Effect of Chaihu Shugan San and its components on expression of ERK1/2 mRNA in the hippocampus of rats with chronic mild unpredicted stress depression.

OBJECTIVE: To explore the antidepressant effect and mechanism of Chaihu Shugan San (CHSGS) composition, a compound traditional Chinese herb medicine and its components. METHODS: Rats were randomly divided into 6 groups: normal control group, model control group, a CHSGS group, a component I group, a component II group and a fluoxetine control group. The depression model was replicated by chronic unpredictable mild stress and single house for 28 d. Behavioral scores of the rats were detected by Open-field test and sucrose solution consumption test, and ERK1/2 mRNA expression in the hippocampus tissue was assayed by real-time fluorescent quantitative PCR. RESULTS: ERK1/2 mRNA expression was down-regulated in the depression model group compared with the normal control group (P<0.01). Compared with the model group, ERK1/2 mRNA expression in the CHSGS group and fluoxetine group was both up-regulated (P<0.05 or P<0.01); and only ERK1 mRNA expression in the component I group was up-regulated (P<0.05). No significant difference existed between the component II group and the model group (P>0.05). CONCLUSION: Isolated-living condition and chronic mild unpredictable stress can down-regulate the expression of ERK1/2 mRNA in the hippocampus tissue. CHSGS may exert an antidepressant effect through increasing the expression of ERK1/2 mRNA in the hippocampus, component I may play an important role in its antidepression effect, while compatibility of the use of component II can enhance the antidepressant efficacy.