Effect of probiotic Lactobacillus acidophilus LA5 on protein expression related to intestinal barrier integrity in a model of periodontitis induced by Aggregatibacter actinomycetemcomitans

Abstract

Periodontitis is a chronic multifactorial inflammatory disease associated with a dysbiotic biofilm that leads to the progressive destruction of tooth support tissues, being one of the main causes of tooth loss. Previous in vitro and in vivo studies carried out in this laboratory have shown the potential of the probiotic strain Lactobacillus acidophilus LA5 to affect oral colonization and modulate the local and systemic immune response to the periodontal pathogen Porphyromonas gingivalis. We were also able to demonstrate that this strain is able to alter the expression of virulence factors of the periodontopathogen Aggregatibacter actinomycetemcomitans and to inhibit its adhesion to gingival epithelial cells and modify the response of these cells to the pathogen. Periodontitis is associated not only with oral dysbiosis, but also with intestinal dysbiosis, which is one of the mechanisms involved in systemic inflammation, since periodontal pathogens have been associated with greater intestinal permeability. This increase is due to reduced production of mucus and junction proteins (TJs). Studies in humans have shown changes in the intestinal microbiome in patients with aggressive periodontitis with high oral levels of A. actinomycetemcomitans, a pathogen able to produce a toxin similar to other diarrheogenic bacteria. The present study aims to test the hypothesis that the probiotic L. acidophilus LA5 is able to control the change in the intestinal epithelial barrier induced by the experimental oral inoculation of A. actinomycetemcomitans in a murine model. C57Bl/6 mice will be allocated into 4 groups, 12 animals per group: - Positive control, which will be infected with A. actinomycetemcomitans. Negative control: not infected. Probiotic Control: infected only with L. acidophilus LA5, and Experimental: Infected with A. actinomycetemcomitans and L. acidophilus LA5. After the 30-day experimental period, the animals will be euthanized and alveolar bone resorption will be determined by computadorized microtomography. The expression of genes associated with the permeability of the intestinal epithelial barrier will be evaluated by RT-qPCR, serum levels of LPS will be determined by the Limulus assay, and detection of A.actinomycetemcomitans in the gut and oral biofilms will be evaluated by quantitative PCR.