具有高效抗骨关节炎活性的新型硫酸软骨素多糖的半合成及其构效关系研究

Osteoarthritis attracted much attention for its high incidence and refractory, causing more than half of the elderly to endure pain, inflammation and mobility difficulty that cannot be eradicated. At present, most of the drugs for treating osteoarthritis can only alleviate inflammation and pain. Only a few polysaccharide drugs such as chondroitin sulfate can improve the joint condition, but the clinical effect is unstable due to the change of chemical structure. At the same time, chondroitin sulfate varied into many subtypes that bear different sulfate patterns, and only the easily accessible subtype CS-A has been developed into a drug. Other subtypes have not been studied in depth due to limitations of marine resources, but they have shown potentially superior anti-osteoarthritis activity. Therefore, the study of this class of drugs is the focus and difficulty in the field of anti-osteoarthritis drugs. Based on our previous study that semi-synthetic chondroitin sulfate polysaccharides presented determinate anti-inflammatory and anti-osteoarthritis activities, this project will use CS-A as the starting material to semi-synthesize 14 sulfate patterns of chondroitin sulfate polysaccharides, covering common subtypes and rare marine-derived subtypes and subtypes that have not yet been discovered. Combined application of structure oriented purification, structural analysis and pharmacological screening will be conducted to explore the structure-activity relationship of this series of polysaccharides, and to gain new polysaccharides with high anti-inflammatory and anti-osteoarthritis activity. Then, the mechanism of action on osteoarthritis will be discussed in this item. Our research could provide important scientific theoretical basis for the further synthesis and development of new anti-osteoarthritis polysaccharide drugs.

骨关节炎高发且难治，给半数以上的老年人带来无法根除的疼痛炎症和行动障碍。目前治疗骨关节炎的药物大多只能缓解炎症和疼痛，仅有硫酸软骨素等极少数多糖药物能改善关节病情，但因化学结构多变，其临床效果不稳定。同时，硫酸软骨素有众多亚型，目前只有易得的亚型CS-A成药，其他亚型受到资源限制未能深入开发，但已表现出潜在优越的抗骨关节炎活性。因此，对该类药物的研究是抗骨关节炎药物研究领域的重点与难点。本项目以课题组前期发现的半合成硫酸软骨素多糖具有抗炎与抗骨关节炎活性为基础，以CS-A多糖为原料，半合成14种硫酸亚型的多糖，涵盖常见亚型、罕见亚型以及尚未发现的亚型。联合应用分级纯化和结构分析技术，调控多糖结构，探讨该系列多糖的构效关系，筛选获得有高效抗炎和抗骨关节炎活性的新多糖，并以其作为活性化合物，综合应用药理技术探讨其发挥抗骨关节炎效果的主要作用机制，为新型抗骨关节炎活性多糖的研究开发提供科学依据。

按照项目书内容，本课题制备、分离、纯化了各种可能亚型及不同硫酸化程度的半合成硫酸软骨素多糖，通过巴豆油致小鼠耳肿胀动物模型进行抗炎活性评价，建立了多糖结构与抗炎活性之间构-效关系。为了进一步理解硫酸软骨素多糖结构特点，本课题设计、构建、合成了硫酸软骨素寡糖前体库。通过肿胀抑制率可得，相比于模型组，半合成硫酸软骨素多糖组 (200mg/kg) 在统计学上具有显著性，在该实验模型上具有显著的抗耳肿胀炎症活性，且存在量效关系。进一步体外实验证明，半合成硫酸软骨素多糖可抑制NFκB信号通路，抑制IL-1β、IL-6、iNOS、COX2、MMP3、MMP13等与OA发病密切相关活性分子的产生。木瓜蛋白酶致小鼠OA模型实验结果揭示，半合成硫酸软骨素多糖具有抗骨关节炎活性。初步急毒、亚急毒实验证明，半合成硫酸软骨素多糖具有低毒优点（LD50>5 g/kg），属无毒性的特异性化合物（组织病理、血常规、血生化、尿常规等）。综上所述，从技术层面上看，本项目合成硫酸软骨素多糖可以作为治疗OA潜在治疗药物，进行后续规范化研究。发表SCI论文一篇，申请PCT专利一篇。