Exploring the mechanism of transcutaneous auricular vagus nerve stimulation on improving post-stroke cognitive impairment in MCAO rats using RNA-seq

Our previous findings have shown that taVNS is effective in improving PSCI. However, its specific mechanism and the target genes, biological processes, and signaling pathways it regulates are still unclear and require more in-depth research. We established a cognitive impairment model in MCAO rats and administered taVNS treatment. Cognitive function was assessed using Y-maze and novel object recognition (NOR) experiments. Pathological changes in hippocampal tissue were observed through HE and Nissl staining. RNA-seq was conducted on hippocampal tissue from each group, and differentially expressed genes (DEGs) were performed for GO and KEGG enrichment. Hub genes were identified using the STRING database and betweenness centrality values. taVNS treatment significantly improved cognitive function (Y-maze and NOR) and pathological morphology of hippocampal tissue (HE and Nissl staining) in the PSCI model rats. A total of 341 taVNS targeted DEGs were identified, and they may be implicated in chromosome segregation, mitotic nuclear division, cell cycle, NOD-like receptor signaling pathway, NF-kappa B signaling pathway, and Toll-like receptor signaling pathway, etc. The expression trends of TLR4, Myd88, and NF-κB mRNAs in the Hub genes were significantly inhibited by taVNS.既往研究结果表明，经皮耳迷走神经刺激（transcutaneous auricular vagus nerve stimulation, taVNS）可有效改善卒中后认知障碍（post-stroke cognitive impairment, PSCI）。然而，其具体作用机制以及所调控的靶基因、生物学过程与信号通路仍不明确，有待进一步深入研究。本研究构建了大脑中动脉闭塞（middle cerebral artery occlusion, MCAO）大鼠认知障碍模型，并给予taVNS干预。采用Y迷宫实验与新物体识别（novel object recognition, NOR）实验评估大鼠认知功能，通过苏木精-伊红（hematoxylin-eosin, HE）染色与尼氏染色观察海马组织的病理变化。对各组大鼠的海马组织进行RNA测序（RNA-seq），并对差异表达基因（differentially expressed genes, DEGs）进行基因本体（Gene Ontology, GO）富集分析与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析。利用STRING数据库与介数中心性值筛选核心基因（hub genes）。结果显示，taVNS干预可显著改善卒中后认知障碍模型大鼠的认知功能（Y迷宫与新物体识别实验结果）以及海马组织病理形态（苏木精-伊红染色与尼氏染色结果）。本研究共筛选得到341个taVNS调控的差异表达基因，这些基因可能参与染色体分离、有丝分裂核分裂、细胞周期、NOD样受体信号通路、NF-κB信号通路以及Toll样受体信号通路等生物学过程与信号通路。核心基因中TLR4、Myd88与NF-κB mRNA的表达水平经taVNS干预后显著被抑制。