Clinical injury factors of neonatal ARDS are mainly divided into two categories. Direct injury factors include inhalation of meconium and bloody amniotic fluid, milk aspiration, severe pulmonary infection, pulmonary hemorrhage, hyperoxia, ventilator‑associated lung injury, etc. Indirect injury factors contain perinatal asphyxia, sepsis, necrotizing enterocolitis, cold injury, massive blood transfusion, surgical trauma and other conditions. Among them, sepsis is the most common cause of neonatal acute lung injury. Bacterial endotoxin, as a natural pathogenic factor, serves as a critical inducer of ARDS. Therefore, endotoxin (LPS) is widely adopted to establish animal models of neonatal ARDS in most studies. Endotoxin, namely lipopolysaccharide (LPS), is a toxic product derived from bacteria, with its toxicity mainly mediated by lipid A. Circulating LPS binds to lipopolysaccharide-binding protein in plasma. The resultant complex further activates CD14/TLR4 receptors on monocytes, macrophages and other immune cells, thereby triggering the massive release of inflammatory mediators.

Neonatal SD rats
Modeling method: Intraperitoneal injection of LPS for 2 consecutive days to establish a neonatal respiratory distress model.
Evaluation indicators: wet/dry weight ratio of organs, biochemical detection and HE staining.

Lung wet-to-dry weight ratio and biochemical detection

Lung tissue HE staining