| The fumes from cooking foods and the burning of biomass and fossil fuels in stoves are the main source of cooking fumes.When using simple and poorly performing stoves to cook with biomass and fossil fuels,which are not fully combusted will emit particles fumes,and the surface of the smoke particles will adhere to metals,volatile organic compounds,polycyclic aromatic hydrocarbons(PAHs),benzene,hydrazine and carbonyl compounds.At present,there are few studies on the toxic effects and mechanisms related to the combustion of biomass and fossil fuel smoke from cooking.Therefore,this study aims to simulate the combined effect of representative components of biomass and fossil fuel combustion smoke in cooking source pollution.This has important theoretical significance and application value for revealing the toxic characteristics of dietary source smoke pollutants,comparing the toxicity differences of different particulates and conducting health hazard assessment of biomass and fossil fuel combustion smoke during cooking.In this study,CB(carbon black)N339 and a representative of polycyclic aromatic hydrocarbons(B[a]P,Benzo[a]pyrene)were selected as simulation materials for biomass and fossil fuel combustion smoke from cooking.We investigated the characterization of the CB-B[a]P particles and its toxic effects and mechanisms on NR8383 alveolar macrophages,as follows:(1)The CB-B[a]P particles was constructed with CB and B[a]P mass 1:1,and its hydrated particle size and potential were studied by dynamic light scattering DLS(Dynamic Light Scattering).The multi-point BET detection of the CB-B[a]P particles had a specific surface area of 27.197 m2/g,and its morphology was studied by means of scanning electron microscopy and transmission electron microscopy.(2)The effects of CB,B[a]P and CB-B[a]P particless on the activity of NR8383 alveolar macrophages were studied by MTT assay.CB(40 ?g/m L),B[a]P(40 ?g/m L)and CB-B[a]P particles(40 ?g/m L)were used as the subsequent experimental dose.The apoptosis rate was measured by Annexin V-FITC/PI,the mitochondrial membrane potential was detected by JC-1,the apoptotic cells were observed by DAPI staining,and the reactive oxygen species were detected by DCFH-DA probe.The study found that the CB-B[a]P particles(40 ?g/m L)group produced stronger toxic effects than the CB(40 ?g/m L)and B[a]P(40 ?g/m L)groups.The apoptotic rate and mitochondrial membrane potential were imbalanced.The CB-B[a]P particles group had the highest amount of ROS production,which is one of the causes of apoptosis of NR8383 cells caused by CB-B[a]P particles.(3)The cytotoxicity and mechanism of CB-B[a]P particles on NR8383 cells were further studied.The distribution of CB-B[a]P particles in cells was observed by transmission electron microscopy.It was found that CB-B[a]P particles can destroy the internal substructure of the cell,and observe the existence of a large number of autophagosome structures in the CB-B[a]P particles group.Western blot analysis of autophagy proteins such as LC3 and p62 revealed that the autophagy process of the CB-B[a]P particles group may be hindered.(4)To investigate the relationship between apoptosis and autophagy at the protein level,we treated NR8383 cells exposed to the CB-B[a]P particles group with chloroquine(CQ)and rapamycin(RAPA).Western blot results showed that CQ had no significant changes in apoptosis,while RAPA up-regulated the expression of LC3 and attenuated apoptosis caused by CB-B[a]P particles.In summary,the exposure of CB-B[a]P particles impaired the internal substructure of NR8383 alveolar macrophages,accumulating autophagosomes,and the release of intracellular ROS further leaded to changes in mitochondrial permeability and released Cytc to cytoplasm,which eventually initiated apoptosis.Our results help to understand the toxic mechanisms of indoor air pollutant particles in households cooking with biomass and fossil fuels,and provide a new understanding and experimental basis for their impacts on human health. |
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