Alanyl-glutamine Ameliorates Lipopolysaccharide-induced Inflammation and Barrier Function Injury in Bovine Jejunum Epithelial Cells

The aim of this study was to investigate the effects of alanyl-glutamine (Ala-Gln) on the regulation of lipopolysaccharide (LPS)-induced inflammation and barrier function in bovine jejunum epithelial cells (BJECs). BJECs were exposed (or not) to 1 μg/mL LPS for 24 h to generate a pro-inflammatory model. The cells were then treated with different concentrations of Ala-Gln (0.25, 0.5, 1.0, 2.0, or 4.0 mmol/L) to detect any regulatory effects on the inflammation and barrier function of BJECs. LPS decreased cell viability and enhanced the production of the pro-inflammatory cytokines interleukin (IL)-6 and IL-8. LPS induced inflammation and damaged the barrier function of BJECs, as evidenced by up-regulated mRNA and protein expression of inflammatory factors and down-regulated expression of tight junction proteins. Conversely, Ala-Gln rescued the decrease in cell viability and prevented the accumulation of ILs after LPS exposure by reducing the mRNA and protein expression levels of inflammatory factors. In addition, Ala-Gln induced the mRNA and protein expression of multiple tight junction proteins, and thus reconstituted the barrier function of BJECs. In conclusion, Ala-Gln attenuates injury from inflammation and repairs damaged intestinal barrier induced with LPS, suggesting its potential as a therapeutic agent against intestinal inflammation in mammals.