AUTHOR=Zhou Qian , Shen Binhai , Huang Ruo , Liu Hongbin , Zhang Wendi , Song Mengyao , Liu Ke , Lin Xinlong , Chen Shuze , Liu Yangyang , Wang Ye , Zhi Fachao 

TITLE=Bacteroides fragilis strain ZY-312 promotes intestinal barrier integrity via upregulating the STAT3 pathway in a radiation-induced intestinal injury mouse model

JOURNAL=Frontiers in Nutrition

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.1063699

DOI=10.3389/fnut.2022.1063699

ISSN=2296-861X

ABSTRACT=<p>Radiation-induced intestinal injury is characterized by intestinal barrier impairment. However, the therapeutic effects of probiotics for intestinal epithelial barrier repair in a mouse model of radiation-induced intestinal injury remain unclear. Previously, we isolated a strain of <italic>Bacteroides fragilis</italic> from the feces of a healthy infant and named it as <italic>B. fragilis</italic> strain ZY-312 (<italic>B. fragilis</italic>). In this study, we showed that <italic>B. fragilis</italic> can ameliorate radiation-induced intestinal injury in mice, manifested by decreased weight loss, intestinal length shortening, and intestinal epithelial cell (IEC) shedding. Moreover, we found that <italic>B. fragilis</italic> promoted IEC proliferation, stem cell regeneration, mucus secretion, and tight junction integrity by upregulating the STAT3 signaling pathway, through an experimental verification in <italic>Stat3</italic><sup>△IEC</sup> mice (STAT3 defects in intestinal epithelial cells). Thus, the underlying protective mechanism of <italic>B. fragilis</italic> in radiation-induced intestinal injury is related to IEC proliferation, stem cell regeneration, goblet cell secretion, and tight junction repair <italic>via</italic> activation of the STAT3 signaling pathway. In addition, the therapeutic effects of <italic>B. fragilis</italic> were studied to provide new insights into its application as a functional and clinical drug for radiation-induced intestinal injury after radiotherapy.</p>