Early detection of ozone-induced hydroperoxides in epithelial cells by a novel infrared spectroscopic method

In the lower atmosphere ozone is a toxic and an unwanted oxidising pollutan t causing injury to the airway epithelial cells by lipid peroxidation to yi eld products such as phospholipid hydroperoxides (PLHP). Measurements of PL HP, which are primary oxidation products, may reflect an early susceptibili ty of the target cell to oxidative stress. Biphasic cultures of bronchial e pithelial cells (BEAS-28) were exposed to ozone at environmentally relevant concentrations (0.1-1.0 ppm) for 4 and 12 h. Detection of PLHP was made us ing a novel technique based on fourier transform infrared spectroscopy (FTI R) in combination with high performance thin-layer chromatography (HPTLC). Six phospholipids were identified on the HPTLC plate; lysophosphatidylcholi ne (LPC), sphingomyelin (SM), phosphatidylcholine (PC), lysophosphatidyleth anolamine (LPE), phosphatidylinositol (PI), and phosphatidylethanolamine (P E). From the FTIR spectra, O-O stretching of hydroperoxides was identified in the range 890-820 cm(-1) Multivariate data analysis revealed a positive correlation (r = 0.99 for 4 h exposure and r = 0.98 for 12 h exposure) betw een ozone exposure levels and the region of the FTIR-spectrum comprising th e main wavelengths for hydroperoxides. These data support this alternative, versatile and novel spectroscopic approach for the early detection of ozon e mediated damage in human airway epithelial cells.