Lipid Peroxidation and Antioxidant Defenses According to Severity of PQ Poisoning

ABSTRACT

PURPOSE: Paraquat (PQ) increases the level of toxic reactive oxygen species in humans. Various endogenous antioxidant mechanisms against PQ exist in humans. The aim of the present study was to assess lipid peroxidation and antioxidative defenses of humans exposed to acute PQ poisoning over time. METHODS: The medical records of patients who presented to the emergency department (ED) within 6 hours after PQ poisoning were reviewed. Patients were classified into three groups based on the severity index of paraquat poisoning (SIPP) using the serum level of PQ and time interval from exposure to ED arrival. The serum level of malondialdehyde (MDA) and the activities of antioxidative enzymes were compared between groups at baseline, 12 hours, 24 hours and 48 hours after presentation. RESULTS: The mean age of enrolled patients was 51.0+/-15.9 years and they ingested 143.3+/-144.4 ml of 24.5% liquid PQ accidently or as an attempted suicide. The baseline MDA level, and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the three groups were similar. In the SIPP >50 group, the serum MDA level and the SOD activity significantly increased from baseline, peaking at 24 hours. In the 10< or =SIPP< or =50 group, serum MDA level and SOD activity displayed a smooth and steady increase. In the SIPP <10 group, serum MDA level steadily decreased but SOD activity increased. GPx activity did not show any changes. CONCLUSION: PQ changes serum levels of MDA and SOD activity depending on the severity of PQ intoxication, but serum GPx activity does not significantly change.