Negative air ion exposure ameliorates depression-like behaviors induced by chronic mild stress in mice

Abstract

The presence of negative air ions (NAI) is suggested to be a good factor in improving psychological status and used in treating depression as an alternative approach. However, the biological explanation for effects of NAI on alleviating depression symptoms has less been explored. In this study, the chronic mild stress (CMS) protocol was used to induce transcriptional depressive-like behaviors in mice, and the effects of NAI exposure on CMS-induced depression-like behaviors were examined. Thirty-day NAI exposure prevented the CMS-induced depression-like behaviors as shown by the restoration of sucrose preference and reduced immobility time in the suspension test. In addition, the elevation of serous corticosterone was present in CMS-treated mice but not existed in those with the NAI exposure. Furthermore, we observed a shifted balance between the cytokines secreted by type 1 T helper (Th1) cells and type 2 T helper (Th2) cells. In conclusion, NAI intervention is able to ameliorate CMS-induced depression-like behaviors in mice, and this effect is associated with the alteration of corticosterone and functional rebalance between Th1 and Th2 cells.