背景:中枢神经系统对败血症病理生物学的贡献尚未完全了解。在以往的研究中,向小鼠施用内毒素会降低迷走神经抗炎反射的活性。用中枢作用的M1毒蕈碱乙酰胆碱(ACh)受体(M1AChR)治疗减弱了这种内毒素介导的变化。我们假设减少的M1AChR介导的活性有助于盲肠结扎和穿刺(CLP)后的炎症,脓毒症小鼠模型.
方法:在雄性C57Bl/6小鼠中,我们量化了基底前脑胆碱能活性(免疫染色),海马神经元活动,基线时血清细胞因子/趋化因子水平(ELISA)和脾细胞亚型(流式细胞术),在用M1AChR激动剂xanomeline治疗的小鼠中,在CLP之后和CLP之后。
结果:在CLP后48小时,表达胆碱乙酰转移酶(ChAT)的基底前脑细胞的活性是基线时的一半.海马区的活动也较低,其中包含来自表达ChAT的基底前脑神经元的投影。血清TNFα水平,IL-1β,MIP-1α,CLP后IL-6、KC和G-CSF高于基线。CLP后脾巨噬细胞和炎性单核细胞的数量,TNFα+和ILβ+中性粒细胞和ILβ+单核细胞高于基线,而中央树突状细胞(cDCs)的数量,CD4+和CD8+T细胞较低。When,在CLP之后,在基底前脑表达ChAT的神经元中,用xanomeline活性治疗小鼠,并且在海马中明显高于未治疗的动物。CLP后血清TNFα浓度,IL-1β,和MIP-1α,但不是IL-6,KC和G-CSF,在xanomeline治疗的小鼠中显着低于未治疗的小鼠。CLP后脾中性粒细胞数量,巨噬细胞,xanomeline治疗的小鼠的炎性单核细胞和TNFα+中性粒细胞也低于未治疗的动物.IL-1β+中性粒细胞的百分比,IL-1β+单核细胞,cDC,在xanomeline处理和未处理的CLP后小鼠中,CD4+T细胞和CD8+T细胞相似。
结论:我们的发现表明,M1AChR介导的反应调节CLP诱导的某些血清水平的改变,但不是全部,细胞因子/趋化因子和受影响的脾免疫反应表型。
BACKGROUND: The contribution of the central nervous system to sepsis pathobiology is incompletely understood. In previous studies, administration of endotoxin to mice decreased activity of the vagus anti-inflammatory reflex. Treatment with the centrally-acting M1 muscarinic acetylcholine (ACh) receptor (M1AChR) attenuated this endotoxin-mediated change. We hypothesize that decreased M1AChR-mediated activity contributes to inflammation following cecal ligation and puncture (CLP), a mouse model of sepsis.
METHODS: In male C57Bl/6 mice, we quantified basal forebrain cholinergic activity (immunostaining), hippocampal neuronal activity, serum cytokine/chemokine levels (ELISA) and splenic cell subtypes (flow cytometry) at baseline, following CLP and following CLP in mice also treated with the M1AChR agonist xanomeline.
RESULTS: At 48 h. post-CLP, activity in basal forebrain cells expressing choline acetyltransferase (ChAT) was half of that observed at baseline. Lower activity was also noted in the hippocampus, which contains projections from ChAT-expressing basal forebrain neurons. Serum levels of TNFα, IL-1β, MIP-1α, IL-6, KC and G-CSF were higher post-CLP than at baseline. Post-CLP numbers of splenic macrophages and inflammatory monocytes, TNFα+ and ILβ+ neutrophils and ILβ+ monocytes were higher than baseline while numbers of central Dendritic Cells (cDCs), CD4+ and CD8+ T cells were lower. When, following CLP, mice were treated with xanomeline activity in basal forebrain ChAT-expressing neurons and in the hippocampus was significantly higher than in untreated animals. Post-CLP serum concentrations of TNFα, IL-1β, and MIP-1α, but not of IL-6, KC and G-CSF, were significantly lower in xanomeline-treated mice than in untreated mice. Post-CLP numbers of splenic neutrophils, macrophages, inflammatory monocytes and TNFα+ neutrophils also were lower in xanomeline-treated mice than in untreated animals. Percentages of IL-1β+ neutrophils, IL-1β+ monocytes, cDCs, CD4+ T cells and CD8+ T cells were similar in xanomeline-treated and untreated post-CLP mice.
CONCLUSIONS: Our findings indicate that M1AChR-mediated responses modulate CLP-induced alterations in serum levels of some, but not all, cytokines/chemokines and affected splenic immune response phenotypes.