Effects of different probiotic strains B. lactis, L. rhamnosus and L. reuteri on brain-intestinal axis immunomodulation in an endotoxin-induced inflammation

The study evaluated the effects of supplementation with three different probiotic strains Bifidobacterium lactis (LACT GB™), Lactobacillus rhamnosus (RHAM GB™) and Lactobacillus reuteri (REUT GB™) on brain-intestinal immunomodulation in an animal model of LPS-induced inflammation. Fifty mice Balb/C were distributed into five groups: control; lipopolysaccharide (LPS); LPS + B. lactis (LACT GB™); LPS + L. rhamnosus (RHAM GB™); and LPS + L. reuteri (REUT GB™). The animals were supplemented with their respective probiotic microorganisms daily, for 30 days, at a concentration of 1 × 109 CFU/animal/day. After 30 days of supplementation, animals received the inflammatory insult by LPS (15 mg/kg). Behavioral tests, oxidative stress and inflammation were performed, as well as gut and brain histology. In the behavioral test, LPS + B. lactis group was less anxious than the other groups. Serum interleukin IL-1β and IL-6 levels increased in all groups that received the LPS insult, and there was a reduction in inflammation in the supplemented groups when compared to the LPS group in brain and gut. There is a reduction in myeloperoxidase activity and oxidative stress in groups supplemented with probiotics. In intestine histological analysis occurs damage to the tissue integrity in the LPS group, in the other hand, occurs preservation of integrity in the probiotic supplemented animals. In the brain, infiltrates of perivascular inflammatory cells can be seen in the LPS group. The three probiotic studies showed efficient immunomodulating activity and ensured integrity of the intestinal barrier function, even after the severe insult by LPS. These results show the important role of probiotics in the gut–brain axis. Graphical abstract illustratively represents the gut–brain axis and how different probiotic strains influence the immunomodulatory response releasing different pro- and anti-inflammatory cytokines, and their role in the balance of dysbiosis.