Juliana Moysés Reyes

Genetic and oxidative damage of peripheral blood lymphocytes in workers with occupational exposure to coal

Coal is an important fossil fuel used to generate energy. Coal dust is constituted primarily of hydrocarbons and metals. During coal extraction, large quantities of coal dust particles are emitted, contributing to environmental pollution. Coal miners are constantly exposed to coal dust and its derivatives. The goal of this study was to evaluate the potential genotoxic effects of coal and oxidative stress in individuals from Candiota who were exposed to coal as part of their occupation. The comet assay and micronucleus (MN) test were used to assess these effects. This study involved 128 male participants of whom 71 reported work that included exposure to coal (exposed group) and 57 reported working at different jobs (unexposed group). The exposed group had a significantly increased damage index and damage frequency, as assessed using the comet assay, and increased MN and nucleoplasmic bridge frequencies, as assessed using the MN assay, compared with unexposed individuals. Significant and positive correlations between MN frequencies in the lymphocytes and buccal cells of control and exposed individuals were observed. The exposed individuals presented lower average levels of thiobarbituric acid reactive substances (TBARS) and catalase activity (CAT), while the mean superoxide dismutase activity (SOD) levels were higher in this group. The exposed group also had higher hematocrit levels. No correlation between DNA damage and inorganic elements, as identified using PIXE, was found; however, there was a correlation between the damage index and zinc. The evidence that exposure to coal and its derivatives presents a genetic hazard demonstrates the need for protective measures and educational programs for coal miners.

Effects of quercetin on polychlorinated biphenyls-induced liver injury in rats

INTRODUCTION Polychlorinated biphenyls (PCBs), used as pesticides in agriculture, can lead to irreversible injuries in living organisms, particularly in liver. Oxidative stress has been implicated in the liver pathogenesis induced by different molecules, including PCBs. It has been demonstrated that quercetin, an antioxidant flavonoid found in the diet, exhibits a potent antioxidant effect in different liver pathologies. OBJECTIVE To evaluate oxidative stress caused by PCBs in liver and the antioxidant activity of quercetin. METHODOLOGY We used male Wistar rats (n = 36), divided in 4 groups: control, quercetin (50 mg/kg/day), PCBs (0.4 ml/kg/day), and rats treated with both PCBs and quercetin. On day 25 blood was collected to assess liver integrity (enzymes AST, ALT and ALP), and liver samples to measure oxidative stress (TBARS), activity of antioxidant enzymes (SOD, CAT, GPx) and DNA damage (micronucleus assay), and histological damage. RESULTS TBARS concentration and SOD activity were significantly higher in PCBs animals as compared to the PCB group receiving quercetin. CAT and GPx decreased in PCBs and increased when quercetin was added. The histological analysis showed damage to hepatocytes in PCBs, but quercetin was able to afford protection against such damage. The micronucleus test showed there was an increase in the production of microclenucleus compared to control, and quercetin was able to reduce this effect. CONCLUSION Contamination with PCBs led to increased lipid peroxidation and DNA damage, and the use of antioxidant quercetin was effective in reducing PCBs-induced liver injury.

Mitigation by vitamin C of the genotoxic effects of nicotine in mice, assessed by the comet assay and micronucleus induction.

Nicotine has been reported to cause acute toxicity and to present long-term risks, such as chromosomal damage and genetic instability. The genotoxicity of nicotine may be mediated partly by an oxidative mechanism. We have evaluated the effects of the antioxidant vitamin C on nicotine-induced genotoxicity in mice. The comet assay and the micronucleus test were used to assess the effects of nicotine (15mg/kg) at different exposure times (2, 4, and 24h in the comet assay; 24h in the micronucleus test). Pretreatment with vitamin C 24h before nicotine exposure strongly protected mice against nicotine-induced DNA damage.

