| 研究実績の概要 |
Ozone has a very high oxidative activity with a concentration of a few tens of ppb in the ambient air. During breathing, the lipids and the cells in one’s respiratory system are hard to avoid the oxidative effect of ozone. Here, by exposing the lipid of lung surfactant and the human alveolar epithelial cells to the ambient ozone of a low concentration (20-100 ppb), we systematically studied the lipid oxidation through high resolution LC-MS/MS.
The lipid monolayers composed by DPPC, POPC and POPG were used as the model system of the lung surfactant. Their stability and ozonized products were successfully identified and quantified. By mixing with cholesterol, we observed the physicochemical properties of the lipid membrane strongly influenced the yield of certain ozonation products. Furthermore, we found a phenolic compound 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA) strongly inhabited the oxidation process.
In addition, we established a novel lipidomics method and successfully applied it to study the ozonation of the adenocarcinomic human alveolar basal epithelial cell (A549). We found the aldehyde-type ozonized lipids are the major products. More importantly, the secondary ozonides (SOZ) with the head group of phosphocholine were also identified as the products and its amount is related to the relative humility of the air.
Our study gave a molecular-level view of the effect of the ambient ozone on the lipids in the lung. The novel lipidomics method has great potential for searching the biomarker of the lung damage in the low-concentration air pollutant.
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