Metabolomic analysis of the brain and blood from rats exposed to high-dose chlorpyrifos

Chlorpyrifos is an organophosphate pesticide used to kill pests such as insects and worms. Wide use of chlorpyrifos has led to serious safety concerns worldwide. Research on the mechanism of action of chlorpyrifos poisoning is continuing. We investigated changes in the small-molecular metabolites in the brain and blood of rats upon exposure to chlorpyrifos at an acute-poisoning dose. Rats were given twice the lowest dose of chlorpyrifos that is lethal for 100% of exposed animals (2 × LD100) and then killed after 2 h. After treatment, gas chromatography-mass spectrometry was used to analyze the metabolomic changes in the brain and blood samples of rats. An increase in blood levels of creatinine and uric acid were noted, along with a decrease in levels of various amino acids. These changes suggested that chlorpyrifos exposure may damage kidney function and cause disorders in amino-acid metabolism of rats. Decreased concentrations of gamma-aminobutyric acid and niacinamide in the brain and increased concentrations of 3-hydroxybutyric acid in rats with acute poisoning by chlorpyrifos were observed, which may suggest oxidative damage in the body.