Complex Long-term Effects of Radiation on Adult Mouse Behavior.

Area of Science:

• Radiation biology
• Neuroscience
• Behavioral science

Background:

• Previous studies showed delayed behavioral effects of low-dose radiation in adult mice.
• The impact of higher radiation doses and dose rates on behavior remained largely uncharacterized.

Purpose of the Study:

• To investigate the dose-dependent effects of higher radiation doses and dose rates on a range of behaviors in adult mice.
• To determine if a specific genetic mutation sensitizes mice to radiation-induced behavioral changes.
• To assess the long-term persistence of radiation-induced behavioral alterations.

Main Methods:

• Adult mice (10 weeks old) were exposed to higher radiation doses (0.5, 1, or 2 Gy) at a higher dose rate (0.3 Gy/min).
• Behavioral assessments included locomotion, anxiety, sensorimotor function, cognitive behavior (working memory), and social behavior.
• Mice genotypes included wild-type and Ercc2S737P heterozygous.
• Eye lens integrity was examined 4 months postirradiation.

Main Results:

• Clear dose-dependent effects were observed on locomotor activity, anxiety, body weight, and social behavior, independent of sex or genotype.
• Working memory showed smaller genotype- and dose-dependent radiation effects in males only.
• The strongest effects were evident at 4 months postirradiation, with social behavior effects persisting up to 12 months.
• No radiation-induced alterations were found in the eye lens.
• The Ercc2S737P mutation did not sensitize mice to radiation effects.

Conclusions:

• Higher radiation doses administered at a higher rate induce significant, dose-dependent behavioral changes in adult mice.
• These behavioral effects can be long-lasting, particularly social behavior changes.
• The studied genetic mutation does not confer increased sensitivity to radiation-induced behavioral deficits.
• Radiation-induced behavioral changes are not attributable to ocular damage.