Ecotoxicology and Environmental Safety (Jan 2023)

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

  • Peiyu Guo,
  • MingJun Lei,
  • Sai Hu,
  • Zi Xu,
  • Yao Zhou,
  • Pingkun Zhou,
  • Ruixue Huang

Journal volume & issue
Vol. 249
p. 114351

Abstract

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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.

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