RESUMO
To study central nervous system airborne PM related subchronic toxicity, SD male rats were exposed for eight weeks to either coarse (32 µg/m³), fine (178 µg/m³) or ultrafine (107 µg/m³) concentrated PM or filtered air. Different brain regions (olfactory bulb, frontal cortex, striatum and hippocampus), were harvested from the rats following exposure to airborne PM. Subsequently, prooxidant (HO-1 and SOD-2), and inflammatory markers (IL-1ß and TNFα), apoptotic (caspase 3), and unfolded protein response (UPR) markers (XBP-1S and BiP), were also measured using real-time PCR. Activation of nuclear transcription factors Nrf-2 and NF-κB, associated with antioxidant and inflammation processes, respectively, were also analyzed by GSMA. Ultrafine PM increased HO-1 and SOD-2 mRNA levels in the striatum and hippocampus, in the presence of Nrf-2 activation. Also, ultrafine PM activated NF-κB and increased IL-1ß and TNFα in the striatum. Activation of UPR was observed after exposure to coarse PM through the increment of XBP-1S and BiP in the striatum, accompanied by an increase in antioxidant response markers HO-1 and SOD-2. Our results indicate that exposure to different size fractions of PM may induce physiological changes (in a neuroanatomical manner) in the central nervous system (CNS), specifically within the striatum, where inflammation, oxidative stress and UPR signals were effectively activated.
Assuntos
Poluentes Atmosféricos/toxicidade , Fármacos do Sistema Nervoso Central/toxicidade , Corpo Estriado/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Material Particulado/toxicidade , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Poluentes Atmosféricos/química , Animais , Biomarcadores/metabolismo , Fármacos do Sistema Nervoso Central/química , Corpo Estriado/imunologia , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Chaperona BiP do Retículo Endoplasmático , Proteínas de Choque Térmico/biossíntese , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Heme Oxigenase (Desciclizante)/biossíntese , Heme Oxigenase (Desciclizante)/genética , Heme Oxigenase (Desciclizante)/metabolismo , Masculino , México , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios/imunologia , Tamanho da Partícula , Material Particulado/química , Ratos , Ratos Sprague-Dawley , Fatores de Transcrição de Fator Regulador X , Superóxido Dismutase/biossíntese , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Regulação para Cima/efeitos dos fármacos , Proteína 1 de Ligação a X-BoxRESUMO
The implications of delta-aminolevulinic acid dehydratase (ALAD) polymorphism for lead kinetics and toxicity have been mainly studied in occupationally exposed adults. Therefore, our purpose was to evaluate the distribution of ALAD genotype and its association with biomarkers of exposure (PbB levels) and effect (Blood ZPP) among children living in a smelter community in Mexico. We recruited 569 children from nine elementary schools close to a smelter site. PbB was determined by electrothermal atomic absorption spectrometry. A polymerase chain reaction (PCR)-based protocol was used for ALAD genotyping. Zinc protoporphyrin (ZPP) in blood was measured by direct fluorometry. Most children (93.15%) were homozygous for ALAD (1-1), 6.67% were heterozygous for ALAD for (1-2), and one child was homozygous for ALAD (2-2). There was an increased proportion of ALAD (1-2/2-2) genotype with respect to PbB levels. The ZPP geometric mean was slightly higher in ALAD (1-1) genotype children (63.48 mu mol ZPP/mol Hb) than in those having the ALAD-2 genotype (58.22 mu mol ZPP/mol Hb; p = 0.051). Linear and quadratic models showed significant relationships between ZPP and PbB. A significant increase in the odds ratio (OR) for the effect of lead exposure on ZPP levels was observed for ALAD (1-1) children having PbB values above 20 mu g/dL, as compared to those having PbB levels below 10 mu g/dL (OR = 2.95, 95% CI = 1.45-5.97; p = 0.003), whereas no significant increases were observed for the ALAD (1-2/2-2) children. In summary, our results suggest that heme biosynthesis was less affected in ALAD (1-2/2-2) lead-exposed children than in those carrying the ALAD (1-1) genotype.
