Possible antidepressant effects and mechanism of electroacupuncture in behaviors and hippocampal synaptic plasticity in a depression rat model

Increasing evidences show that hippocampal synaptic plasticity plays a crucial role in the pathogenesis of depression. The objective of this study was to determine whether electroacupuncture (EA) in the Wistar Kyoto (WKY) rat model of depression would exert antidepressant effects and whether this effect would be associated with changes in hippocampal synaptic plasticity. Male WKY rats were randomly divided into three groups (EA, sham EA, and blank control); Wister rats were used as normal control group. Treatment with EA was performed at Baihui (GV20) and Yintang (EX-HN3) once daily for 3 weeks. Forced swimming test (FST), open field test (OFT), and Morris water maze (MWM) were evaluated after 21-day intervention. Long-term potentiation (LTP) was evoked at Schaffer collateral-CA1 synapses in hippocampal slices in vitro. EA treatment significantly reduced immobility time in FST. MWM test showed a significant downward trend in escape latency time from the second to fifth days of experiment, and a higher frequency of crossing the missing quadrant platform in normal control and EA vs other groups. Impaired LTP was detected in Schaffer collateral-CA1 synapses in blank control and sham EA groups. In the western blot, the expression of GluN2B showed significant increase in EA vs sham EA and blank control groups. EA was able to improve depression-like behaviors and reverse the impairment of LTP, which were likely mediated by GluN2B in the hippocampus.