Chemical and toxicological effects of medicinal Baccharis trimera extract from coal burning area

The entire process of power generation, extraction, processing and use of coal strongly impact water resources, soil, air quality and biota leads to changes in the fauna and flora. Pollutants generated by coal burning have been contaminating plants that grow in area impacted by airborne pollution with high metal contents. Baccharis trimera is popularly consumed as tea, and is widely developed in Candiota (Brazil), one of the most important coal burning regions of the Brazil. This study aims to investigate the phytochemical profile, in vivo genotoxic and mutagenic potential of extracts of B. trimera collected from an exposed region to pollutants generated by coal burning (Candiota City) and other unexposed region (Bagé City), using the Comet assay and micronucleus test in mice and the Salmonella/microsome short-term assay. The HPLC analyses indicated higher levels of flavonoids and phenolic acids for B. trimera aqueous extract from Bagé and absence of polycyclic aromatic hydrocarbons for both extracts. The presence of toxic elements such as cobalt, nickel and manganese was statistically superior in the extract from Candiota. For the Comet assay and micronucleus test, the mice were treated with Candiota and Bagé B. trimera aqueous extracts (500-2000 mg/kg). Significant genotoxicity was observed at higher doses treated with B. trimera aqueous extract from Candiota in liver and peripheral blood cells. Micronuclei were not observed but the results of the Salmonella/microsome short-term assay showed a significant increase in TA98 revertants for B. trimera aqueous extract from Candiota. The extract of B. trimera from Candiota bioacumulated higher levels of trace elements which were associated with the genotoxic effects detected in liver and peripheral blood cells.

USE OF BUCCAL MICRONUCLEUS ASSAY TO DETERMINE MUTAGENICITY INDUCED BY AMFEPRAMONE IN HUMANS AND THE PROTECTIVE EFFECTS OF VITAMIN C

The abusive use of amfepramone in Brazilian population has grown in recent years. Few studies have been conducted on amphetamine with respect to DNA damage, and there have been no apparent investigations examining the influence of amfepramone on humans. The aim of this study was to determine the possible mutagenic actions of amfepramone on humans using the micronucleus (MN) assay with buccal cells and the effects of supplementation with vitamin C as a potential protective agent. The study included 108 females with 52 as control and 56 taking amfepramone at 120 mg/d for at least the whole previous month. All women were intentionally selected to be nonsmokers and nondrinkers. After 30 d of amfepramone women were given amfepramone plus vitamin C use at 1000 mg/d for another month. Results showed a marked increase in the number of MN in amfepramone users in both basal and differentiated cells, indicating a mutagenic action. After vitamin C supplementation, a significant decrease in the frequency of MN and apoptosis was observed. Evidence indicates that the main mechanism of action of amfepramone in inducing DNA damage occurs through formation of reactive oxygen species (ROS), intercalation and topoisomerase binding, attributed to the presence of an N-dialkyl group. In addition, data demonstrated that vitamin C effectively inhibited amfepramone-induced DNA damage.The abusive use of amfepramone in Brazilian population has grown in recent years. Few studies have been conducted on amphetamine with respect to DNA damage, and there have been no apparent investigations examining the influence of amfepramone on humans. The aim of this study was to determine the possible mutagenic actions of amfepramone on humans using the micronucleus (MN) assay with buccal cells and the effects of supplementation with vitamin C as a potential protective agent. The study included 108 females with 52 as control and 56 taking amfepramone at 120 mg/d for at least the whole previous month. All women were intentionally selected to be nonsmokers and nondrinkers. After 30 d of amfepramone women were given amfepramone plus vitamin C use at 1000 mg/d for another month. Results showed a marked increase in the number of MN in amfepramone users in both basal and differentiated cells, indicating a mutagenic action. After vitamin C supplementation, a significant decrease in the frequency of MN and apoptosis was observed. Evidence indicates that the main mechanism of action of amfepramone in inducing DNA damage occurs through formation of reactive oxygen species (ROS), intercalation and topoisomerase binding, attributed to the presence of an N-dialkyl group. In addition, data demonstrated that vitamin C effectively inhibited amfepramone-induced DNA damage.