Aflatoxin B1-activated heterophil extracellular traps result in the immunotoxicity to liver and kidney in chickens

Abstract

Aflatoxin B1 (AFB1) is a mycotoxin with strong toxicity and play a large proportion in aspergillosis. Heterophil extracellular traps (HETs) was considered as an innate immune response of chickens to resist pathogens. AFB1 has been reported to trigger macrophages extracellular traps (METs) in THP-1 cells and RAW264.7 cells, but whether AFB1 could also activate HETs release, and the mechanism underlying AFB1-activated HETs in chicken remains unclear. In this study, we confirmed that AFB1could induce HETs release, which was a network of DNA-based structures consist of citrullinated histone 3 (citH3) and elastase. Meanwhile, AFB1-activated HETs rely on the glycolytic process to provide energy, NADPH oxidase and p38 signaling pathway. Moreover, it has been verified that AFB1-activated HETs release could significantly increase the biochemical indexes of liver (ALT and AST) and kidney (CRE and BUN) in serum. In addition, histopathological observation showed that AFB1 caused swelling, necrosis and vacuolation of hepatocytes in liver, and necrosis, exfoliated of nephrocyte in kidney. Further investigation demonstrated that AFB1 significantly decreased the levels of SOD and GSH-PX but increased the level of MDA, and meanwhile induced the mRNA expressions of TNF-α, IL-6 and IL-1β, iNOS, COX-2, NLRP3, caspase-1, caspase-3 and caspase-11. However, all these AFB1-induced biochemical indexes and histopathological changes were effectively alleviated by DNase I (the standard degradant for HETs). In conclusion, it has preliminary confirmed that AFB1-activated HETs formation contributed to the immunotoxicity in chicken and provide new strategies for the therapy in aspergillosis.

Keywords: Aflatoxin B1; Chicken; Heterophil extracellular traps; Immunotoxicity; Liver.