Lou Zhaohuan, Zhao Huajun, Lyu Guiyuan
College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China.
Zhejiang Da Xue Xue Bao Yi Xue Ban. 2020 Dec 25;49(6):665-678. doi: 10.3785/j.issn.1008-9292.2020.12.01.
The "lung and large intestine being interior-exteriorly related" is one of the classical theories in traditional Chinese medicine, which indicates a close correlation between the lung and large intestine in physiology and pathology, and plays a pivotal role in guiding the treatment of the lung and bowel diseases. Modern medicine has revealed some connections between the lung and large intestine in tissue origin and mucosal immunity, and preliminarily illuminated the material basis and possible regulatory mechanism of the theory. Recently, this theory has been applied to guide the treatment of refractory lung and intestine diseases such as COVID-19 and ulcerative colitis and has obtained reliable efficacy. Existing research results show that the anatomical homogeneity of lung and large intestine promotes the correlation between lung-bowel mucosal immunity, and mucosal immunity and migration and homing of innate lymphocytes are one of the physiological and pathological mechanisms for lung and large intestine to share. Under the guidance of this theory, Chinese medicines with heat-clearing and detoxifying or tonic effects are commonly used in the treatment of the lung and intestinal diseases by regulating lung-bowel mucosal immunity and they can be candidate drugs to treat lung/intestinal diseases simultaneously. However, the existing studies on immune regulation are mainly focused on the expression levels of sIgA and cytokines, as well as the changes in the number of immune cells such as innate lymphocytes and B lymphocytes. While the following aspects need further investigation: the airway/intestinal mucous hypersecretion, the functional changes of pulmonary and intestinal mucosal barrier immune cells, the dynamic process of lung/intestinal mucosal immune interaction, the intervention effect of local pulmonary/intestinal microecology, the correlation and biological basis between the heat-clearing and detoxifying effect and the tonic effect, and its regulation of pulmonary/intestinal mucosal immunity. In this paper, we try to analyze the internal relationship between lung and intestine related diseases from the point of view of the common mucosal immune system of lung and intestine, and summarize the characteristics and rules of traditional Chinese medicine compound and its active ingredients, which have regulatory effect on lung and intestine mucosal immune system, so as to further explain the theoretical connotation of "lung and large intestine being interior-exteriorly related" and provide reference for the research and development of drugs for related diseases.
“肺与大肠相表里”是中医经典理论之一，表明肺与大肠在生理和病理上密切相关，对指导肺系和肠道疾病的治疗具有关键作用。现代医学揭示了肺与大肠在组织起源和黏膜免疫方面的一些联系，并初步阐明了该理论的物质基础和可能的调控机制。近年来，该理论已被应用于指导治疗如新型冠状病毒肺炎和溃疡性结肠炎等难治性肺肠疾病，并取得了可靠疗效。现有研究结果表明，肺与大肠的解剖学同源性促进了肺肠黏膜免疫的相关性，而黏膜免疫以及固有淋巴细胞的迁移和归巢是肺与大肠共同的生理和病理机制之一。在该理论指导下，具有清热排毒或滋补作用的中药常用于通过调节肺肠黏膜免疫来治疗肺系和肠道疾病，它们可能是同时治疗肺/肠疾病的候选药物。然而，现有的免疫调节研究主要集中在分泌型免疫球蛋白A（sIgA）和细胞因子的表达水平，以及固有淋巴细胞和B淋巴细胞等免疫细胞数量的变化。而以下方面尚需进一步研究：气道/肠道黏液分泌亢进、肺和肠道黏膜屏障免疫细胞的功能变化、肺/肠黏膜免疫相互作用的动态过程、局部肺/肠道微生态的干预作用、清热排毒作用与滋补作用之间的相关性及生物学基础，以及其对肺/肠黏膜免疫的调节作用。本文试图从肺肠共同黏膜免疫系统的角度分析肺肠相关疾病的内在联系，总结对肺肠黏膜免疫系统具有调节作用的中药复方及其活性成分的特点和规律，以进一步阐释“肺与大肠相表里”的理论内涵，为相关疾病药物的研发提供参考。
