Effect of Electroacupuncture at Siguan Acupoints on Expression of BDNF and TrkB Proteins in the Hippocampus of Post-Stroke Depression Rats

Abstract

To study the effect of electroacupuncture at the Siguan acupoints on the expression of hippocampal brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in post-stroke depression (PSD) rats, in order to explore its possible mechanism Fifty specific pathogen-free (SPF)-grade adult male Sprague-Dawley (SD) rats were randomly divided into a blank group, stroke group, PSD group, Siguan acupoint group and fluoxetine group according to the random number method. PSD rats were modeled with middle cerebral artery occlusion combined with chronic unpredictable mild stress. After successful modeling, electroacupuncture was applied to Siguan acupoints for a total of 21 days at 30 min/session/day. The rats in the fluoxetine group were fed intragastrically according to body weight, once a day, for a total of 21 days. The rats in each group were bound and intragastrically administered distilled water every day. The depressive behavior of rats was measured according to the horizontal and vertical scores of the open field test and the sucrose water consumption, and the changes in the number of BDNF- and TrkB-positive cells in the hippocampus of rats were observed by immunohistochemistry. After modeling, the behavioral indicators and the numbers of BDNF- and TrkB-positive cells in each model group were significantly lower than those in the blank group (P < 0.01). After treatment, the behavioral indicators and the numbers of BDNF- and TrkB-positive cells in the Siguan acupoint group and fluoxetine group were significantly higher than that in the PSD group (P < 0.01). During the treatment, the horizontal and vertical scores of the Siguan acupoint group were significantly increased on the seventh day of treatment, and the difference was statistically significant when compared with the PSD group (P < 0.05). The sucrose water consumption was significantly increased on the 14th day of treatment, and the difference was significant when compared with the PSD group (P < 0.05), both of which were earlier than that in the fluoxetine group. During the treatment, there was no significant difference between the two groups (P > 0.05). Electroacupuncture at Siguan acupoints has the same antidepressant effect as fluoxetine, and is more effective than fluoxetine in relieving depression in PSD rats. Its mechanism may be related to the activation of the expression of BDNF and its receptor TrkB.

Keywords: Brain-derived neurotrophic factor; Hippocampus; Post-stroke depression; Siguan acupoints; Tyrosine receptor kinase B.