RESUMO
Radon gas inhalation is the main source of exposure to ionizing radiation by humans. There is still lack in knowledge concerning the chronic and indirect effects of exposure to this carcinogenic factor. Therefore, the aim of this work is to analyze the levels of oxidative genomic damage in inhabitants of a medium-high background radiation area (HBRA) (N = 82) in Northeastern Brazil and compare them with people living in a low background radiation area (LBRA) (N = 46). 8-hydroxy-2-deoxyguanosine (8-OHdG) was quantified in urine, Ser326Cys polymorphism was determined in the hOGG1 gene and indoor radon was measured. HBRA houses had 6.5 times higher indoor radon levels than those from LBRA (p-value < 0.001). The 8-OHdG mean (95% confidence interval) were significantly different, 8.42 (5.98-11.9) ng/mg creatinine and 29.91 (23.37-38.30) ng/mg creatinine for LBRA and HBRA, respectively. The variables representing lifestyle and environmental and occupational exposures did not have a significant association with oxidized guanosine concentrations. On the other hand, lower 8-OHdG values were observed in subjects that had one mutant allele (326Cys) in the hOGG1 gene than those who had both wild alleles (Ser/Ser (p-value < 0.05). It can be concluded that high radon levels have significantly influenced the genome oxidative metabolism and hOGG1 gene polymorphism would mediate the observed biological response.
Assuntos
Radônio , Humanos , Radônio/toxicidade , Brasil , Creatinina , Desoxiguanosina , 8-Hidroxi-2'-Desoxiguanosina , Estresse Oxidativo , GenômicaRESUMO
Natural radioactivity is a public health concern worldwide. Its deleterious effects are largely associated with emitting ionizing particles which generate innumerable toxicological consequences to human being. The present study aimed to describe the research state of the art on natural radioactivity in Brazil through a systematic review limited to articles published in the twenty-first century in the PubMed, SciELO, Lilacs, and Google Scholar databases. A total of 55 research articles were considered for this purpose. Based on the collected sample types, the radiation analysis in most of the scientific reports was performed on solid samples (soil/sediment/rocks), followed by water and air. In fact, most of the available information came from geological studies. A wide range of concentrations and a variety of radionuclides have been assessed, with radium being the most cited. Most of the studies described radiation levels above the international guidelines, and consider the Brazilian territory as a high natural background radiation region (HNBR). In comparison with other HNBR areas, the scientific information about the related risks to human health is still scarce. There is uncertainty about the real impact of natural radioactivity on human health, as there is a lack of scientific information for most of the country about this issue. The analysis and comparison of the available information highlights the potential risks linked to natural radioactivity and the need to incorporate suitable environmental management policies about this issue.
Assuntos
Radiação de Fundo , Monitoramento de Radiação , Poluentes Radioativos do Solo/análise , Brasil , Geologia , Humanos , Radioatividade , Radioisótopos/análise , Rádio (Elemento)/análise , SoloRESUMO
Yam roots and other plants from Dioscorea genus have cultural, nutritional and economic importance to tropical and subtropical regions and have a great amount of diosgenin in its composition. In the present study the cytotoxic, genotoxic and mutagenic potential of diosgenin on HepG2 cells was investigated. Cytotoxicity was assessed using MTT and clonogenic assay. Genotoxic and mutagenic effects were performed using single cell gel electrophoresis and cytokinesis-block micronucleus assay, respectively. A reduction on cell viability was observed due to diosgenin treatment at concentrations higher than 30⯵M. A genotoxic effect was shown by comet assay and CBMN. Besides, an increase in micronucleus frequency along with a significant cytostatic effect were observed. Diosgenin elicited DNA damage on HepG2 cells which could not be efficiently repaired contributing to the mutagenic effect observed. Those results suggest that diosgenin deleterious effect could take place through genetic instability, fact that affects the normal cell cycle, leading to cell's death.