The effects of Lactobacillus reuteri microcapsules on radiation-induced brain injury by regulating the gut microenvironment

A radiation-induced brain injury (RIBI) is a major adverse event following radiotherapy of malignant tumors. RIBI would affect cognitive function, leading to a series of complications and even death. However, the pathogenesis of RIBI is still unclear, and it still lacks specific therapeutic drugs. The gut-brain bidirectional communication may be mediated by various microbiota and metabolites in the gastrointestinal tract. Probiotics are closely related to physiological health. The theory of the gut-brain axis provides us with a new idea to improve the gut microenvironment by supplementing probiotics against RIBI. Here, Lactobacillus reuteri microcapsules (LMCs) were prepared, which were predominantly irregular spheres with a rough surface under a scanning electron microscope and a narrow size distribution ranging from 20 to 700 mu m. The transmission electron microscopy images showed that the structure of microcapsules containing Lactobacillus reuteri (L. reuteri) was a core and shell structure. The survival of L. reuteri in microcapsules was significantly more than that of free L. reuteri in the simulated stomach environment of pH 1.2. 16S rDNA sequencing showed that LMCs observably increased the relative abundance of Lactobacillus in RIBI mice. More importantly, compared with the RIBI model mice, the behavior of RIBI mice treated with LMCs was significantly improved. In addition, LMCs greatly alleviated the pathological damage of the hippocampus and intestines in the mice after irradiation and reduced the level of TNF-alpha and IL-6 in vivo. Generally, LMCs are a promising oral preparation, which provide new ideas and methods for the treatment of RIBI.

Automated summary

This study demonstrates that supplementation of probiotics can improve the gut microenvironment and alleviate the cognitive impairment caused by radiation-induced brain injury (RIBI). Microcapsules containing Lactobacillus reuteri (L. reuteri) were prepared, which significantly enhanced the survival of L. reuteri in the harsh stomach environment. The treatment with L. reuteri microcapsules improved the behavior of RIBI mice and reduced pathological damage in the hippocampus and intestines, as well as decreased the levels of TNF-alpha and IL-6.