Effects of electroacupuncture on hippocampal ERK/CREB expressions and behaviors in depression model rats

Objective To explore the effects of electroacupuncture (EA) on behaviors and hippocampal extracellular regulated protein kinases (ERK)/cAMP-response element binding protein (CREB) expressions in depression model rats. Methods Forty male SD rats were divided into 4 groups randomly: normal group, model group, EA group and sham EA group (n=10). Chronic unpredictable mild stress (CUMS) and isolation were performed to establish the depression models. EA was applied to Yintang (EX-HN3) and Baihui (GV20) 10 min once a day for two weeks in EA group; sham EA group received placebo treatment. After 4 weeks of intervention, the sucrose intake test, forced swim test and Morris water maze test were used to measure the antidepressant-like effect of EA treatment. The expressions of ERK and CREB in the hippocampus were detected by Western blotting. Results As compared with the model group, the EA group had significantly improved sucrose solution intake ([62.080±11.995]% vs. [74.881±3.308]%) and statistically decreased immobility time([123.668±18.925] s vs. [93.012±15.957] s) in forced swimming (P<0.05). In Morris water maze test, the escape latency to find the target platform became gradually shorter and the frequency of crossing platform significantly increased in EA group (0.900±1.875 vs. 3.200±1.549, P<0.05). The phosphorylated (p)-ERK and p-CREB levels in the EA group were significantly increased as compared with those in the model group (P<0.05). Conclusion EA could improve depression-like behaviors by increasing the levels of p-ERK and p-CREB in the hippocampus. Key words: Depression; Electroacupuncture; Extracellular signal-regulated kinase; cAMP-response element binding protein