Abstract:

Background and purpose: Radiotherapy is one of the main treatment methods for brain tumor patients, but neurotoxicity was observed frequently. Because of the confounding factors in clinical data, it’s hard to summarize the characteristic of neurological changes after brain irradiation. This study used the brain irradiation injury model of rats to test whether brain irradiation change the mood and memory. Methods: Whole brain of SD rats (6-8 weeks old) was exposed to 22 Gy radiation. Open field and elevated plus maze was used to assess the anxiety of rats, passive avoidance was used to assess the mood memory, and novel place recognition was used to assess the spatial memory at 1 month or 10 months after brain irradiation. Results: At 1 month post irradiation, rats moved with less distance and entrance to the central zone of open field with less time, explored the open and closed arms with less time and the exploration of open arms also decreased, entered the darkroom more rapidly during the test phase of passive avoidance, and lose the interest to explore the novel place during novel place recognition. At 10 months post irradiation, rats exhibited similarly with control group during open field and elevated plus maze test, but still entered the darkroom more rapidly during the test phase of passive avoidance, and lose the interest to explore the novel place during novel place recognition. Conclusion: Brain irradiation could decrease the locomotor activity, increase the anxiety mood, reduce the mood and spatial memory; mood dysfunction induced by brain irradiation could restore, but memory impairments would be long-standing.

Key words: Brain irradiation injury, Mood, Memory