Hesampour Fatemeh, Tshikudi Diane M, Bernstein Charles N, Ghia Jean-Eric
Immunology, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Canada.
Internal Medicine Section of Gastroenterology, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Canada.
Bioelectron Med. 2024 Dec 9;10(1):29. doi: 10.1186/s42234-024-00162-5.
BACKGROUND: Current inflammatory bowel disease (IBD) treatments often fail to achieve lasting remission and have adverse effects. Vagus nerve stimulation (VNS) offers a promising therapy due to its anti-inflammatory effects. Its invasive nature, however, has led to the development of non-invasive methods like transcutaneous auricular VNS (taVNS). This study assesses taVNS's impact on acute colitis progression, inflammatory, anti-inflammatory, and apoptosis-related markers. METHODS: Male C57BL/6 mice (11-12 weeks) were used for dextran sulfate sodium (DSS)- and dinitrobenzene sulfonic acid (DNBS)-induced colitis studies. The administration of taVNS or no stimulation (anesthesia without stimulation) for 10 min per mouse began one day before colitis induction and continued daily until sacrifice. Ulcerative colitis (UC)-like colitis was induced by administering 5% DSS in drinking water for 5 days, after which the mice were sacrificed. Crohn's disease (CD)-like colitis was induced through a single intrarectal injection of DNBS/ethanol, with the mice sacrificed after 3 days. Disease activity index (DAI), macroscopic evaluations, and histological damage were assessed. Colon, spleen, and blood samples were analyzed via qRT-PCR and ELISA. One-way or two-way ANOVA with Bonferroni and Šídák tests were applied. RESULTS: taVNS improved DAI, macroscopic, and histological scores in DSS colitis mice, but only partially mitigated weight loss and DAI in DNBS colitis mice. In DSS colitis, taVNS locally decreased colonic inflammation by downregulating pro-inflammatory markers (IL-1β, TNF-α, Mip1β, MMP 9, MMP 2, and Nos2) at the mRNA level and upregulating anti-inflammatory TGF-β in non-colitic conditions at both mRNA and protein levels and IL-10 mRNA levels in both non-colitic and colitic conditions. Systemically, taVNS decreased splenic TNF-α in non-colitic mice and increased serum levels of TGF-β in colitic mice and splenic levels in non-colitic and colitic mice. Effects were absent in DNBS-induced colitis. Additionally, taVNS decreased pro-apoptotic markers (Bax, Bak1, and caspase 8) in non-colitic and colitic conditions and increased the pro-survival molecule Bad in non-colitic mice. CONCLUSIONS: This study demonstrates that taVNS has model-dependent local and systemic effects, reducing inflammation and apoptosis in UC-like colitis while offering protective benefits in non-colitic conditions. These findings encourage further research into underlying mechanisms and developing adjunct therapies for UC.
背景:目前的炎症性肠病(IBD)治疗方法常常无法实现持久缓解,且存在不良反应。迷走神经刺激(VNS)因其抗炎作用提供了一种有前景的治疗方法。然而,其侵入性促使了如经皮耳迷走神经刺激(taVNS)等非侵入性方法的发展。本研究评估taVNS对急性结肠炎进展、炎症、抗炎及凋亡相关标志物的影响。 方法:雄性C57BL/6小鼠(11 - 12周龄)用于葡聚糖硫酸钠(DSS)和二硝基苯磺酸(DNBS)诱导的结肠炎研究。在结肠炎诱导前一天开始,每只小鼠给予taVNS或不进行刺激(麻醉但无刺激)10分钟,并每日持续直至处死。通过在饮用水中给予5% DSS 5天诱导溃疡性结肠炎(UC)样结肠炎,之后处死小鼠。通过单次直肠内注射DNBS/乙醇诱导克罗恩病(CD)样结肠炎,3天后处死小鼠。评估疾病活动指数(DAI)、宏观评估和组织学损伤。通过qRT-PCR和ELISA分析结肠、脾脏和血液样本。应用单因素或双因素方差分析以及Bonferroni和Šídák检验。 结果:taVNS改善了DSS结肠炎小鼠的DAI、宏观和组织学评分,但仅部分减轻了DNBS结肠炎小鼠的体重减轻和DAI。在DSS结肠炎中,taVNS在mRNA水平下调促炎标志物(IL-1β、TNF-α、Mip1β、MMP 9、MMP 2和Nos2),从而局部减轻结肠炎症,并在非结肠炎状态下在mRNA和蛋白质水平上调抗炎性TGF-β,在非结肠炎和结肠炎状态下上调IL-10 mRNA水平。在全身水平,taVNS降低了非结肠炎小鼠脾脏中的TNF-α,并增加了结肠炎小鼠血清中TGF-β的水平以及非结肠炎和结肠炎小鼠脾脏中的水平。在DNBS诱导的结肠炎中未观察到这些效应。此外,taVNS在非结肠炎和结肠炎状态下降低了促凋亡标志物(Bax、Bak1和caspase 8),并增加了非结肠炎小鼠中的促生存分子Bad。 结论:本研究表明taVNS具有依赖模型的局部和全身效应,可减轻UC样结肠炎中的炎症和凋亡,同时在非结肠炎状态下提供保护作用。这些发现鼓励进一步研究其潜在机制,并为UC开发辅助治疗方法。
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