背景:在传统中草药中,据说大黄可以清除积累,清热,放火。现代药理学表明,大黄提取物以适当的剂量给予实验动物时具有泻药作用。然而,活性成分及其作用机制仍未明确定义。
目的:本研究旨在评价大黄游离蒽醌(RhA)及其单体对大鼠便秘的协同软化作用,探讨其作用机制。
方法:建立水分亏缺型便秘大鼠模型,这些大鼠用RhA及其单体治疗。ELISA,组织病理学,免疫组织化学,采用基于网络药理学和分子对接的qPCR和Westernblotting方法探讨RhA及其单体的可能作用机制。
结果:RHA,芦荟大黄素,rhein,大黄酚显示出大便软化活性,芦荟大黄素和大黄酸的组合对粪便颗粒的软化作用最强。芦荟大黄素,rhein,和大黄酚显著增加血清血管活性肠肽(VIP)的水平,胃动素(MTL),和P物质(SP),上调VIP的表达,环化酶相关蛋白1(CAP1),蛋白激酶A(PKA),囊性纤维化跨膜传导调节因子(CFTR),水通道蛋白3(AQP3),水通道蛋白4(AQP4),和水通道蛋白8(AQP8),降低了上皮钠通道(ENaC)和Na/H交换子3(NHE3)的表达,并降低便秘大鼠结肠组织Na+-K+-ATPase的浓度。RhA治疗模型大鼠结肠液渗透压,芦荟大黄素,rhein,大黄酚增加了。
结论:芦荟大黄素,rhein,大黄酚是RhA提取物的大便软化成分,成分之间存在一定的药物相互作用。RHA上调VIP表达,激活环磷酸腺苷蛋白激酶A(cAMP/PKA)途径,并进一步刺激CFTR表达,同时抑制NHE3和ENaC表达,导致结肠内腔的高渗状态。然后,水的运输可以由渗透梯度驱动,进而导致AQP3、AQP4和AQP8的表达上调。此外,RhA可能通过增加血清VIP改善胃肠动力,SP,和MTL浓度,从而促进粪便排泄。
BACKGROUND: In traditional Chinese herbal medicine, rhubarb is said to remove accumulation with purgation, clearing heat, and discharging fire. Modern pharmacology has shown that rhubarb extract has a purgative effect when given to experimental animals in an appropriate dose. However, the active components and their mechanism of action are still not clearly defined.
OBJECTIVE: The current research aimed to evaluate the synergistic stool-softening effects and explore the action mechanism of rhubarb free anthraquinones (RhA) and their monomers on constipation in rats.
METHODS: A rat model of water deficit-induced constipation was established to induce constipation, and these rats were treated with RhA and its monomers. ELISA, histopathology, immunohistochemistry, qPCR and Western blotting based on network pharmacology and molecular docking were conducted to explore the possible mechanism of action of RhA and its monomers.
RESULTS: RhA, aloe-emodin, rhein, and chrysophanol showed stool-softening activity, and the combination of aloe-emodin and rhein had the strongest softening effect on faecal pellets. Aloe-emodin, rhein, and chrysophanol significantly increased the serum levels of vasoactive intestinal peptide (VIP), motilin (MTL), and substance P (SP), upregulated the expression of VIP, cyclase-associated protein 1 (CAP1), protein kinase A (PKA), cystic fibrosis transmembrane conductance regulator (CFTR), aquaporin 3 (AQP3), aquaporin 4 (AQP4), and aquaporin 8 (AQP8), decreased the expression of epithelial sodium channel (ENaC) and Na+/H+ exchanger 3 (NHE3), and reduced the colonic tissue concentration of Na+-K+-ATPase in the constipated rats. Osmolality of colonic fluid in model rats treated by RhA, aloe-emodin, rhein, and chrysophanol was increased.
CONCLUSIONS: Aloe-emodin, rhein, and chrysophanol were the stool-softening components of the RhA extract, and there were certain drug-interactions between the components. RhA upregulated VIP expression, activated the cyclic adenosine monophosphate protein kinase A (cAMP/PKA) pathway, and further stimulated CFTR expression while inhibiting NHE3 and ENaC expression, resulting in a hypertonic state in the colonic lumen. Water transport could then be driven by an osmotic gradient, which in turn led to the upregulation of AQP3, AQP4, and AQP8 expression. In addition, RhA likely improved gastrointestinal motility by increasing serum VIP, SP, and MTL concentrations, thus promoting faecal excretion.