Luteolin attenuates the pulmonary inflammatory response involves abilities of antioxidation and inhibition of MAPK and NFκB pathways in mice with endotoxin-induced acute lung injury

Acute lung injury (ALI) in critically ill patients remains the leading cause of mortality and morbidity. Lipopolysaccharide (LPS) is a key mediator of lung injury. This study investigates the protective effects and mechanisms of luteolin in intratracheal instillation of LPS (100μg)-induced ALI in mice. Pretreatment of mice with 70μmol/kg luteolin significantly restores LPS-induced decrease in oxygen pressure and increase in carbon dioxide in arterial blood. The histopathological study established 70μmol/kg luteolin pretreatment markedly attenuates lung histopathological changes, such as haemorrhaging, interstitial edema, and infiltration of polymorphonuclear neutrophils (PMNs) into the lung parenchyma and alveolar spaces. Sufficient evidence for luteolin (35 and 70μmol/kg) suppresses activation and infiltration of PMNs is obtained in expression of surface marker CD11b and Ly6G on cells in bronchoalveolar lavage fluid (BALF) cells and myeloperoxidase activity in lung tissue. Furthermore, luteolin reduces the activity of catalase and superoxide dismutase, and the level of oxidative damage, and lipid peroxidation, in lung tissue. In addition, the secretion of TNF-α, KC, and ICAM-1 in the BALF after LPS challenge are also inhibited by luteolin. Moreover, luteolin reduced LPS-induced activation of MAPK and NFκB pathways. Therefore, luteolin is a potential protective antagonists for LPS-induced ALI in mice.