Oxidative Stress in Early Stage of Acute Lung Injury Induced with Oleic Acid in Guinea Pigs

Changes in several biomarkers in bronchoalveolar lavage fluid (BALF) during an early stage of lung injury induced with oleic acid were examined in guinea pigs. In addition, a possible contribution of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and xanthine oxidase to the oxidative changes in the lung injury was investigated. An intravenous injection of oleic acid increased the levels of lipid peroxidation products, lactate dehydrogenase, and total proteins, decreased the ratio of glutathione to glutathione disulfide in the BALF, and also affected the levels of other oxidative biomarkers such as superoxide dismutase and catalase in the BALF in a dose-dependent manner. Diphenyleneiodonium chloride, a NADPH oxidase inhibitor, inhibited the oxidative changes in the BALF and the decrease in partial pressure of oxygen in artery induced with oleic acid, while allopurinol, a xanthine oxidase inhibitor, had no inhibitory effects. The results demonstrate that oxidative stress would be an important mechanism of oleic acid-induced lung injury, and indicate that the NADPH oxidase-dependent pathway contributes significantly to the generation of reactive oxygen species in oleic acid-induced lung injury.