基于水通道蛋白4及cAMP-PKA信号通路探讨藿香正气散干预诺如病毒腹泻的机制

The norovirus diarrhea in children has been paid more and more attention, the common symptoms are diarrhoea, nausea and vomiting, but there is no vaccine and target therapeutic drugs to prevent the disease. Huoxiang Zhengqi decoction is a classic prescription for treating diarrhea, preclinical study shows the definite effect of treating children with acute infectious diarrhea and have better antiemetic effect. But how it regulat he immune system to identify and clear the norovirus has not been reported. Aquaporin-4 (AQP4) is closely related to the regulation of water in the intestinal tract, study have confirmed that cAMP-PKA is involved in the expression of AQPs. So we put forward the scientific hypothesis that "Aquaporins and cAMP-PKA signal pathway is an important pharmacological link of Huoxiang Zhengqi decoction".This study tried to influence by regulating murinenorovirus model of Huoxiang Zhengqi decoction changes on intestinal pathological immune responses and signal pathway related factors. Through the murinenorovirus model to study the effect of Huoxiang Zhengqi decoction on expression of AQP4 、cAMP and PKA to reveal the mechanism of Huoxiang Zhengqi decoction anti norovirus which has great significance to provide the basis for the treatment of norovirus infective diarrhea in children with Chinese Medicine.

诺如病毒腹泻在儿童腹泻中的地位日益受到关注，临床以腹泻、恶心、呕吐多见，但目前尚无疫苗及针对性的抗病毒药物。藿香正气散是治疗腹泻的经典方药，前期临床研究显示其治疗儿童急性感染性腹泻疗效肯定，具有较好的止吐效果。但是该方如何通过调节免疫系统来识别并清除诺如病毒目前国内外尚无报道。水通道蛋白4（AQP4）与肠道水液调节密切相关，近年大量文献证实环腺苷酸-环腺苷酸依赖性蛋白激酶A（cAMP-PKA）参与了AQPs的表达，在调控AQPs过程中具有重要作用。因此本课题提出假说"水通道蛋白及cAMP-PKA信号通路是藿香正气散的重要药理环节”。通过鼠诺如病毒模型探讨藿香正气散对肠道病理变化、肠上皮细胞AQP4表达及cAMP、PKA含量的影响，揭示藿香正气散抗诺如病毒的内在机理，为中医药治疗儿童诺如病毒感染性腹泻提供依据有着重要意义。

诺如病毒(Norovirus, NoV)是全球流行病毒性胃肠炎的主要原因。尽管诺如病毒感染引起的胃肠炎在大多数患者中是自限性的，但在幼儿、老年人和免疫缺陷者中，可能导致病程较长，甚至死亡。目前仍缺乏抗病毒治疗和有效的疫苗接种，对公共卫生造成巨大影响，并造成巨大的经济负担。中医认为泄泻之病，属湿为多。藿香正气散源于宋代《太平惠民和剂局方》，应用至今近千年，具有解暑祛湿、和胃止呕、芳香化浊等功效。本研究通过鼠诺如病毒（MNV）诱导BALB/c小鼠模型，观察感染后小鼠肠组织中水通道蛋白的变化。并予藿香正气散干预，观察其对小鼠炎症因子、AQP4、cAMP及PKA表达的影响。结果发现，与正常组比较，MNV感染组小鼠肠组织中AQP4及AQP8表达下调，AQP4的下调更明显。但AQP4在感染小鼠结肠与小肠组织中的表达无明显差异。藿香正气散干预后，能下调血清及肠组织中IL-6、IL-8、IL-1β和TNF-α，升高肠组织中AQP4、cAMP、PKA表达。结论：藿香正气散对诺如病毒感染小鼠的作用可能与调控cAMP/PKA信号通路，促进AQP4表达有关，为藿香正气散治疗诺如病毒肠炎提供实验依据。