Oxysterols as indices of oxidative stress in man after paraquat ingestion

The aim of this study is to evaluate oxidative stress in man after paraquat ingestion by analyzing 7alpha- and 7beta-hydroperoxycholest-S-en-3beta-ol (7alpha- and 7beta-OOH) as well as oxysterols, cholesterol oxidation products, as indices of lipid peroxidation. Lung, kidney, and liver were collected at autopsy from seven patients with paraquat poisoning and seven controls matched for age and sex. We identified for the first time 7-ketocholesterol (7-keto) and 7-hydroxycholesterol (7alpha-OH and 7beta-OH) in human kidney by LC-MS. Next, we quantified 7alpha-OOH and 7beta-OOH by HPLC with postcolumn chemiluminescence as well as oxysterols by HPLC-UV. Both 7alpha-OOH and 7beta-OOH detected in lung and kidney from the controls were as low as the paraquat group. In contrast, we found both 7-keto and 7beta-OH in lung and 7-keto in kidney from the paraquat group were significantly higher than from the controls. This is the first report on accumulated oxysterols in lung and kidney from human paraquat poisoning. It seems to reflect greater oxidative stress in the pathology of paraquat intoxication.