Lactobacillus rhamnosus GG is the most studied and well-characterized probiotic strain, it was patented 30 years ago. It produces lactic acid, it ferments rhamnose. It is able to survive to gastric acidity and bile salts, to adhere to the intestinal mucosa, it modulates the immune system and epithelial cells apoptosis.

LGG exerts numerous beneficial functions on the host health, especially contributing to the intestinal well-being and homeostasis, through different mechanisms.

Firstly, LGG protect the gut from inflammation, as shown in the following study, where we can observe that, in an induced colitis model, LGG treatment significantly reduces the levels of pro-inflammatory cytokines, in colons (Yan et al., 2017).

At intestinal level, LGG is also able to increase the antioxidant defence system and reduce the oxidative damage to DNA, as shown in the work of Liu and colleagues (2021). In the following graphs, three parameters are considered: Superoxide dismutase (SOD) is an important component of the antioxidant defense system, Glutathione peroxidase (GPX) family is a major member of the antioxidant enzyme family, GPX4 is one of its parts. Moreover, it was evaluated oxidative damage to DNA by immunohistochemistry monitoring of γ-H2AX. We can observe that in absence of LGG the expression of antioxidant enzymes is significantly reduced compared to the condition where we have LGG colonization of the gut and, in parallel, the oxidative damage to DNA is, of course, affected.

Moreover, LGG contributes to the maintenance of the intestinal barrier function, exerting different activities: it stimulates the expression of the intestinal tight junction proteins, it maintains the proper distribution of them, also when the intestinal epithelium is stressed by inflammation, and it stimulates the production of short chain fatty acids, which are fundamental to regulate intestinal homeostasis.

References 

Liu, T., Song, X., An, Y., Wu, X., Zhang, W., Li, J., … & Cao, H. (2021). Lactobacillus rhamnosus GG colonization in early life ameliorates inflammaging of offspring by activating SIRT1/AMPK/PGC-1α pathway. Oxidative Medicine and Cellular Longevity, 2021.

Yan, F., Liu, L., Cao, H., Moore, D. J., Washington, M. K., Wang, B., … & Polk, D. B. (2017). Neonatal colonization of mice with LGG promotes intestinal development and decreases susceptibility to colitis in adulthood. Mucosal Immunology, 10(1), 117-127.