Citral mitigates inflammation of Caco-2 cells induced by Cronobacter sakazakii

Abstract

The aim of this study was to explore the anti-inflammatory effect and mechanism of citral in Cronobacter sakazakii-stimulated Caco-2 cells. Safe doses of citral were first determined in Caco-2 cells. Then, the effect of citral on the adhesion and invasion of C. sakazakii into Caco-2 cells and the translocation of C. sakazakii through Caco-2 monolayers were investigated. The release of nitric oxide (NO), interleukin (IL)-1β, IL-6, and TNF-α, transcription of inflammatory genes, and expression of proteins associated with inflammatory signaling pathways were determined. Subsequently, activation of caspase-3, -8, and -9 and apoptosis induced by C. sakazakii were assessed. The results showed that up to 10 μg mL⁻¹ citral had no cytotoxicity in Caco-2 cells. Citral protected Caco-2 cells by affecting the adhesion and invasion of C. sakazakii into Caco-2 cells and the translocation of C. sakazakii across Caco-2 monolayers. Additionally, inflammation induced by C. sakazakii was effectively inhibited by citral via suppression of inflammatory factors that included NO, IL-1β, IL-6, and TNF-α, transcription of related genes, and expression of proteins associated with inflammatory signaling pathways. Moreover, the activation of caspase-3, -8, and -9, and apoptosis caused by C. sakazakii were suppressed by pretreatment with citral. These findings suggest that citral mitigates the inflammatory response of Caco-2 cells. Citral has the potential to prevent the inflammation of Caco-2 associated with C. sakazakii.