f-MRI and High Throughput mRNA sequencing reveals potenti-al therapeutic targets of Si-Ni-San in a stress-induced depressionmodel

Abstract

Abstract Background: Despite the confirmed good efficacy of Si-Ni-San (SNS) in the treatment of depression, its antidepressant mechanism has remained unclear. Th-is study aimed to systematically explore the potential target brain areas and m-olecular biological basis of SNS in the treatment of depression. Methods: Two experiments were conducted. In experiment 1, 18 male Sprague-Dawley(SD) rats were divided into three groups: a Control (C) group, a Model（M）group and a Stress + SNS (MS) group. The potential target brain regi-ons of SNS were explored using f-MRI. In experiment 2, 32 rats were rando-mly divided into four groups, with the same three groups (C, M and MS) andan additional Stress + Fluoxetine (MF) group. Open field test (OFT), sucrose preference test (SPT), object recognition test (ORT) were performed to test S-NS’s antidepressant effect. High Throughput mRNA Sequencing (RNA-seq) was us-ed to explore the possible gene targets of SNS on the crucial brain region and quantitative real-time PCR (qRT-PCR) was performed to verify the result. High-performance liquid chromatography was utilized to detect the neurotrans-mitters. Finally, correlation analyses between the behavior, genes, and neurotra-nsmitters were conducted to explore the relationship between them. Results: Fifteen brain regions affected by SNS were screened out in experiment 1. In experiment 2, SNS significantly improved sucrose preference in the SPT and B-A in the ORT compared to the M group (P<0.05). Pons was selected from the fifteen brain regions for detailed study. RNA-seqfiltered 49 DEGs that SNS can reverse on the CUMS-depression model. Real-time PCR detected six genes, including Cplx2, Serpinf1, Nrg1, Anxa1, Arrb1 and Psen1. SNS significantly reversed the changes in the genes of Anxa1, Nrg1, and Psen1 caused by CUMS (P<0.05), which aligns with the DEGs result. SNS significantly reversed the NE change in the CUMS model. The correlation analysis discovered 18 noteworthy correlations between the behavior, genes, and neurotransmitters (P<0.05). Conclusions: Pons is an important target brain region for SNS to exert its ant-idepressant effect. SNS may improve the level of pontine NE by regulating the genes of Anxa1, Nrg1, and Psen1, thereby exerting anti-depression and improv-ing cognitive function.