Effects of phospholipids from embryonated egg yolk on lipopolysaccharide-induced acute lung injury by regulating the serum metabolism

Acute lung injury is a severe and intricate condition characterized by the disruptions in the alveolar barrier, pulmonary edema, enhanced inflammation, and alveolar apoptosis. Existing therapeutic approaches often exhibit limited efficacy and undesirable side effects. Egg yolk phospholipids have shown some potential as nutritional supplements due to their anti-apoptotic and anti-inflammatory properties under various conditions. This study aimed to explore whether phospholipid supplementation, particularly those rich in phosphatidylcholine, could alleviate lipopolysaccharide-induced lung injury in mice. Mice received daily oral administrations of phospholipid extracts (800 mg/kg) from different sources (embryonated egg yolk on day 18 and unfertilized fresh egg yolk) for 7 days or a single dose of dexamethasone (positive control). Subsequently, lipopolysaccharide (10 mg/kg) was intraperitoneally injected, and the mice were euthanized after 6 h. Various samples were collected for histological examination, assessment of inflammation and oxidative stress, serum metabolome analysis, and identification of gut flora. Results demonstrated that pretreatment with phospholipids effectively mitigated damages to the alveolar-capillary barrier and reduced lung edema by suppressing the release of oxidative and inflammatory cytokines, with embryonated egg extracts exhibiting superior efficacy. Additionally, the protective mechanism of phospholipids seemed associated with the metabolic distribution and absorption, helping to maintain the right lipid metabolism and restore protein synthesis, thus mitigating the impact of lung injury. In conclusion, supplementation with phosphatidylcholine-enriched phospholipids may serve as an innovative nutritional strategy to alleviate the adverse effects of bacterial infection on alveolar function.