从IL-33/ST2信号通路研究麻黄黄芩汤治疗过敏性结膜炎的作用机制

Clinically, allergic conjunctivitis(AC) is one of the most common ocular conditions accompanying with allergic rhinitis，asthma. AC is typeⅠ hypersensitive，which is the result of ocular exposure to an antigen that causes cross-linkage of membrane-bound immunoglobulin E (IgE), resulting in mast cell(MC) degranulation. MC degranulation causes the release of preformed mediators such as histamine, as well as newly formed MC mediators such as prostaglandins. Currently, antihistamines, MC stabilizers and anti-inflammatory agents including steroids and nonsteroidal drugs are conventionally used for the treatment of AC. However, antihistamines and MC stabilizers cannot suppress the activation of free neutrophils and eosinophils. Long-term use of glucocorticosteroids can cause serious side effects such as glaucoma, cataract, Cushing's syndrome, osteoporosis and bacterial infections. Anti-inflammatory and steroid medicine often show side effects with long treatment duration. AC has been one of the challenging issues in terms of ophthalmology because of the high incidence of the disease, long duration, easy to break out repeatedly, limited curative effect..IL-33, a member of the IL-1 cytokine family and a ligand to receptor ST2, has great potential to induce a T helper 2-type inflammatory response. IL-33 is proven to be released by epithelial cells during their injury by different environmental stimuli such as airborne allergens, viruses, and air pollutants. IL-33 acting as an endogenous danger signal is termed an alarmin. As such, this cytokine is considered to play a crucial role in an allergic inflammatory disease such as AC. Anti-IL-33 antibody was found to be effective in suppression of symptoms of the mouse model ovalbumin induced allergic rhinitis and asthma..AC is always a comorbid condition of allergic rhinitis and asthma. It was concluded that AC is one symptom of systemically hypersensitivity in eyes, and it should be treated from the whole. According to TCM, we summarized that the Mahuanghuangqin Decoction（MHD） has good curative effect on AC,and has active effect on control of acute symptom of AC by OVA; reduce the level of IgE and IL4 in blood serum of mice; and also has positive impact on change of mast cell and reduction of chemotaxis on eosinophile and neutrophile granulocyte, which restrained late reation. But its detailed mechanism remains unclear. In this proposal, we firstly propose that the effects of stable mast cell and inhbit degranulation have relationgship with IL-33/ST2 pathway. Then we study the signal pathway and acting targets and clarify the mechanism of MHD regulation the signal pathway of IL-33/ST2 using modern molecular biology technology and cytology technology. Meanwhile, if this mechanism is confirmed, it would be a new strategy for the treatment of both allergic conjunctivitis and other allergic diseases such as asthma and allergic rhinitis in traditional Chinese medicine.

过敏性结膜炎（AC）是眼科常见病之一，主要属于肥大细胞和IgE介导的Ⅰ型超敏反应性疾病。临床上多伴随过敏性鼻炎、过敏性哮喘等疾病发生。因其发病率高、病程长、易反复发作、疗效有限，已属眼科难治性疾病之一。研究表明IL-33/ST2在发病过程发挥重要作用，IL-33能加强IgE介导的过敏反应和持续时间，抑制IL-33可以治疗和防止AC复发。在前期研究中，我们在中医理论指导下，从整体出发，总结出麻黄黄芩汤，可以有效的治疗AC，并下调IgE、IL-4表达，但其具体作用通路尚不明确，推测与调控IL-33/ST2信号通路有关。为深入研究其作用机制，本项目拟采用现代分子生物学技术和细胞学技术，研究其信号通路和作用靶点，阐明麻黄黄芩汤对IL-33/ST2信号通路的调控作用及机理，为中医中药治疗过敏性结膜炎和全身其他Ⅰ型变态反应性疾病（如过敏性哮喘、过敏性鼻炎等）开辟新的治疗途径奠定实验基础。

过敏性结膜炎（AC）是眼科常见病之一，主要属于肥大细胞和IgE介导的Ⅰ型超敏反应性疾病。临床上多伴随过敏性鼻炎、过敏性哮喘等疾病发生。因其发病率高、病程长、易反复发作、疗效有限，已属眼科难治性疾病之一。研究表明IL-33/ST2在发病过程发挥重要作用，IL-33能加强IgE介导的过敏反应和持续时间，抑制IL-33可以治疗和防止AC复发。在前期研究中，我们在中医理论指导下，从整体出发，总结出麻黄黄芩汤，可以有效的治疗AC，并下调IgE、IL-4表达，但其具体作用通路尚不明确，推测与调控IL-33/ST2信号通路有关。我们通过观察麻黄黄芩汤治疗前后 AC 小鼠急性期症状和体征的变化，和后期炎症评估，以及对IL-33/ST2信号通路的影响等实验研究试图阐述其作用机制。我们的结果显示：用鸡卵清白蛋白免疫小鼠可以建立稳定的过敏性结膜炎模型，麻黄黄芩汤可以减少小鼠抓挠次数，减轻结膜充血、水肿和分泌物情况；下调泪液中组胺（HIS）、IL-4 和 IgE 表达；减少结膜组织肥大细胞聚集及脱颗粒。 减少结膜组织病嗜酸性粒细胞数量；减少结膜组织匀浆、结膜组织和外周血中 IL-33 和 ST2 的表达（该部分结果正在复审阶段，尚未公开发表）。说明麻黄黄芩汤可以抑制早期肥大细胞脱颗粒及晚期炎症表现，证实了麻黄黄芩汤对过敏性结膜炎的确切治疗作用，同时也论证了“从肺论治过敏性结膜炎”的正确性，这为中医中药治疗过敏性结膜炎和全身其他Ⅰ型变态反应性疾病（如过敏性哮喘、过敏性鼻炎等）开辟新的治疗途径奠定实验基础。