SuHeXiang Essential Oil Inhalation Produces Antidepressant- and Anxiolytic-Like Effects in Adult Mice

SuHeXiang (SHX) has been used to treat a wide range of diseases, including those related to the central nervous system. However, the effects of SHX on mood disorders are still elusive. This study aimed to investigate the effects of SHX essential oil on stress-induced depression of mice. In an acute stress-induced depression model, mice inhaled vehicle (1% Tween 80) for 10 min or 10% SHX for 10 or 30 min once daily for 12 continuous days. In the chronic mild stress (CMS)-induced depression model, mice were exposed to a 28-d CMS treatment. Tail suspension test (TST), forced swimming test (FST), sucrose preference test (SPT), open field test (OFT), and novelty suppressed feeding (NSF) test were conducted. In addition, serum levels of angiogenin (ANG), thrombopoietin (TPO), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) were evaluated by enzyme-linked immunosorbent assay (ELISA) assays. The results showed that in mice exposed to acute stress, repeated SHX inhalation exerted significant antidepressant and anxiolytic activities, and also reduced the serum levels of ANG, TPO, IL-6, and TNF-alpha. It also significantly reversed the depressive and anxiety-like behaviors, and reduced the serum levels of ANG and TPO in mice exposed to CMS. This is the first report to show that SHX inhalation could produce significant antidepressant and anxiolytic-like effects. These effects might be mediated by SHX ability to modulate the inflammatory response, and reduce dysfunction of vascular genesis and thrombosis. These results support further exploration for developing SHX inhalation as a novel therapeutic strategy for depression and stress-related disorders.