RESUMO
Irradiation of sewage sludge reduces pathogens and can hydrolyze or destroy organic molecules. The effect of irradiation of sewage sludge on C and N dynamics in arable soil and possible interference with toxic organic compounds was investigated in soil microcosms using a clay soil. The soil was treated with phenanthrene and anthracene, with and without irradiated and non-irradiated sewage sludge amendment. All the treated soils were incubated for 182 days at 25 degrees C. The CO2 production and dynamics of inorganic N (NH4+, NO2- and NO3-) were monitored. Addition of sewage sludge (0.023 g g(-1) soil), anthracene or phenanthrene (10.0 microg g(-1) soil dissolved in methanol), and methanol (10 mg g(-1) soil) to soil had a significant effect on CO2 production compared to the control. However, there were no significant differences between soil treated with irradiated and non-irradiated sewage sludge. Irradiated sewage sludge increased the C and N mineralization of anthracene amended soils to a greater extend than in phenanthrene amended soils. Nitrification was inhibited for 28 days in soil treated with either methanol, anthracene and phenanthrene. Application of sewage sludge reduced such toxicity effects after 28 days incubation.
Assuntos
Silicatos de Alumínio/efeitos da radiação , Antracenos/química , Dióxido de Carbono/metabolismo , Compostos de Nitrogênio/metabolismo , Fenantrenos/química , Esgotos/química , Microbiologia do Solo , Silicatos de Alumínio/química , Antracenos/metabolismo , Carbono/química , Carbono/metabolismo , Argila , Enterobacteriaceae/metabolismo , Enterobacteriaceae/efeitos da radiação , Metanol/metabolismo , Minerais/química , Minerais/metabolismo , Nitrogênio/química , Nitrogênio/metabolismo , Compostos de Nitrogênio/química , Fenantrenos/metabolismo , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Esgotos/microbiologia , Solo/análiseRESUMO
Industrial growth has created the potential for environmental problems in Mexico, since attention to environmental controls and urban planning has lagged behind the pace of industrialization. The aim of this cross-sectional study was to assess lead exposure in children aged 6-9 yr attending 3 primary schools and living in the vicinity of the largest smelter complex in Mexico. One of the schools is located 650 m distant from a smelter complex that includes a lead smelter (close school); the second is located 1750 m away from the complex and at the side of a heavy traffic road (intermediate school) in Torreon, Coahuila. The third school is located in Comez Palacio, Durango, 8100 m away from the smelter complex and distant from heavy vehicular traffic or industrial areas (remote school). Lead was measured in air, soil, dust, and well water. Lead in blood (PbB) was determined in 394 children attending the above mentioned schools. Determinations were performed by atomic absorption spectrometry. Diet, socioeconomic status, hygienic habits, and other variables were assessed by questionnaire. Median (range) PbB values were 7.8 microg/dl (3.54-29.61) in the remote school, 21.8 microg/dl (8.37-52.08) in the intermediate school and 27.6 microg/dl (7.37-58.53) in children attending the close school. The percentage of children with PbB > 15 microg/dl was 6.80%, 84.9%, and 92.1% respectively. In this order, the geometric means (range) of Pb concentrations in air were 2.5 microg/m3 (1.1-7.5), 5.8 microg/m3 (4.3-8.5), and 6.1 microg/m3 (1.6-14.9). The Pb concentrations in dust from playgrounds areas in the intermediate and close school settings ranged from 1,457 to 4,162.5 mg/kg. Pb concentrations in drinking water were less than 5 microg/L. Soil and dust ingestion and inhalation appear to be the main routes of exposure. Our results indicate that environmental contamination has resulted in an increased body burden of Pb, suggesting that children living in the vicinity of the smelter complex are at high risk for adverse effects of lead.