Lactobacillus rhamnosus GG alleviates radiation-induced intestinal injury by modulating intestinal immunity and remodeling gut microbiota.

Radiation injury to the intestine is one of the most common complications in patients undergoing abdominal or pelvic cavity radiotherapy. In this study, we investigated the potential protective effect of Lactobacillus rhamnosus GG (LGG) on radiation-induced intestinal injury and its underlying mechanisms. Mice were assigned to a control group, a 10 Gy total abdominal irradiation (TAI) group, or a group pretreated with 108 CFU LGG for three days before TAI. Small intestine and gut microbiota were analyzed 3.5 days post-exposure. LGG intervention improved intestinal structure, reduced jejunal DNA damage, and inhibited the inflammatory cGAS/STING pathway. Furthermore, LGG reduced M1 proinflammatory macrophage and CD8+ T cell infiltration, restoring the balance between Th17 and Treg cells in the inflamed jejunum. LGG also partially restored the gut microbiota. These findings suggest the possible therapeutic radioprotective effect of probiotics LGG in alleviating radiation-induced intestinal injury by maintaining immune homeostasis and reshaping gut microbiota. [Display omitted] • Radiation induces intestinal injury by impairing immune balance and gut microbiota. • Lactobacillus rhamnosus GG (LGG) improves intestinal structure and permeability. • LGG inhibits the activation of the inflammatory-related cGAS/STING pathway. • LGG reduces M1 macrophage and restores Th17/Treg cell balance in inflamed jejunum. • LGG regulates intestinal immunity by remodeling the gut microbiota. [ABSTRACT FROM AUTHOR]