Protective effect of ethyl pyruvate on gut barrier function through regulations of ROS-related NETs formation during sepsis.

Background: Sepsis impairs the function of the intestinal barrier through neutrophil extracellular traps (NETs). Reactive oxygen species (ROS)-induced activation of mitogen-activated protein kinase (MAPK) is involved in NET formation. Ethyl pyruvate (EP), a potent and effective ROS scavenger, ameliorates sepsis-associated intestinal barrier dysfunction, but the detailed mechanism is unknown. The current study aimed to explore the eff ;ects of EP on sepsis-induced intestinal barrier dysfunction and whether ROS and NETs were involved.

Methods: A sepsis model was induced in mice by intraperitoneal injection of LPS (10 mg/kg). The mice were divided into 4 groups: (1) sham group; (2) LPS group; (3) DNase-1 + LPS group; and (4) EP + LPS group. EP or DNase-1 was intraperitoneally injected after the LPS model was established. After 24 h, the small intestine and blood were collected for analysis. Human neutrophils were harvested and incubated with phorbol-12-myristate-13-acetate (PMA) or PMA + EP, and ROS and NET generation was measured.

Results: EP significantly decreased proinflammatory cytokines and MPO-DNA in the LPS model. In addition, EP suppressed NET formation in the intestines of endotoxemic mice. The decrease in NETs induced by EP or DNase-1 alleviated histopathological damage, intestinal cell apoptosis and increased tight junction expression. In vitro, the treatment of EP abolished PMA-induced ROS production and NET formation which could be reversed by HO treatment. Meanwhile, EP also abolished MAPK ERK1/2 and p38 activation during PMA-induced NET formation.

Conclusion: This study was the first to demonstrate that EP alleviated NET formation and sepsis-induced intestinal damage through blockage of ROS mediated MAPK ERK1/2 and p38 activation.