萝卜硫素缓释微球的制备、体内代谢行为及对癌症防治功效研究

Sulforaphane (SF) has a broad application prospects, because of the wide source of its raw materials and its significant effects on cancer prevention and therapy. However, there is lack of a clear relationship between the metabolic and efficacy of SF in vivo in current studies, and the results of SF multi-frequency intake to keep its plasma concentration and activate the cancer defense system have put forward new requirements for SF delivery optimization. In this project, CS-ALG-SF sustained-release microspheres are prepared by using chitosan (CS) and sodium alginate (ALG) as carriers. The metabolic behavior and bioavailability of CS-ALG-SF are studied. On the basis of screening and optimizing the factors affecting loading and encapsulation efficiency, different sustained-release rate microspheres are obtained by controlling the film composition and the layer number. The effects of sustained release rate and supply of microspheres on the absorption, tissue distribution and metabolic dynamics of SF are studied, and the effects of sustained-release of SF on its metabolism are also clearly identified. Based on normal rats and rats chemically induced by carcinogen, the effect of SF microspheres on cancer prevention and therapy are investigated. And then, the regulation mechanism of SF sustained release metabolism on cancer defense system are explored and their intrinsic relationship are elucidated. It is of great significance to implement this project, with the aim to optimize the SF delivery in vivo, fully understand the relationship between SF metabolism and its efficacy in vivo and finally to enhance the role of SF on cancer prevention and therapy.

萝卜硫素（SF）因原料来源广泛、对癌症防治效果显著而具有广阔应用前景。但目前研究中SF供给形式多样而导致其体内代谢与功效关系不明确，同时SF多频次摄入有助于维持其血浆浓度进而激活癌症防御体系的研究结果对SF递送方式优化提出了新要求。本项目以壳聚糖（CS）、海藻酸钠（ALG）为载体，制备CS-ALG-SF缓释微球，研究其体内代谢行为及生物学功效。通过筛选及优化影响微球载药量、包封率因素及对膜层构成与层数控制，获得不同缓释速率微球；研究微球缓释速率及供给量对SF体内吸收、组织分布、代谢动力学影响作用，明确缓释效应影响下SF代谢规律；以正常及致癌物诱导肝癌大鼠为模型，研究SF微球对癌症的防治功效并探索SF缓释代谢对癌症防御体系的调控机制，阐明SF缓释代谢与癌症防治功效的内在关系。本项目实施对优化SF体内递送，深入理解SF体内代谢与功效关系，提升SF对癌症的防治作用具有重要意义。

萝卜硫素（SF）因原料来源广泛、对癌症防治效果显著而具有广阔应用前景。但目前研究中SF供给形式多样而导致其体内代谢与功效关系不明确，同时SF多频次摄入有助于维持其血浆浓度进而激活癌症防御体系的研究结果对SF递送方式优化提出了新要求。针对SF在纯水溶性体系中包埋率低问题，本项目构建了以醇溶性Zein为核心的纳米粒子载体，并以此为核心构建多层缓释微球的方法。基于静电喷雾和反溶剂法分别制备了Zein纳米粒子，其中反溶剂法制备纳米粒子本身具有较好的SF缓释作用，以其为核心制备的微球粒径小、缓释效果好，同时大幅提高了SF的贮藏稳定性。包封对大鼠体内 SF 代谢及组织分布规律影响结果表明，SF经包埋后血浆半衰期和达峰时间都显著延长，血药浓度-时间曲线下面积显著增加，且使得各脏器中SF浓度显著高于游离SF摄入，表明包封可明显提高SF生物利用度，具有良好的促进吸收作用。DEN诱导小鼠并未出现肝癌，但模型组与干预组肝损伤的差异仍表明SF对DEN诱导的肝损伤有明显预防作用。SF干预处理可显著抑制肝功能损伤标志酶ALT、AST、AKP、r-GT活性及总胆红素的增加，显著提高SOD、CAT、GPX、GR抗氧化酶活性及GSH的含量，激活Nrf-2/Keap1信号通路Nrf2及下游NQO1、HO-1的表达并增强对细胞凋亡的抵抗性。本项目的创新性发现是首次证实了SF包封缓释可增强其生物学功效，即较游离SF，SF包封缓释对DEN诱导的肝损伤有更强的预防作用。除此之外，SF干预作用表现出明显的剂量依赖性及作用的持续性，即100 μmol/kg/d处理效果显著优于低剂量（50 μmol/kg）重复处理（2次/d）以及高剂量（200 μmol/kg）隔天处理效果。. 本项目证实SF包封不仅可以提高其稳定性，还可以提高其疾病预防效果，这一方面为开发稳态化SF产品以商业化应用提供了解决方案，另一方面为SF功能性的提升提供了创新思路和重要科学依据。