Butyrate alleviates food allergy by improving intestinal barrier integrity through suppressing oxidative stress-mediated Notch signaling.

Food allergy (FA) has received increased attention in recent years. Multiple studies have highlighted the crucial role of short-chain fatty acids (SCFAs) in the development of IgE-mediated FA. Here, a case-control approach was employed to analyze SCFAs profiles in children with FA, while an ovalbumin (OVA)-sensitized mouse model was utilized to explore the underlying mechanism by which SCFAs mitigate FA. Children with food-sensitized tolerance (FST) (n = 20) or FA (n = 20), and healthy controls (HC) (n = 20) were recruited to analyze SCFAs profiles. The HC group exhibited higher SCFAs levels in fecal samples than the FST, FA, and FST + FA groups. Data from an OVA-sensitized mouse model showed that butyrate exhibited a more significant effect on reducing allergic reactions compared to other SCFAs. Compared to the negative control group, OVA-induced oxidative stress (OS) triggered excessive Notch signaling activation, which subsequently impaired both tight junctions integrity and mucosal barrier function in murine intestinal epithelial cells (IECs). Gut dysbiosis induced mucus layer erosion, thereby elevating IECs exposure to food antigens and OS, which potentiated Notch signaling activation. However, butyrate counteracted this loop by restoring microbiota structure and suppressing reactive oxygen species (ROS)/Notch cascades. Strikingly, low-dose butyrate (0.25-1 mM) protected rat small intestine crypt epithelial cells (IEC-6) by inhibiting ROS, whereas high-dose (2-5 mM) exacerbated oxidative injury and triggered activation of Notch signaling. Our study revealed the potential molecular mechanisms through which butyrate alleviates food allergy, providing a potential therapeutic strategy for its management.