Faculty Mentor(s)

Dr. Phillip D. Rivera, Biology

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A major component of NASA’s 2018 strategic plan was to send astronauts to and beyond our lunar orbit within the next couple of decades. A risk to mission success is an astronauts’ exposure to galactic cosmic radiation (GCR), a mixture of chronic low dose, high energy, high charge ion particles (HZE). Previous high energy radiation proton studies show lasting inflammation in the eye in humans treated for uveal melanomas. In mice, HZE particles also showed deficits in cardiac physiology, brain electrophysiology, and memory. Of particular interest to long term mission success are low dose, low energy protons due to their high abundance in the space environment. Given the detrimental physiological and cognitive impact on humans and rodents after high energy proton studies and a lack of low energy proton studies on skin and inflammation, knowledge of how inflammation might respond to chronic low dose, low energy proton radiation is warranted. In our experiment, mice were put into a 50mL conical tube; half were irradiated using the Hope College Pelletron accelerator at a low dose (~2 mGy/wk) of protons. After 10 weeks, half the irradiated mice and half the non irradiated mice were euthanized for molecular studies. Levels of inflammatory cytokines like tumor necrosis factor, which are associated with increased depression, bipolar disorder and schizophrenia were assessed. The other half underwent behavioral tests that looked at stress behaviors. Therefore, the proposed study aimed to test the hypothesis that chronic low dose, low energy proton radiation negatively impacts mental health due to lasting systemic inflammation. Future directions are to examine HZE particles (e.g. Fe, Si, and C) at Brookhaven National Laboratories in Long Island, NY, to compare chronic low energy low dose particles and high energy low dose protons which will help future NASA missions to and beyond lunar orbit.


This work funded in part by Michigan Space Grant Consortium, NASA grant #NNX15AJ20H.

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