A1 Journal article (refereed)
Irradiation of the head reduces adult hippocampal neurogenesis and impairs spatial memory, but leaves overall health intact in rats (2021)

Lensu, S., Waselius, T., Mäkinen, E., Kettunen, H., Virtanen, A., Tiirola, M., Penttonen, M., Pekkala, S., & Nokia, M. S. (2021). Irradiation of the head reduces adult hippocampal neurogenesis and impairs spatial memory, but leaves overall health intact in rats. European Journal of Neuroscience, 53(6), 1885-1904. https://doi.org/10.1111/ejn.15102

JYU authors or editors

Lensu, Sanna
Waselius, Tomi
Mäkinen, Elina
Kettunen, Heikki
Virtanen, Ari
Tiirola, Marja
Penttonen, Markku
Pekkala, Satu
Nokia, Miriam

Publication details

All authors or editors: Lensu, Sanna; Waselius, Tomi; Mäkinen, Elina; Kettunen, Heikki; Virtanen, Ari; Tiirola, Marja; Penttonen, Markku; Pekkala, Satu; Nokia, Miriam S.

Journal or series: European Journal of Neuroscience

ISSN: 0953-816X

eISSN: 1460-9568

Publication year: 2021

Publication date: 31/12/2020

Volume: 53

Issue number: 6

Pages range: 1885-1904

Publisher: Wiley-Blackwell

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1111/ejn.15102

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/73611

Abstract

Treatment of brain cancer, glioma, can cause cognitive impairment as a side‐effect, possibly because it disrupts the integrity of the hippocampus, a structure vital for normal memory. Radiotherapy is commonly used to treat glioma, but the effects of irradiation on the brain are still poorly understood, and other biological effects have not been extensively studied. Here we exposed healthy adult male rats to small and moderate‐dose irradiation of the head. We found no effect of irradiation on systemic inflammation, weight gain or gut microbiota diversity, although it increased the abundance of Bacteroidaceae family, namely Bacteroides genus in the gut microbiota. Irradiation had no effect on long‐term potentiation in the CA3‐CA1 synapse or endogenous hippocampal electrophysiology, but it did reduce adult hippocampal neurogenesis and impaired short‐term spatial recognition memory. However, no overall cognitive impairment was observed. To summarize, our results suggest that in adult male rats head irradiation does not compromize health or cognition overall even though the number of new, adult‐born hippocampal neurons is decreased. Thus, the sole effects of head irradiation on the body, brain and cognition might be less harmful than previously thought, and the cognitive decline experienced by cancer patients might originate from physiological and mental effects of the disease itself. Therefore, and to increase the translational value of animal studies, the effects of irradiation should be studied together with cancer, in older animals, using varying irradiation protocols and doses.

Keywords: cancer treatments; radiotherapy; physiological effects; neurobiology; electrophysiology; hippocampus; memory (cognition); inflammation; gastrointestinal microbiota; radiobiology; animal disease models