Fractionated Proton Irradiation Does Not Impair Hippocampal-Dependent Short-Term or Spatial Memory in Female Mice

Area of Science:

• Space radiation biology
• Neuroscience
• Cognitive science

Background:

• Space exploration exposes astronauts to high-energy proton radiation (¹H), a significant health concern.
• The hippocampus is crucial for cognitive functions essential for astronaut performance.
• Understanding ¹H exposure effects on the hippocampus is vital for astronaut safety.

Purpose of the Study:

• To investigate the impact of fractionated ¹H irradiation on hippocampal-dependent cognition in female mice.
• To assess potential changes in neurogenesis, gliogenesis, and protein expression post-irradiation.

Main Methods:

• Female CD1 mice were exposed to 0.75 Gy fractionated ¹H (250 MeV) whole-body irradiation.
• Cognitive performance was evaluated 3 months post-irradiation using Y-maze and Morris water maze tests.
• Neurogenic/gliogenic cell counts and proteomic analyses were conducted.

Main Results:

• Irradiated and sham-irradiated mice demonstrated intact spatial and short-term memory in behavioral tests.
• No significant differences were observed in neurogenic or gliogenic cell counts.
• Proteomic analysis showed no significant changes in proteins related to behavior or neural morphology.

Conclusions:

• Fractionated ¹H irradiation at the tested dose did not impair hippocampal-dependent spatial or short-term memory in female mice.
• The hippocampus appears resilient to the tested space radiation exposure levels in this model.
• Further research is warranted to understand long-term effects and potential sex-specific differences.