Abstract
BackgroundAcute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are critical life-threatening syndromes characterized by the infiltration of a large number of granulocytes (mainly neutrophils) that lead to an excessive inflammatory response. Emodin (Emo) is a naturally occurring anthraquinone derivative and an active ingredient of Chinese medicine. It is believed to have anti-inflammatory effects. In this study, we examined the impact of Emo on the pulmonary inflammatory response and the granulocytes function in a rat model of lipopolysaccharide (LPS)-induced ALI.ResultsTreatment with Emo protected rat against LPS-induced ALI. Compared to untreated rat, Emo-treated rat exhibited significantly ameliorated lung pathological changes and decreased tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). However, Emo has no protective effect on the rat model of acute lung injury with granulocyte deficiency. In addition, treatment with Emo enhanced the bactericidal capacity of LPS-induced granulocytes via the up-regulation of the ability of granulocytes to phagocytize bacteria and generate neutrophil extracellular traps (NETs). Emo also downregulated the respiratory burst and the expression of reactive oxygen species (ROS) in LPS-stimulated granulocytes, alleviating the damage of granulocytes to surrounding tissues. Finally, Emo can accelerate the resolution of inflammation by promoting apoptosis of granulocytes.ConclusionOur results provide the evidence that Emo could ameliorates LPS-induced ALI via its anti-inflammatory action by modulating the function of granulocytes. Emo may be a promising preventive and therapeutic agent in the treatment of ALI.
Highlights
Acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are critical life-threatening syndromes characterized by the infiltration of a large number of granulocytes that lead to an excessive inflammatory response
Our study found that phorbol ester (PMA) stimulates granulocytes to produce the most neutrophil extracellular traps (NETs) compared with IL-8, LPS and formyl methionyl leucyl phenylalanine (fMLP) (P < 0.01) (Fig. 4b)
We found that the average fluorescence intensity of granulocytes phagocytosis of pHrodo green S.aureus increased from 2749.44 ± 469.95 at 30 min to 12,305.01 ± 1425.02 at 60 min (P < 0.01) (Fig. 5a)
Summary
Acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are critical life-threatening syndromes characterized by the infiltration of a large number of granulocytes (mainly neutrophils) that lead to an excessive inflammatory response. Lipopolysaccharide (LPS), an important component of the outer membrane of Gram-negative bacteria, is Granulocytes are the most abundant white blood cells, including neutrophils, eosinophils and basophils, most of which are neutrophils. They are essential for killing bacteria and other microorganisms, and they have a significant role in regulating the inflammatory response. In order to exert its bactericidal function, circulating granulocytes first follow the chemokine gradient to the inflammatory site They kill the pathogenic microorganisms through mechanisms, such as phagocytosis, Mei et al Journal of Inflammation (2020) 17:26 secretion of germicidal particles and neutrophil extracellular traps (NETs)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
