[Astragalus polysaccharide alleviates lipopolysaccharide-induced lung injury in rats by inhibiting neutrophil activation].

Objective To study the effects of Astragalus polysaccharide (APS) on rat lung injury induced by lipopolysaccharide (LPS). Methods A total of 36 adult SD rats were randomly divided into control group, LPS model group and APS administration group. Acute lung injury was induced by a single intratracheal injection of LPS. Lung injury in rats was observed by HE staining. The changes of proinflammatory factors such as tumor necrosis factor α (TNF-α) and interleukin 1ß (IL-1ß) were detected by ELISA. The numbers of white blood cells (WBCs) and neutrophils in bronchoalveolar lavage fluid (BALF) were determined by cell counting. The activity of myeloperoxidase (MPO) and reactive oxygen species (ROS) were tested by the respective kits. Results Compared with the control group, the LPS-induced model group showed pulmonary edema and increased vascular permeability, upregulated levels of TNF-α and IL-1ß in BALF, significantly ascended numbers of WBCs and neutrophils, enhanced MPO activity and increased ROS level. However, administration of APS suppressed LPS-induced vascular permeability, tissue injury and inflammation in the rat lung. APS also suppressed LPS-induced neutrophilic inflammation in BALF. MPO activity and ROS level decreased significantly as well. Conclusion Administration of APS suppresses LPS-induced lung injury via inhibiting of neutrophil activation in rats.