Effects of Chaihu Plus Longgu Muli Decoction on Microglial Polarization and Synaptic Plasticity in Post-Stroke Depressed Rats

  OBJECTIVE  To investigate the effects of Chaihu Plus Longgu Muli Decoction on behavior, microglial polarization and synaptic plasticity in post-stroke depression model (PSD) rats.

  METHODS  50 SD rats were divided into sham operation group, model group, and low, medium and high dose groups of Chaihu Plus Longgu Muli Decoction. After middle cerebral artery occlusion (MCAO) operation, chronic unpredictable mild stimulation (CUMS) was performed for 4 weeks, PSD model was established, and Chaihu Plus Longgu Muli Decoction was treated. After treatment, Longa nerve function score was measured, and depression-like manifestations were detected by sucrose preference test and forced swimming test. The expression levels of inflammatory factors interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) in hippocampus were determined by enzyme-linked immunosorbent assay (ELISA). The expression levels of CD16/CD32, CD206 and postsynaptic dense protein-95 (PSD95) in the hippocampus of rats were labeled and quantified by immunofluorescence and Western blot. The synaptic ultrastructure was detected by radio microscopy and the synaptic structure was visualized.

  RESULTS  Compared with the sham operation group, the sucrose preference rate of rats in the model group decreased (P < 0.01), the static time of forced swimming experiment was prolonged (P < 0.01), the expression levels of inflammatory cytokines IL-1β, IL-6 and TNF-α in the hippocampus region and the fluorescence intensity of CD16/CD32 protein in M1 phenotype were increased(P < 0.01), PSD-95, CD206 protein levels were significantly decreased(P < 0.05, P < 0.01), CD16 protein level was increased (P < 0.01). Compared with the model group, the above indexes in the medium and high dose groups of Chaihu Plus Longgu Muli Decoction were significantly improved (P < 0.01).

  CONCLUSION  Chaihu Plus Longgu Muli Decoction can improve the behavioral changes related to post-stroke depression in PSD model rats, and the mechanism may be related to the regulation of microglial polarization and anti-inflammatory, thereby improving synaptic plasticity.