Pearl Powder Exerts Antidepressant Effects by Modulating the GluN2A/BDNF/PSD-95 Signaling Axis

To evaluate the antidepressant-like effect of pearl powder in rats and explore its potential mechanism based on network pharmacology analysis and experimental validation. The chronic multiple mild stress (CMMS) rat model was applied to evaluate the effects of pearl powder on depression-like behaviors in rats through the sucrose preference test, forced swimming test, and tail suspension test. In addition, based on the identification of the major amino acid components of pearl powder, a network pharmacology analysis was performed to identify potential molecular targets of pearl powder. Subsequently, we compared the identified targets of pearl powder with depression-related targets by a Venn diagram and obtained the intersecting key genes. These genes were further used to construct PPI network and KEGG pathway analysis. Finally, Western blotting assay was applied to verify the protein levels of the relevant targets regulated by pearl powder to explore the underlying mechanisms. The behavioral tests showed that different doses of pearl powder (16.7 mg/kg, 83.3 mg/kg, and 166.7 mg/kg, administered once daily for one week by gavage) significantly improved the sucrose preference and alleviated depression-like behaviors in CMMS rats (FST: immobility time decreased by 12.34% ± 2.34%; TST: immobility time decreased by 12.03% ± 7.75%). After pretreatment of pearl powder with hydrochloric acid, the major amino acids in pearl powder were detected by an automatic amino acid analyzer, with top 5 (Gly, Ala, Glu, Asp, and Arg) accounting for more than 80% of the total amount. Network pharmacology analysis revealed that the top 5 active amino acids in pearl powder could regulate several targets such as CASP3, BDNF, MTOR, GluN2B, and MAPK1. The 84 key genes were also obtained after compared with depression-related target genes. In the following GO enrichment and KEGG pathway analysis, the top 10 items in the bubble plot indicated that pearl powder might exert anti-depression effects by regulating neuronal synaptic membranes and signal transmission. The next Western blot analysis verified that pearl powder could upregulate GluN2Aand synaptic-related proteins PSD-95 and BDNF, thereby improving the synaptic structure and function in the hippocampus. This study first clearly demonstrated that pearl powder significantly improved depressive-like behavior in CMMS rats. By combining network pharmacology and confirmatory experiments, it elucidated that the major active amino acids in pearl powder might participate in the repair of synaptic damage by regulating the expression of synaptic-related proteins, ultimately exerting its pharmacological activity against depression.