Long-term LDR exposure may induce cognitive impairments: A possible association through targeting gut microbiota-gut-brain axis

• Published in: Ecotoxicology and environmental safety 2023-01, Vol.249, p.114351, Article 114351
• Main Authors: Guo, Peiyu, Lei, MingJun, Hu, Sai, Xu, Zi, Zhou, Yao, Zhou, Pingkun, Huang, Ruixue
• Format: Article
• Language: English
• Subjects: Animals; Brain-Gut Axis - radiation effects; Cognitive Dysfunction - etiology; Cognitive impairment; Dose-Response Relationship, Radiation; Gastrointestinal Microbiome - radiation effects; Gut microbiota; Intestinal barrier; Lipopolysaccharides - metabolism; Lipopolysaccharides - radiation effects; Low-dose radiation; Male; Mice; Mice, Inbred C57BL; Radiation Exposure; Radiation Injuries; SCFAs
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2022.114351

Environmental and occupational low-dose radiation (LDR) exposure may be harmful for health but the previous reports regarding effect of LDR on cognition are contradictory. Here we investigated the effect of long-term LDR exposure on cognition. In this study, male Balb/c mice’ cognitive functions were tested at 15 weeks after being exposed to 0.5 Gy LDR in 10 fractions at each dose of 0.05 Gy. The results demonstrated that long-term LDR exposure increases escape latency and the time spent in finding exits in mice compared with non LDR exposure. Meanwhile, the inflammation-related proteins including NFκB and p38 also increased. Lipopolysaccharide (LPS) increased and short-chain fatty acid (SCFA) levels decreased following long term LDR exposure. Treatment with microbiota-derived LPS and SCFAs reversed these effects in mice. Furthermore, the gut barrier integrity was damaged in a time-dependent manner with the decreased expression of intestinal epithelial-related biomarkers such as ZO-1 and occludin. Mechanistically, long after exposure to LDR, increased LPS levels may cause cognitive impairment through the regulation of Akt/mTOR signaling in the mouse hippocampus. These findings provide new insight into the clinical applications of LDR and suggest that the gut microbiota–plasma LPS and SCFAs–brain axis may underlie long-term LDR-induced cognition effects. •Long after exposure to low dose radiation (LDR) may cause cognitive impairment.•Long after exposure to LDR increased LPS levels.•Akt/mTOR insulin signaling may be associated with LDR-related cognitive impairment.