A novel particulate matter sampling and cell exposure strategy based on agar membrane for cytotoxicity study.

Laboratories use different strategies to sample and extract atmospheric particulate matter (PM), some of which can be very complicated. Due to the absence of a standard protocol, it is difficult to compare the results of PM toxicity assessment across different laboratories. Here, we proposed a novel PM sampling and cell exposure strategy based on agar membrane. The agar membrane, prepared by a simple freeze-drying method, has a relatively flat surface and porous interior. We demonstrated that the agar membrane was a reliable substitute material for PM sampling. Then the PM on the agar membranes was directly extracted with the culture medium by vortex method, and the PM on the polytetrafluoroethylene (PTFE) filters was extracted with water by the traditional ultrasonic method for comparison. The extraction efficiency was evaluated and in vitro cytotoxicity assays were carried out to investigate the toxic effects of PM extracted with two strategies on macrophage cells. The results showed that the PM extracted from agar membranes induced higher cytotoxicity and more differentially expressed proteins. Overall, the novel PM sampling-cell exposure strategy based on the agar membrane is easy to operate, biocompatible and comparable, and has low disturbance, could be an alternative sampling and extraction method for PM toxicity assessment.

Cytotoxicity and toxicoproteomic analyses of human lung epithelial cells exposed to extracts of atmospheric particulate matters on PTFE filters using acetone and water.

Differences of cytotoxicity associated with exposure to different extracts of atmospheric particulate matters (PMs) are still not well characterized by in vitro toxicoproteomics. In this study, in vitro cytotoxicity assays and toxicoproteomic analyses were carried out to investigate toxic effects of PM collected using polytetrafluoroethylene (PTFE) filters extracted with acetone for PM2.1 and water for PM2.1 and PM10 on A549 human lung epithelial cells. The cytotoxicity assays based on cell viability, cell apoptosis and reactive oxygen species generation indicated that PM2.1 extracted with acetone had the highest toxicity. iTRAQ labeling and LC-MS/MS analyses indicated that the number of differentially expressed proteins in A549 cells affected by PM2.1 extracted with acetone was noticeably higher than that of the other two groups. Hierarchical cluster analyses showed that the influences of the extracts of PM2.1 and PM10 using water on the proteome of A549 cells were similar, whereas significantly different from the effect of PM2.1 extracted with acetone. Pathways analyses indicated that PM2.1 extracted with acetone influenced the expression of proteins involved in 14 pathways including glycolysis/gluconeogenesis, pentose phosphate pathway, proteasome, etc. PM2.1 extracted with water affected the expression of proteins involved in 3 pathways including non-homologous end-joining, ribosome and endocytosis. However, PM10 extracted with water affected the expression of proteins involved in only spliceosome pathway. The extracts of PM using different extractants to detach PM from PTFE filters influenced the cytotoxic effects of PM and the proteome of A549 cells. Therefore, extractants should be assessed carefully before the investigations on cytotoxicity to improve the compatibility of experimental results among research teams.

[Studies on the chemical constituents of Salvia miltiorrhiz of Lijiang].

OBJECTIVE: To study chemical constituents of Salvia miltiorrhiz of Lijiang. METHODS: The constituents were separated and purified by column chromatography with silica gel. Their structures were identified on the basis of physical and spectral data. RESULTS: Eleven compounds were isolated and identified as: (1) ferlalic acid; (2) O-hydroxybenzoic acid; (3) protocatechualdehyde; (4) beta-3,4-dihydroxyphenyl-lactic acid; (5) ursolic acid; (6) 6,7-dimethoxy-5,4'-dihydroxy-flavonol-3-O-glucoside; (7) carnosol; (8) tanshinone II(A); (9) tanshinone I; (10) 5,6-dehydrosugiol; (11) crypotanshinone.