Chai Dingyue, Sun Yuzi, Lu Jiamin, Yao Yuhui, Jiang Chunyu, Wu Lihui, Cai Qianqian
Departments of Basic Medicine and Forensic Medicine, Hangzhou Medical College, Hangzhou, People's Republic of China.
Department of Paediatrics, The First Hospital of Jiaxing, Zhejiang, People's Republic of China.
Neuropsychiatr Dis Treat. 2025 Sep 10;21:2035-2052. doi: 10.2147/NDT.S530564. eCollection 2025.
Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent neurodevelopmental disorders in childhood, with a globally increasing incidence. This study aims to investigate alterations in prefrontal cortical lipid metabolism in ADHD model rats and following transcutaneous auricular vagus nerve stimulation (taVNS) intervention, and to elucidate the regulatory effects of the sphingosine kinase inhibitor SKI II on the SPHK-S1P signaling pathway.
Lipidomic analysis was performed to profile the lipid spectrum in prefrontal cortex tissues from Wistar-Kyoto (WKY) control rats, spontaneously hypertensive rat (SHR) ADHD models, sham-operated rats, and taVNS intervention rats. Key sphingolipid metabolic enzymes were assessed by RT-qPCR and Western blot, while sphingosine-1-phosphate (S1P) levels were quantified via ELISA. ADHD model rats received intraperitoneal administration of SPHK inhibitor SKI II (15 mg/kg, 16 days). Behavioral tests evaluated hyperactivity, impulsivity, and anxiety-like phenotypes. Western blot analyzed expression of dopamine synthesis rate-limiting enzyme.
The ADHD model group exhibited significantly elevated ganglioside and lysophospholipid levels. taVNS intervention specifically reduced sphingomyelin content. SPHK1 and SPHK2 mRNA and protein expression were markedly upregulated in ADHD models, concomitant with increased S1P levels. taVNS selectively decreased mRNA expression (without altering protein levels). SKI II administration significantly ameliorated hyperactivity, impulsivity, and anxiety-like behaviors in ADHD models, concurrently restoring dopamine β-hydroxylase expression.
The SPHK-S1P signaling axis is a core pathway driving sphingolipid metabolic dysregulation in the prefrontal cortex in ADHD. Targeted inhibition of this pathway synergistically modulates the expression levels of proteins associated with dopaminergic neurotransmission. The limited regulatory effect of taVNS on sphingolipid metabolism suggests its clinical benefits may stem from multi-pathway synergistic mechanisms.
注意缺陷多动障碍（ADHD）是儿童期最常见的神经发育障碍之一，全球发病率呈上升趋势。本研究旨在探讨ADHD模型大鼠前额叶皮质脂质代谢的变化以及经皮耳迷走神经刺激（taVNS）干预后的情况，并阐明鞘氨醇激酶抑制剂SKI II对SPHK-S1P信号通路的调节作用。
采用脂质组学分析对Wistar-Kyoto（WKY）对照大鼠、自发性高血压大鼠（SHR）ADHD模型、假手术大鼠和taVNS干预大鼠前额叶皮质组织中的脂质谱进行分析。通过RT-qPCR和蛋白质印迹法评估关键鞘脂代谢酶，同时通过酶联免疫吸附测定法对1-磷酸鞘氨醇（S1P）水平进行定量。ADHD模型大鼠腹腔注射鞘氨醇激酶抑制剂SKI II（15 mg/kg，共16天）。行为测试评估多动、冲动和焦虑样表型。蛋白质印迹法分析多巴胺合成限速酶的表达。
ADHD模型组神经节苷脂和溶血磷脂水平显著升高。taVNS干预特异性降低了鞘磷脂含量。ADHD模型中SPHK1和SPHK2的mRNA和蛋白质表达明显上调，同时S1P水平升高。taVNS选择性降低mRNA表达（不改变蛋白质水平）。给予SKI II可显著改善ADHD模型中的多动、冲动和焦虑样行为，同时恢复多巴胺β-羟化酶的表达。
SPHK-S1P信号轴是ADHD前额叶皮质中驱动鞘脂代谢失调的核心通路。对该通路的靶向抑制协同调节与多巴胺能神经传递相关蛋白质的表达水平。taVNS对鞘脂代谢的调节作用有限，提示其临床益处可能源于多途径协同机制。
