Aging-Dependent Changes in the Radiation Response of the Adult Rat Brain

Journal Article · Sat Mar 01 04:00:00 EST 2008 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2007.10.054· OSTI ID:21039797

Forbes, M Elizabeth ^[1]; Robbins, Mike E ^[2]; Riddle, David R ^[3]

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1. Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC (United States)
2. Department of Radiation Oncology and Brain Tumor Center of Excellence, Wake Forest University School of Medicine, Winston-Salem, NC (United States)
3. Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, NC (United States)

Purpose: To assess the impact of aging on the radiation response in the adult rat brain. Methods and Materials: Male rats 8, 18, or 28 months of age received a single 10-Gy dose of whole-brain irradiation (WBI). The hippocampal dentate gyrus was analyzed 1 and 10 weeks later for sensitive neurobiologic markers associated with radiation-induced damage: changes in density of proliferating cells, immature neurons, total microglia, and activated microglia. Results: A significant decrease in basal levels of proliferating cells and immature neurons and increased microglial activation occurred with normal aging. The WBI induced a transient increase in proliferation that was greater in older animals. This proliferation response did not increase the number of immature neurons, which decreased after WBI in young rats, but not in old rats. Total microglial numbers decreased after WBI at all ages, but microglial activation increased markedly, particularly in older animals. Conclusions: Age is an important factor to consider when investigating the radiation response of the brain. In contrast to young adults, older rats show no sustained decrease in number of immature neurons after WBI, but have a greater inflammatory response. The latter may have an enhanced role in the development of radiation-induced cognitive dysfunction in older individuals.

• OSTI ID: 21039797
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 70; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
AGING
DAMAGE
HIPPOCAMPUS
INFLAMMATION
IRRADIATION
NERVE CELLS
RADIATION DOSES
RATS