Dysregulation of miR-124 has been reported to be involved in the pathophysiology of depression. Chaihu-Shugan-San, a traditional Chinese medicine, has antidepressive activity; however, the underlying mechanisms remain unclear. In this study, to generate a rodent model of depression, rats were subjected to a combination of solitary confinement and chronic unpredictable mild stress for 28 days. Rats were intragastrically administered Chaihu-Shugan-San (2.835 mL/kg/d) for 4 weeks, once a day. Real-time reverse-transcription quantitative polymerase chain reaction, miRNA microarray, western blot assay and transmission electron microscopy demonstrated that Chaihu-Shugan-San downregulated miR-124 expression and upregulated the mRNA and protein levels of mitogen-activated protein kinase 14 (MAPK14) and glutamate receptor subunit 3 (Gria3). Chaihu-Shugan-San also promoted synapse formation in the hippocampus. The open field test, sucrose consumption test and forced swimming test were used to assess depression-like behavior. After intragastric administration of Chaihu-Shugan-San, sucrose consumption increased, while the depressive behaviors were substantially reduced. Together, these findings suggest that Chaihu-Shugan-San exerts an antidepressant-like effect by downregulating miR-124 expression and by releasing the inhibition of the MAPK14 and Gria3 signaling pathways.
Keywords: Chaihu-Shugan-San; Gria3; MAPK14; depression; forced swimming test; miR-124; nerve regeneration; neural plasticity; neural regeneration; open-field test; sucrose consumption test; traditional Chinese medicine.