Probiotic bacteria induced improvement of the mucosal integrity of enterocyte-like Caco-2 cells after exposure to Salmonella enteritidis 857

Probiotics protect the intestinal epithelium. Whether their protection against Salmonella is mediated via stabilizing the barrier integrity was examined here. The intestinal barrier integrity was assessed by measuring the trans-epithelial electrical resistance (TER) of Caco-2 cell monolayer. Cells were exposed for 1 h to Lactobacillus casei W56, Lactobacillus salivarius W24, Lactobacillus acidophilus W70, Lactococcus lactis W58, Bifidobacterium infantis W52 or Bifidobacterium bifidum W23 at 200 bacteria/cell or to Salmonella enteritidis 857 at 1–200 bacteria/cell or to a combination of either of the probiotic and Salmonella both at 200 bacteria/cell. Heat shock protein (Hsp) 70 was assessed by Western blotting. Probiotics induced a significant increase while Salmonella decreased the TER. The latter was attenuated by probiotics but without full recovery. In addition, probiotics induced over-expression of Hsp70. It may be concluded that probiotics stabilise the intestinal integrity and impede Salmonella infection via, at least in part, production of Hsp70.