Summary of - Effects of low dose ionizing radiation on the brain- a functional, cellular, and molecular perspective

Document Type

Article

Abstract

The effects of low-dose radiation (≤ 0.1 Gy) (LDR) on the brain are variable and inconclusive. LDR exposure can lead to reduced neuronal proliferation, altered neurogenesis, neuroinflammation, and various neurological complications. The brain, particularly the developing brain, is exceptionally radiosensitive and more liable to neurological insult, even at low doses.

  • LDR exposure can cause negative dose-response in cognitive tests and human learning ability.
  • LDR can induce inflammatory responses, activate interferons and insulin-like growth factors, and suppress cell adhesion.
  • LDR can cause cellular stress responses, including morphological dystrophy, abnormal levels of essential enzymes or proteins, and activation of various signaling pathways.
  • LDR exposure can upregulate synaptic plasticity, ion transmembrane transport, dendrite development, and downregulated genes involved in ion transport, membrane potential, and cell-cell signaling. Proteomic analysis revealed similar changes, with up-regulated proteins involved in synaptic signaling and down-regulated proteins involved in cellular processes.

Objectives

The objective of the review is to summarize the current understanding of the effects of LDR on the brain at functional, cellular, and molecular levels and to address the knowledge gap about the effects of LDR on different pathological, genetic, and molecular aspects of the brain.

Methods

The review used an extensive literature search of PubMed, Scopus, and Web of Science databases to identify studies on the neurological effects of LDR published between 1970 and October 2021. The search aimed to find studies that discuss or display the outcome of low-dose radiation exposure to the brain in animal or human models in both in-vitro and in-vivo settings and population-based cohort studies.

Results

The review found that LDR exposure can lead to functional damage, altered neurogenesis, neuroinflammation, and various neurological complications.

  • LDR exposure can cause negative dose-response in cognitive tests and human learning ability.
  • LDR can affect neuronal cells by modulating antioxidant mechanisms, cellular enzyme levels, and other molecules responsible for neuronal survival.
  • LDR exposure can lead to morphological changes, such as retraction of neurite length and reduction in neurite area/soma size.
  • LDR can induce inflammatory responses, activate interferons and insulin-like growth factors, and suppress cell adhesion.
  • LDR can cause cellular stress responses, including morphological dystrophy, abnormal levels of essential enzymes or proteins, and activation of various signaling pathways.

Conclusions

The review concludes that LDR can bring about considerable neurological effects in the exposed individual. Hence, a re-evaluation of the LDR usage levels and frequency of exposure is required. The effects of LDR on the brain are variable and inconclusive, and the response at low doses is unreliable. LDR exposure can cause various changes in the brain, including behavioural changes, morphological changes, and alterations in gene expression, which can lead to neurodegeneration and cognitive impairment. The study also suggests that LDR exposure can have beneficial effects on neurodegenerative diseases, but more research is needed to fully understand its mechanisms and implications. The study also highlights the need for further investigation into the hormetic nature of LDR in humans.

Recommended Citation

Narasimhamurthy RK, Mumbrekar KD, Satish Rao BS. Effects of low dose ionizing radiation on the brain- a functional, cellular, and molecular perspective. Toxicology. 2022 Jan 15;465:153030. doi: 10.1016/j.tox.2021.153030

Publication Date

2022

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