content, lipid peroxidation and restored the antioxidant enzymes to the normal values. In molecular level, expressions of TGF-β1, α-SMA, collagen 1a1 and collagen 4a1 genes were also returned to the control level by TQ. This study indicated that TQ has the preventive and therapeutic potentials for the treatment of lung fibrosis by inhibition of oxidative stress and down-regulation of profibrotic genes.

Hepatoprotective effect of silyamarin in individuals chronically exposed to hydrogen sulfide; modulating influence of TNF-α cytokine genetic polymorphism

BACKGROUND AND THE PURPOSE OF THE STUDY

Silymarin, a standardized extract of the milk thistle (Silybum marianum), is believed to exert some of its hepatoprotective effects though inhibition of free radicals and inflammation. In this study the effect of some pro- and anti-inflammatory cytokines and also antioxidant genes polymorphisms on the hepatoprotective effects of silymarin in the occupationally exposed individuals to hydrogen sulfide (H2S) in the sour natural gas refinery was investigated.

METHODS

We genotyped seven polymorphisms in six genes reported by others as modifiers of oxidative stress (NQO1, mEPXH1, GSTT1 and GSTM1) and inflammation (TNF-α and TGF-β1) for an association in effect of decreasing in liver function tests (LFTs). The LFTs of 77 sour gas refinery workers were measured before and after administration of silymarin (140 mg, three times per day for 1 month).

RESULTS

A significant reduction of blood AST, ALT and ALP was observed after 30 days of consumption (p < 0.001). The decreasing effect of silymarin on ALT in the subjects with high producer genotype (A allele carriers) was less than low producers. There were no significant associations between TGF-β1 and the studied genes of oxidative stress pathway and the effectiveness of silymarin.

CONCLUSION

This is the first report about the effectiveness of silymarin in the subjects exposed chronically to H2S. Meanwhile, the modulatory effect of TNF-α on the effectiveness of silymarin might be used for individualize therapy.