The combined effect of deoxynivalenol and Fumonisin B1 on small intestinal inflammation mediated by pyroptosis in vivo and in vitro

Abstract

Currently, due to the actual contamination levels of multiple mycotoxins, the limits for a single mycotoxin may be no longer applicable. Deoxynivalenol (DON) and Fumonisin B₁ (FB₁) had high positive rate in grain and feed worldwide. The intestine is the first target of mycotoxins. NLRP3 plays a crucial role in the gut's defense against external stimuli, which contributes vitally to pyroptosis activation. However, whether pyroptosis is engaged in the regulation of intestinal toxicity induced by DON and FB₁ remains unclear. In this study, we explored the combined toxicity of DON and FB₁ on the intestine and its underlying mechanisms in vivo and in vitro. Our data demonstrated gavage with DON and FB₁ led to intestinal damage and promoted the secretion of pro-inflammatory cytokines (IL-1β, IL-18, IL-6) in mice, especially in the group exposed to both mycotoxins. Meanwhile, the expressions of pyroptosis related genes (NLRP3, ASC, caspase-1, GSDMD) were significantly increased after mycotoxins exposure. Same as in vivo, DON and FB₁ promoted pyroptosis and cellular inflammatory response in IPEC-J2 cells, especially in the group exposed to both mycotoxins. In addition, the pretreatment with MCC950 and VX765, inhibitors for NLRP3 and caspase-1, abolished the expression of GSDMD and the release of pro-inflammatory factors (IL-1β, IL-18) induced by DON and FB₁ exposure in IPEC-J2 cells. Our data demonstrated that the combination of DON and FB₁ exhibited a synergistic or additive effect in facilitating intestinal inflammation via pyroptosis. Our finding may contribute to improve mycotoxin limit standards in feed.

Keywords: Combined toxicity; Deoxynivalenol; Fumonisin B(1); Intestinal inflammation; NLRP3 inflammasome; Pyroptosis.