Terbuthylazine induces oxidative stress and mitophagy through activating cGAS-STING pathway in chicken jejunum

Abstract

Terbuthylazine (TBA) is a widely employed pesticide that has been found to be a significant source of food and environmental pollution. Excessive exposure to TBA raises considerable apprehension regarding its potential impact on biological health, but its underlying toxic mechanisms have not been reported. Our findings indicated that TBA exposure could cause intestinal damage, as evidenced by decrease in the quantity of cupped cells and decrease in the expression of intestinal barrier-related proteins (Claudin-1, Occludin, ZO-1, and JAM-1). Additionally, exposure to TBA resulted in a significant decrease in the expression levels of oxidative stress-related genes and proteins. Furthermore, the expression of 8-hydroxy-2′-deoxyguanosine was significantly upregulated. Additionally, excessive exposure to TBA led to a substantial release of mitochondrial DNA, which further activated the cGAS-STING pathway and caused TBK1 and IRF3 phosphorylation. Meanwhile, mitophagy was activated under TBA exposure, as evidenced by decrease in the protein and gene levels of p62 and increase in the levels of PINK1, PARKIN and LC3 II. Therefore, our results suggested that TBA exposure induced oxidative stress in the jejunum and caused mtDNA leakage, for activating the cGAS-STING pathway, which in turn promoted mitophagy. These findings revealed the toxicity mechanisms of TBA, which provided new insights into food safety caused by pesticide contamination.