Sericin has become a promising natural anti-inflammatory protein. However, the biological functions of sericins largely depend on their origins; no study has yet been carried out to comparatively investigate the therapeutic effects of sericins from different sources against inflammatory diseases. Herein, we extracted and purified three kinds of sericins, namely silkworm sericin (SS), tussah sericin (TS), and castor silk sericin (CSS). These sericins showed negligible cytotoxicities against colitis-associated cells (colon epitheliums and activated macrophages). Further investigations displayed that these sericins could remarkably downregulate the secreted amounts of TNF-α, promote the recovery of the damaged colonic epithelial barrier, and eliminate endogenous reactive oxygen species in Raw 264.7 macrophages and Caenorhabditis elegans. In vivo experiments demonstrated that chitosan/alginate hydrogel-encapsulating SS could achieve efficient accumulation of SS in the colitis tissues and thereby play a more effective role in relieving ulcerative colitis (UC) than TS and CSS. Our findings collectively demonstrate that SS can be extracted, formulated, and used as a robust therapeutic agent for the oral treatment of UC.

中文翻译：

---

不同来源的丝胶作为溃疡性结肠炎的自然疗法的比较

丝胶已成为一种有前途的天然抗炎蛋白。然而，丝胶的生物学功能很大程度上取决于它们的来源。尚未进行任何研究来比较不同来源的丝胶对炎症性疾病的治疗效果。在此，我们提取并纯化了三种丝胶，即蚕丝胶（SS）、柞蚕丝胶（TS）和蓖麻丝胶（CSS）。这些丝胶对结肠炎相关细胞（结肠上皮和活化的巨噬细胞）的细胞毒性可忽略不计。进一步研究表明，这些丝胶蛋白可以显着下调 TNF-α 的分泌量，促进受损结肠上皮屏障的恢复，并消除 Raw 264.7 巨噬细胞和秀丽隐杆线虫。体内实验表明，壳聚糖/海藻酸盐水凝胶包封 SS 可以实现 SS 在结肠炎组织中的有效积累，从而在缓解溃疡性结肠炎（UC）方面比 TS 和 CSS 发挥更有效的作用。我们的研究结果共同表明，SS 可以被提取、配制和用作口服治疗 UC 的强大治疗剂。