Hunan Provincial Key Laboratory of Diagnostic Research in Chinese Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.
Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai' an, Shandong, 271016, China.
J Ethnopharmacol. 2020 Sep 15;259:112979. doi: 10.1016/j.jep.2020.112979. Epub 2020 May 19.
Li-Zhong-Tang (LZT) is a well-known Chinese herbal formulation first described in one of traditional Chinese medicine (TCM) scriptures, Treatise on Febrile Diseases. LZT has been commonly prescribed for the treatment of various gastrointestinal diseases for over 1800 years, and has demonstrated pronounced therapeutic effects on patients with gastric ulcers.
The present study aimed to scientifically evaluate protective effects of LZT on indomethacin (IND)-induced gastric injury in rats and to elucidate whether LZT exerts its gastro-protective effects via enhancing mucosal immunity by regulating TLR-2/MyD88 signaling pathway.
Gastric ulcers were induced in male Sprague-Dawley (SD) rats with a single oral dose of 150 mg/kg IND. Ulcer index (UI) and curative index (CI) were evaluated. Histopathological examinations were performed and microscopic score (MS) was macroscopically calculated. The volume of gastric juice, free acidity, total acidity, and gastric pH was measured. The gastroprotective and inflammatory biomarkers including levels of nitric oxide (NO), tumor necrosis factor-α (TNF-α), prostaglandin E (PGE), and malondialdehyde (MDA) were determined. Expression levels of TLR-2 and MyD88 mRNA were assessed by qRT-PCR. The expression, distribution, and co-localization of TLR-2 and MyD88 protein were determined by Western blot, immunohistochemistry, and immunofluorescence, respectively.
Induction of gastric ulcers in rats resulted in very significantly increased UI and elevated volume and acidity of gastric juice, which were markedly attenuated by LZT treatment. Microscopic examinations of the IND-induced gastric ulcers revealed severe gastric hemorrhagic necrosis, submucosal edema, and destruction of epithelial cells, which were significantly attenuated in LZT-treated rats. Moreover, treatment with LZT remarkably increased gastric mucosal levels of PGE and NO, and lowered highly elevated levels of TNF-α and MDA in gastric ulcerative rats. Mechanistically, LZT inhibited mRNA and protein expression of TLR-2 and MyD88 and enhanced immune function in gastric mucosa. Immunohistochemical analyses and immunofluorescent detection further confirmed a markedly decreased co-localization of TLR-2 and MyD88 protein in the gastric mucosa of LZT-treated rats as compared to that of gastric ulcerative rats.
These findings indicate that LZT alleviates serious gastric mucosal ulcerations induced by IND. Protective effects of LZT on gastric ulcers are believed to be associated with the intensification of the anti-oxidative defense system, mitigation of proinflammatory cytokines, stimulation of the production of cytoprotective mediators, and improvement of the mucosal immunity through TLR-2/MyD88 signaling pathway.
理中汤（LZT）是一种著名的中草药配方，最早在《伤寒论》的一本中医古籍中描述。LZT 已被广泛用于治疗各种胃肠道疾病，已有 1800 多年的历史，对胃溃疡患者具有显著的治疗效果。
本研究旨在科学评估 LZT 对吲哚美辛（IND）诱导的大鼠胃损伤的保护作用，并阐明 LZT 是否通过调节 TLR-2/MyD88 信号通路增强黏膜免疫来发挥其胃保护作用。
雄性 Sprague-Dawley（SD）大鼠给予单剂量 150mg/kgIND 口服诱导胃溃疡。评估溃疡指数（UI）和治疗指数（CI）。进行组织病理学检查，宏观计算微观评分（MS）。测量胃液量、游离酸度、总酸度和胃 pH 值。测定胃保护和炎症生物标志物，包括一氧化氮（NO）、肿瘤坏死因子-α（TNF-α）、前列腺素 E（PGE）和丙二醛（MDA）的水平。通过 qRT-PCR 评估 TLR-2 和 MyD88 mRNA 的表达水平。通过 Western blot、免疫组织化学和免疫荧光分别测定 TLR-2 和 MyD88 蛋白的表达、分布和共定位。
诱导大鼠胃溃疡导致 UI 显著增加，胃液量和酸度显著升高，LZT 治疗明显减弱。IND 诱导的胃溃疡的显微镜检查显示胃出血性坏死、黏膜下水肿和上皮细胞破坏，LZT 治疗的大鼠明显减轻。此外，LZT 治疗可显著增加胃黏膜 PGE 和 NO 的水平，并降低胃溃疡性大鼠中升高的 TNF-α和 MDA 水平。机制上，LZT 抑制 TLR-2 和 MyD88 的 mRNA 和蛋白表达，并增强胃黏膜的免疫功能。免疫组织化学分析和免疫荧光检测进一步证实，与胃溃疡性大鼠相比，LZT 治疗大鼠胃黏膜中 TLR-2 和 MyD88 蛋白的共定位明显减少。
这些发现表明，LZT 可减轻 IND 引起的严重胃黏膜溃疡。LZT 对胃溃疡的保护作用可能与抗氧化防御系统的增强、促炎细胞因子的减轻、细胞保护介质的产生刺激以及 TLR-2/MyD88 信号通路的改善有关。
