Online ISSN: 1884-4111 Print ISSN: 0033-8303
Radioisotopes 65(12): 493-506 (2016)


強制水泳誘導うつ病マウスに対するラドン吸入による抗うつ効果の検討Study on Antidepressant-Like Effects of Radon Inhalation on Forced Swim Induced Depression in Mice

岡山大学大学院保健学研究科放射線健康支援科学領域Graduate School of Health Sciences, Okayama University ◇ 700–8558 岡山市北区鹿田町2–5–1 ◇ 2–5–1 Shikata-cho, Kita-ku, Okayama-shi, Okayama Pref. 700–8558, Japan

受付日:2016年6月6日Received: June 6, 2016
受理日:2016年8月25日Accepted: August 25, 2016
発行日:2016年12月15日Published: December 15, 2016

本研究ではラドン療法の新規適応症の探索のため,強制水泳(FST)誘導うつ病マウスに対するラドン吸入による抗うつ効果の有無について検討した。その結果,FSTに伴ううつ様行動や脳内ノルアドレナリン・ドーパミンなどのモノアミンの減少に対し,2,000 Bq/m3ラドンの24時間吸入により抑制することが示唆できた。これらの知見などから,ラドン療法の適応症の一つとして抗うつ効果の可能性のあることがわかった。

In this study, we aimed to find out new indications of radon therapy and examined whether radon inhalation induced antidepressant-like effects in mice. First, we investigated the effects of radon inhalation on the forced swim stress-induced model of depression. We evaluated depression-like symptoms before and after forced swim test (FST). All mice were examined the locomotor activity and the responses to novel environments by open field test, and only depression groups performed depression-like behavior by FST. Pre-treated mice inhaled radon at background (BG) level, or at a concentration of 2,000 Bq/m3 for 24 h before FST, and post-treated mice inhaled similar levels of radon after the FST. Forced swim stress induced depression-like behavior, and 2,000 Bq/m3-radon inhalation alleviated depression-like symptoms compared to BG level concentration. Concurrently, Swim stress induced the decrease in norepinephrine and dopamine levels in brain tissue. Furthermore, swim stress-induced depression reduced superoxide dismutase activity in blood plasma and increased lipid peroxide content in brain tissue. Treatment with radon inhalation produced antidepressant-like effects, i.e., enhanced monoamines, including Serotonin, norepinephrine and dopamine levels in brain tissue, as well as depression-like behavior. These findings indicated that radon inhalation prevented and alleviated swim stress-induced depression-like symptoms in mice.

Key words: radon inhalation; forced swim test; open field test; monoamines; antioxidants

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