The effect of repetitive transcranial magnetic stimulation on the changes of depressive like behaviors in chronic unpredictable mild stress model rats and its possible mechanism

Abstract

Objective To investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on the depressive like behaviors and expression of brain derived neurotrophic factor (BDNF), IL-1β and NF-κB of hippocampal in chronic unpredictable mild stress (CUMS) rats. Methods Thirty-two adult male rats were randomly divided into four groups (n=8): Control group, Control+ rTMS group, CUMS group and CUMS+ rTMS group. The sucrose preference test, forced swim test and open field test were used to evaluate depressive like behaviors for each groups. In addition, the expression of BDNF, NF-κB and IL-1β in hippo were detected by western blot and ELISA after behavioral test, respectively. Results 1.The effects of rTMS on depressive like behaviors of CUMS rats: in the sucrose preference test, the sucrose preference rate of CUMS rats (0.67±0.06) was significantly lower than Control group (0.91±0.04), which was higher in the CUMS+ rTMS group (0.83±0.08). In the forced swim test, the immobility time of CUMS group ((26.88±11.33)s) was longer than Control group ((15.22±6.75)s) and CUMS+ rTMS group ((18.41±6.95)s). In the open field test, both the total distance traveled and number of central area entry times of CUMS group((849.165±769.01)cm, (7.42±5.68)) were significantly shorter ((6224.81±1403.2)cm) and smaller (22.86±3.72) than Control group, and those of the CUMS+ rTMS were longer ((4105.57±1516.92)cm) and larger (21.25±3.45). All the behavioral results were statistically significant (P 0.05). 2. The effects of rTMS on the hippocampal expressions of BDNF, NF-κB and IL-1β in CUMS rats: compared with Control group, the hippocampal expression of BDNF in CUMS rats was significantly decreased, while the expressions of NF-κB and IL-1β in the hippocampus were significantly increased (P<0.05). Compared with CUMS group, the hippocampa expression of BDNF in the CUMS+ rTMS group was increased, and the expressions of NF-κB and IL-1β in the hippocampus was significantly decreased (P<0.05). There are no expressions of BDNF, NF-κB and IL-1β between Control group and Control+ rTMS group had no differences. Conclusion rTMS increased the expression of BDNF, reduced the production of NF-κB and IL-1β, and alleviated depressive like behaviors in CUMS rats. Key words: Repetitive transcranial magnetic stimulation; BDNF; NF-κB; IL-1β; Rats