Alumina nanoparticles-induced heterophil extracellular traps exacerbate liver injury by regulating oxidative stress and inflammation in chickens.

Widely used alumina nanoparticles (Al2O3 NPs) exposed to the environment pose a serious threat to human and animal health. The formation of heterophil extracellular traps (HETs) is a mechanism of innate immune defense against infection, but excessive HETs cause pathological damage. Here, we aim to explore the influence and mechanism of Al2O3 NPs on the formation of HETs in vitro, and further investigate the role of HETs release in histopathological damage after Al2O3 NPs treatment. Immunofluorescence analysis showed that Al2O3 NPs induced the formation of HETs, which was characterized by modified histones and elastase in the DNA backbone. Fluorescence microplate analysis showed that HETs formation was dependent on NADPH oxidase, P38, extracellular regulated protein kinases (ERK1/2) pathways and glycolysis. In vivo investigation showed that Al2O3 NPs significantly caused HETs release and liver damage. Biochemical analysis showed that Al2O3 NPs inhibited the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). Real-time fluorescence quantification results showed that Al2O3 NPs caused the overexpression of inflammation-related molecules interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), caspase-1 and caspase-11. All these changes were significantly changed by DNase I (Degradation reagent for HETs). Together, these suggest that Al2O3 NPs-induced HETs exacerbate liver injury by regulating oxidative stress and inflammatory responses, which provide a new perspective and potential prophylaxis and treatment targets for Al2O3 NPs toxicological research.