Suhexiang Essential Oil Inhalation Produces Antidepressant- And Anxiolytic-like Effects In Stressed Mice

Objective:The present study aimed to investigate the potential antidepressant-and anxiolytic-like effects of SuHeXiang?SHX?essential oil inhalation by using stress-induced depression mice model.Methods:Acute stress-and chronic mild stress?CMS?-induced depression mice model were used in the present study.Forced swimming test?FST?,tail suspension test?TST?and sucrose preference test?SPT?were used to evaluate depressive-like behaviors of mice.Open field test?OFT?and novelty suppressed feeding test?NSF?were used to evaluate anxiety-like behaviors of mice.Experiment 1:Effects of SHX essential oil inhalation on acute stress-induced depressive-and anxiety-like behaviors in miceThirty mice were used and randomly divided into 3 groups?n=10 per group?.One group inhaled 1%Tween80 for 10min as vehicle group?VEH?.The other groups inhaled 10%SHX for 10min?SHX 10 min?or 30 min?SHX30 min?respectively.SHX essential oil inhalation was performed once daily for 12contineuous days.On the ninth day,behavioral tests were conducted sequentially.Experiment 2:Effects of SHX essential oil inhalation on CMS-induced depressive-and anxiety-like behaviors in miceForty mice were randomly divided into na?ve group?n=10?and CMS group?n=30?.Mice in CMS group were exposed to a 28-day CMS treatment.After that,Mice were randomly divided into 3 subgroups and were exposed to1%Tween80 for 10 min?CMS+VEH?,10%SHX for 10 min?CMS+SHX10min?or for 30 min?CMS+SHX30 min?daily for total 12 days.Mice in na?ve group were kept in their homecages without disturbance.After a consecutive8-day inhalation treatment,behavioral tests were carried out sequentially.Results:Result 1:Repeated SHX essential oil inhalation significantly attenuated acute stress-induced depressive and anxiety-like behaviors in miceData from OFT indicated that repeated SHX inhalation for 30 min daily significantly increased the time spent in the central zone(F_2,21=3.805,P<0.05),without effects on the crossing activities(F_2,21=0.633,P>0.05)of mice,compared with that of mice in VEH group.Data from NSF indicated that repeated SHX inhalation significantly decreased the latency to feeding in the NSF(F_2,23=4.108,P<0.05)without effects on total feeding in this test(F_2,23=1.966,P>0.05),compared with that of mice in VEH group.Results from SPT showed that repeated SHX inhalation for 30 min significantly increased sucrose preference in SPT(F_2,22=4.019,P<0.05)with no significant effects on the total water intake(F_2,22=0.657,P>0.05)compared with that of mice in VEH group.Repeated SHX inhalation significantly reduced floating time of mice in FST(F_2,23=11.203,P<0.01).No significant effects on latency to floating(F_2,23=2.709,P>0.05)were found among these three groups.Repeated SHX inhalation for 10 min significantly reduced immobility time(F_2,19=2.951,P<0.05)and prolonged latency to immobility(F_2,19=4.223,P<0.05)of mice in TST,compared with that of mice in VEH group.Result 2:Repeated SHX essential oil inhalation significantly reversed depressive-and anxiety-like behaviors in CMS-treated miceBehavioral results showed that mice exposed to CMS?CMS+VEH?exerted significant depressive-and anxiety-like behaviors,reflected by decreased time spent in central zone(t₁₄=3.609,P<0.01)and crossing activity(t₁₄=3.940,P<0.01)in the OFT,prolonged latency to feeding in the NSF(t₁₃=-2.646,P<0.05),decreased sucrose preference(t₁₄=3.977,P<0.01)in the SPT,increased floating time(t₁₄=-4.988,P<0.01)and shortened latency to floating in the FST(t₁₄=2.368,P<0.05),prolonged immobility time(t₁₄=-3.325,P<0.01)and shortened latency to immobility in the TST(t₁₄=2.260,P<0.05),compared with that of mice in na?ve group.Repeated SHX inhalation significantly reversed the decrease of time in central zone in the OFT(F_2,20=7.674,P<0.01),without effects on crossing in5 min(F_2,20=1.080,P>0.05),compared with that of mice in CMS+VEH group.Repeated SHX inhalation significantly reversed the prolonged latency time to feeding in the NSF(F_2,20=6.716,P<0.01),without effects on total feeding(F_2,20=0.882,P>0.05),compared with that of mice in CMS+VEH group.Repeated SHX inhalation significantly reversed the decreased sucrose preference in the SPT(F_2,20=4.605,P<0.05)with no effects on total intake(F_2,20=1.129,P>0.05),compared with that of mice in CMS+VEH group.Repeated SXH inhalation reversed the increased floating time in the FST(F_2,20=6.387,P<0.05)and repeated SXH inhalation for 10 min reversed the decrease of latency to floating(F_2,20=7.265,P<0.01),compared with that of mice in CMS+VEH group.Repeated SXH inhalation reversed the prolong of immobility time in the TST(F_2,20=3.665,P<0.05)with no effect on latency to immobility(F_2,20=1.820,P>0.05),compared with that of mice in CMS+VEH group.Conclusions:1.SXH inhalation exerts significant antidepressant-and anxiolytic-like activities in mice exposed to acute stress.2.SXH inhalation exerts significant antidepressant-and anxiolytic-like effects in mice exposed to CMS.