RESUMO
Epidemiological studies have shown that air particulate matter (PM) can increase respiratory morbidity and mortality being the lungs the main target organ to PM body entrance. Even more, several in vivo and in vitro studies have shown that air PM has a wide toxicity spectra depending among other parameters, on its size, morphology, and chemical composition. The Reconquista River is the second most polluted river from Buenos Aires, and people living around its basin are constantly exposed to its contaminated water, soil and air. However, the air PM from the Reconquista River (RR-PMa) has not been characterized, and its biological impact on lung has yet not been assessed. Therefore, the present investigation was undertaken to study (1) RR-PMa morphochemical characteristic and (2) RR-PMa lung acute effects after intranasal instillation exposure through the analysis of three end points: oxidative stress, inflammation, and apoptosis. A single acute exposure of RR-PMa (1 mg/kg body weight) after 24 h caused significant (p < 0.05) enrichment in bronchoalveolar total cell number and polymorphonuclear (PNM) fraction, superoxide anion generation, production of pro-inflammatory cytokines TNF-α and IL-6, and induction of apoptosis. It was also observed that in lung homogenates, none of the antioxidant enzymes assayed showed differences between exposed RR-PMa and control mice. These data demonstrate that air PM from the Reconquista River induce lung oxidative stress, inflammation, and cell death therefore represents a potential hazard to human health.
Assuntos
Poluentes Atmosféricos/toxicidade , Material Particulado/toxicidade , Pneumonia/induzido quimicamente , Animais , Argentina , Morte Celular , Monitoramento Ambiental , Masculino , CamundongosRESUMO
Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5-200 µM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO3 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO3. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O2â»). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O2â» may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O2â» may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium-related diseases.
Assuntos
Mediadores da Inflamação/fisiologia , Macrófagos Alveolares/efeitos dos fármacos , Superóxidos/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Nitrato de Uranil/toxicidade , Animais , Apoptose , Compostos Azo , Caspase 3/metabolismo , Morte Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/ultraestrutura , Células Cultivadas , Corantes , Imuno-Histoquímica , Macrófagos Alveolares/metabolismo , Masculino , Fagocitose/efeitos dos fármacos , Poli(ADP-Ribose) Polimerases/metabolismo , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Sais de Tetrazólio , TiazóisRESUMO
Air particulate matter has been associated with adverse effects in the cardiorespiratory system leading to cytotoxic and pro-inflammatory effects. Particulate matter-associated cardiac effects may be direct or indirect. While direct interactions may occur when inhaled ultrafine particles and/or particle components cross the air-blood barrier reaching the cardiac tissue, indirect interactions may occur as the result of pulmonary inflammation and consequently the release of inflammatory and oxidative mediators into the blood circulation. The aim of the study is to investigate the direct or indirectly the effect of Urban Air particles from downtown Buenos Aires (UAP-BA) and residual oil fly ash (ROFA), a surrogate of ambient air pollution, on cardiomyocytes (HL-1 cells). HL-1 cultured cells were directly exposed to particulate matter [UAP-BA (10-200 µg/ml), ROFA (1-100 µg/ml)] or indirectly exposed to conditioned media (CM) from particle-exposed alveolar macrophages (AM). Metabolic activity, reactive oxygen species (ROS), and Nrf2 expression were assessed by MTT, DHR 123, and immunocytochemistry techniques, respectively. We found that direct exposure of cardiomyocytes to UAP-BA or ROFA increased ROS generation but the oxidative damage did not alter metabolic activity likely by a concomitant increase in the cytoplasmic and nuclear Nrf2 expression. However, indirect exposure through CM caused a marked reduction on cardiac metabolic activity probably due to the rise in ROS generation without Nrf2 translocation into the cell nuclei. In this in vitro model, our results indicate both direct and indirect PM effects on cardiomyocytes cells in culture. Our findings employing lung and cardiomyocytes cells provide support to the hypothesis that particle-induced cardiac alteration may possibly involve lung-derived mediators.
Assuntos
Poluentes Atmosféricos/toxicidade , Miócitos Cardíacos/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Material Particulado/toxicidade , Animais , Argentina , Linhagem Celular , Meios de Cultivo Condicionados/metabolismo , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Estresse Oxidativo/efeitos dos fármacos , Comunicação Parácrina/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de SinaisRESUMO
Air particulate matter has been associated with adverse impact on the respiratory system leading to cytotoxic and proinflammatory effects. The biological mechanisms behind these associations may be initiated by inhaled small size particles, particle components (soluble fraction) and/or mediators released by particle-exposed cells (conditioned media). The effect of Urban Air Particles from Buenos Aires (UAP-BA) and Residual Oil Fly Ash (ROFA) a surrogate of ambient air pollution, their Soluble Fractions (SF) and Conditioned Media (CM) on A549 lung epithelial cells was examined. After 24 h exposure to TP (10 and 100 µg/ml), SF or CM, several biological parameters were assayed on cultured A549 cells. We tested cell viability by MTT, superoxide anion (O2(-)) generation by NBT and proinflammatory cytokine (TNFα, IL-6 and IL-8) production by ELISA. UAP-BA particles or its SF (direct effect) did not modify cell viability and generation of O2(-) for any of the doses tested. On the contrary, UAP-BA CM (indirect effect) reduced cell viability and increased both generation of O2(-) and IL-8 production. Exposure to ROFA particles, SF or ROFA CM reduced proliferation and O2(-) but, stimulated IL-8. It is worth to note that UAP-BA and ROFA depicted distinct effects on particle-exposed A549 cells implicating morphochemical dependence. These in vitro findings support the hypothesis that particle-induced lung inflammation and disease may involve lung-derived mediators.
Assuntos
Poluentes Atmosféricos/toxicidade , Células Epiteliais/efeitos dos fármacos , Material Particulado/toxicidade , Alvéolos Pulmonares/citologia , Argentina , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cidades , Meios de Cultivo Condicionados/toxicidade , Citocinas/metabolismo , Células Epiteliais/metabolismo , Humanos , Superóxidos/metabolismoRESUMO
Exposure to uranium is an occupational hazard to workers who continually handle uranium and an environmental risk to the population at large. Since the cellular and molecular pathways of uranium toxicity in osteoblast cells are still unknown, the aim of the present work was to evaluate the adverse effects of uranyl nitrate (UN) on osteoblasts both in vivo and in vitro. Herein we studied the osteoblastic ultrastructural changes induced by UN in vivo and analyzed cell proliferation, generation of reactive oxygen species (ROS), apoptosis, and alkaline phosphatase (APh) activity in osteoblasts exposed to various UN concentrations (0.1, 1, 10, and 100 microM) in vitro. Cell proliferation was quantified by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, ROS was determined using the nitro blue tetrazolium test, apoptosis was morphologically determined using Hoechst 3332 and APh activity was assayed spectrophotometrically. Electron microscopy revealed that the ultrastructure of active and inactive osteoblasts exposed to uranium presented cytoplasmic and nuclear alterations. In vitro, 1-100 microM UN failed to modify cell proliferation ratio and to induce apoptosis. ROS generation increased in a dose-dependent manner in all tested doses. APh activity was found to decrease in 1-100 microM UN-treated cells vs. controls. Our results show that UN modifies osteoblast cell metabolism by increasing ROS generation and reducing APh activity, suggesting that ROS may play a more complex role in cell physiology than simply causing oxidative damage.