Previous studies had found the strains Lactobacillus rhamnosus GG (LGG) and Lactobacillus reuteri ZJ617 (ZJ617) are effective in reducing gut inflammation and permeability.
Based on this, researchers from Zhejiang University sought to determine how LGG and ZJ617 could alleviate lipopolysaccharide-induced barrier dysfunction of the ileum (part of the intestine).
They divided six- to eight-week old mice into groups of six, then orally inoculated the mice in one group with LGG and the mice in the other with ZJ617 for one week while the control groups received injections containing sterile phosphate-buffered saline (PBS).
They then administered intraperitoneal lipopolysaccharide injections to the mice to induce intestinal barrier dysfunction.
After 24 hours, the researchers observed that pre-treatment with either of the live probiotic strains had helped to attenuate any lipopolysaccharide-induced intestinal permeability.
In addition, the probiotic supplementation also suppressed lipopolysaccharide-induced oxidative stress, and “strongly reversed the decline of occludin and claudin-3 (transcellular proteins) expression” caused by lipopolysaccharides.
The researchers subsequently found that ZJ617 alleviated lipopolysaccharide-induced apoptosis by restricting caspase-3 activity, which leads to increased permeability of the epithelial barrier.
They also wrote: “Taken together, these results indicate that ZJ617 and LGG protect the intestinal epithelial tight junctions (TJ) and the barrier function from lipopolysaccharide-induced insult by restoration of TJ protein expression and maintenance of TJ structure.”
They concluded that “these findings could serve as systematic mechanisms through which probiotics promote and maintain gut homeostasis”.