Study on the relationship between PSD-95 expression and cognitive impairment in the hippocampus of post-stroke depression rats

Objective To make clear the relationship between postsynaptic density protein (PSD)-95 expression and cognitive impairment in post-stroke depression rats and explore the mechanism in the process of cognitive impairment. Methods 50 rats with uniform behavioral scores were randomly divided into 4 groups: normal group, stroke group, depression group, and post-stroke depression group (n≧6). The model of middle cerebral artery occlusion (MCAO) was established by the suture-occluded method, and the post-stroke depression rat model was established by chronic unpredictable mild stress (CUMS) combined with solitary feeding. The learning and memory ability of rats were evaluated by passive avoidance test. Real Time-PCR and immunohistochemistry method were used to detect the PSD-95 mRNA and PSD-95 protein in the hippocampus. Results After modeling successfully (36 days after operation), compared with the normal group, the depression group and the post-stroke depression group had significant changes: weight loss, the decrease of glucose consumption, the drop of open-field horizontal behavior and vertical behavior, the deficiency of passive avoidance test, the reduction of the expression of PSD-95 protein and mRNA (P<0.05). Conclusion The decrease of PSD-95 expression in the hippocampus of post-stroke depression rats may lead to cognitive impairment. Key words: Post-stroke depression; Postsynaptic density protein (PSD)-95; Cognitive impairment