[Electroacupuncture at Baihui and Zusanli improves fear memory extinction in single prolonged stress mice by activating hippocampal astrocytes].

OBJECTIVES

To explore the effect of electroacupuncture (EA) on fear memory extinction in single prolonged stress (SPS) mice and the potential mechanism involving astrocytes.

METHODS

Thirty-six male C57BL/6J mice were randomly divided into the control, SPS model, EA treatment, paroxetine positive drug (PRX), Saline and CNO group. In Saline and CNO group, chemical genetic virus was used to inhibit the hippocampal astrocytes. Except for control group, the other groups were subjected to SPS modeling. After 7 days, the EA, Saline and CNO group were treated with EA at Baihui and Zusanli, while PRX group was given paroxetine solution for 10 days. Fear conditioning test and elevated plus maze test were used to evaluate fear memory extinction and anxiety-like behaviors, and the CNO group was administered CNO 30 minutes before the tests start. Immunofluorescence staining was used to observe the changes in the number and morphology of hippocampal astrocytes, and hippocampal expressions of GFAP and CX43 proteins were detected using Western blotting.

RESULTS

In the mouse models with SPS, EA intervention significantly reduced the freezing time during fear re-exposure for 3-15 min and in the fear extinction phase. EA intervention also significantly increased the extinction coefficient, time spent in the open arms, the mean fluorescence intensity of GFAP, the number of astrocyte branches 50 μm from the soma, and the expression of CX43 proteins in the hippocampus of SPS mice.

CONCLUSIONS

EA at Baihui and Zusanli improves fear memory extinction and anxiety-like behaviors in SPS mice by activating hippocampal astrocytes.