Introduction:

Alpha-mangostin (MAN) possesses a wide variety of pharmacological effects. In this study, we investigated its effect on cholinergic anti-inflammatory pathway (CAP), and tested if CAP regulation was involved in the therapeutic action on acute lung injury (ALI).

Methods:

Male Sprague Dawley rats were pre-treated with MAN (40 mg/kg) for 3 days and ALI was induced with an intraperitoneal injection of lipopolysaccharide (LPS). Certain rats received monolateral vagotomy or sham surgery. The effects on inflammatory reactions and relevant pathways in ALI rats or LPS pre-treated RAW 264.7 cells were investigated by histological, immunohistochemical, immunoblotting, RT-qPCR, and immunofluorescence assays, while levels of proinflammatory cytokines, acetylcholine (Ach) and the enzymatic activity of acetylcholinesterase (AchE) were determined by corresponding quantitative kits.

Results:

Oral administration of MAN reduced the severity of ALI, while vagotomy surgery antagonized this effect. MAN restored the decline in α7 nicotinic acetylcholine receptor (α7nAchR) in the lungs of ALI rats, and promoted the expression of α7nAchR and choline acetyltransferase (CHAT) in RAW 264.7 cells. Although AchE expression was barely affected by MAN at 5 μg/ml, its catalytic activity was reduced by almost 95%. Extracellular rather than intracellular Ach was notably raised shortly after MAN treatment. Furthermore, MAN at 5 μg/ml effectively inhibited LPS-induced increase in phosphorylation and nucleus translocation of p65 subunit, and secretion of TNF-α and IL-1β, which was then offset by methyllycaconitine citrate hydrate.

Conclusion:

MAN activated CAP by increasing peripheral Ach and up-regulating α7nAchR expression, which eventually led to NF-κB inhibition and remission of acute inflammations.

中文翻译：

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胆碱能抗炎通路的激活参与了α-山竹素对脂多糖诱导的大鼠急性肺损伤的治疗作用。

介绍：

α-山竹素 (MAN) 具有多种药理作用。在这项研究中，我们研究了它对胆碱能抗炎通路 (CAP) 的影响，并测试了 CAP 调节是否参与了对急性肺损伤 (ALI) 的治疗作用。

方法：

雄性 Sprague Dawley 大鼠用 MAN (40 mg/kg) 预处理 3 天，并通过腹膜内注射脂多糖 (LPS) 诱导 ALI。某些大鼠接受了单侧迷走神经切断术或假手术。通过组织学、免疫组化、免疫印迹、RT-qPCR 和免疫荧光测定研究了对 ALI 大鼠或 LPS 预处理的 RAW 264.7 细胞的炎症反应和相关途径的影响，同时促炎细胞因子、乙酰胆碱 (Ach) 和酶活性的水平通过相应的定量试剂盒测定乙酰胆碱酯酶（AchE）的含量。

结果：

口服 MAN 可降低 ALI 的严重程度，而迷走神经切断术则拮抗这种作用。MAN恢复了ALI大鼠肺部α7烟碱型乙酰胆碱受体（α7nAchR）的下降，并促进了RAW 264.7细胞中α7nAchR和胆碱乙酰转移酶（CHAT）的表达。尽管 AchE 表达几乎不受 5 μg/ml MAN 的影响，但其催化活性降低了近 95%。MAN 治疗后不久，细胞外而非细胞内 Ach 明显升高。此外，5 μg/ml 的 MAN 有效抑制 LPS 诱导的 p65 亚基磷酸化和核易位的增加，以及 TNF-α 和 IL-1β 的分泌，然后被甲基利乌头碱水合物抵消。

结论：

MAN 通过增加外周 Ach 和上调 α7nAchR 表达来激活 CAP，最终导致 NF-κB 抑制和急性炎症的缓解。