目的 构建了一种针对炎症微环境的结肠靶向-酶敏感纳米给药系统以解决雷公藤红素的递送难题。方法 合成透明质酸-金刚烷甲酸（hyaluronic acid-adamantanecarboxylic acid，HA-AD）聚合物，通过¹H-NMR进行结构确认。采用透析法制备装载雷公藤红素（celastrol，Cel）的纳米粒（Cel/NPs），以包封率为指标，通过单因素考察和Box-Behnken设计-响应面法试验优化改善处方，并测定纳米粒的粒径分布、ζ电位、形态、稳定性、酶敏感性、药物包封率和载药量；采用透析袋法考察纳米粒的体外释放行为；激光共聚焦显微镜和流式细胞仪分析NCM460细胞对药物的摄取情况；建立急性溃疡性结肠炎（ulcerative colitis，UC）小鼠模型，对比研究free Cel和Cel/NPs的体内抗UC作用。结果 最佳制备工艺为Cel 2.04 mg、环糊精27.19 mg、HA-AD 7.96 mg、DMSO 3.0 mL、纯水（reverses osmosis，RO）10 mL、搅拌时间2 h。所得纳米粒为光滑圆整球形，平均粒径为（152.37±1.42）nm，多分散指数（polydispersity index，PDI）为0.262±0.009，ζ电位为（-32.1±0.8）mV，Cel包封率和载药量分别为（94.18±2.36）%、（5.17±0.13）%，递药体系具有较好的储存稳定性和胃肠道稳定性，但在结肠微环境α-淀粉酶的刺激下，可使环糊精迅速解体，从而瓦解Cel/NPs，快速释放Cel；Cel/NPs增加了NCM460细胞对药物的摄取。体内抗UC结果显示Cel/NPs可以显著改善UC，降低小鼠疾病活动指数评分，恢复小鼠结肠组织状态，增加结肠长度，降低脾脏质量，恢复结肠黏膜上皮完整性。结论 所制备Cel/NPs有利于雷公藤红素抗UC靶向递送，显著改善UC，为结肠病变部位药物靶向递送提供新思路。

Objective A colonic targeted and enzyme-sensitive nano-delivery system was constructed based on the inflammatory microenvironment to address the delivery challenges of celastrol (Cel). Methods Firstly, hyaluronic acid-adamantanecarboxylic acid (HA-AD) polymers were synthesized and confirmed by ¹H-NMR. Next, Cel/NPs were prepared by dialysis method and optimized the preparation process with encapsulation efficiency as an index via single factor and Box-Behnken design-response surface method test. Moreover, the particle size distribution, ζ potential, morphology, stability, enzyme sensitivity, drug encapsulation rate and drug loading capacity of the Cel/NPs were determined. The release behavior of Cel/NPs was examined using the dialysis bag method in vitro. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) were used to analyze the intracellular uptake of drug by NCM460 cells. Finally, an acute ulcerative colitis (UC) mouse model was established to comprehensively study anti-UC effect of free Cel and Cel/NPs in vivo. Results The best preparation process was Cel 2.04 mg, cyclodextrin 27.19 mg, HA- AD 7.96 mg, DMSO 3.0 mL, reverses osmosis (RO) water 10 mL, stirring time with 2 h. Cel/NPs showed smooth rounded spherical shape with an average particle size of (152.37 ±1.42) nm, polydispersity index (PDI) of 0.262 ±0.009, ζ potential of (-32.1 ±0.8) mV, respectively. Moreover, the encapsulation rate and drug loading capacity of Cel were (94.18 ±2.36)% and (5.17 ±0.13)%, respectively. On the one hand, Cel/NPs possessed good storage and gastrointestinal stability. On the other hand, the stimulation of α-amylase in the colonic microenvironment could lead to a rapid disintegration of cyclodextrins, which could destroy the Cel/NPs and release Cel rapidly. Cel/NPs increased intracellular uptake of Cel by NCM460 cells. Furthermore, the anti-UC results showed that Cel/NPs significantly ameliorated UC symptom, decreased the disease activity index score in mice, restored the state of mouse colon tissue, increased the length of the colon, decreased the weight of the spleen, and restored the integrity of the epithelium of the colonic mucosa in vivo. Conclusion In summary, the Cel/NPs can facilitate targeted delivery of Cel and improve UC symptom, which provides new strategy for drug-targeted delivery at the site of colonic lesions.

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国家自然科学基金资助项目（82304731）；四川省自然科学基金青年项目（2023NSFSC1784）；成都医学院校基金项目（CYZZD21-02）；2022年国家级大学生创新创业训练计划项目（202213705024）