载siRNA的新型上转换荧光纳米材料抑制颗粒诱导骨溶解的实验研究

Aseptic loosening induced by periprosthetic osteolysis (PPO) after total joint arthroplasty (TJA) is the key reason for revision surgery, and at present, no drugs could prevent this pathological process efficiently. Recent studies showed us the occurrence of PPO was closely related to the alteration of RANK/RANKL/OPG system with higher ratio of RANKL/OPG, the relative evaluation of RANKL could promote the translocation of NF-κB from cytoplasm to nucleus, which could activate the down-stream osteoclastogenesis pathway, and finally lead to PPO. According to the RNA interfering effect, we used specific siRNA to RANKL in this project to reduce the quantity of RANKL proteins by inhibiting the expression of RANKL gene, which was called “Gene silencing effect”. Moreover, we also carried out sufficient experiments to testify the inhibitive effect of siRNA to RANKL both in vitro and in vivo. Considering the defects of siRNA application—— instability、short effective duration and aimless transmission, we intend to prepare a kind of siRNA loaded controlled-releasing upconversion fluorescence nanoparticles to deal with these shortcomings in this project. The desired nanoparticles could prevent siRNA from degradation and prolong the duration of siRNA inhibitive effect. Moreover, zoledronic acids were combined to the surface of nanoparticles to provide active bone targeting ability, and polyacrylic acid would be combined to the surface to allow the massive release of siRNA under the acid environment caused by bone destruction. All the applied materials aim to promote the inhibitive effect of siRNA to the best. Overall, this project focuses on preparing the desired nanoparticles and evaluating the treatment to wearing debris induced osteolysis by carrying out corresponding experiments both in vivo and in vitro, besides the evaluation of their bone targeting ability and pH-sensitive drug releasing ability. We also engage further experiments to testify the alteration of related molecular mechanism for a broadened understanding to our studies, and we believe this research could offer a novel idea and an effective method for the treatment of PPO after TJA.

人工关节置换术（TJA）后发生假体周围骨溶解（PPO）会导致假体失败，且目前尚无有效的治疗药物。PPO的发生与RANKL/OPG比率的上调密切相关，RANKL可促进NF-κB核内转位并活化下游破骨细胞生成信号通路。本项目根据RNA干扰的原理用RANKL的siRNA对其进行基因沉默，经体内外实验证实了其抑制骨溶解的作用。同时为了解决siRNA易被分解、作用时间短、无靶向性等缺陷，拟制备一种载siRNA的上转换荧光纳米粒，能够保护siRNA不被降解并起缓释作用；在纳米粒表面连接唑来膦酸，使其具有高度骨靶向能力；连接聚丙烯酸，使siRNA能在骨破坏部位的酸性环境下集中释放，进一步提高siRNA的作用效率。本项目从体内、体外实验探讨所制备的上转换荧光纳米释药系统对颗粒诱导骨溶解的治疗效果、靶向特性以及pH反应性,并验证其治疗作用的信号机制，为TJA术后PPO的有效治疗提供新的方法和思路。

人工关节置换术（TJA）后发生假体周围骨溶解（PPO）会导致假体失败，且目前尚无有效的治疗药物。PPO的发生与RANKL/OPG比率的上调密切相关，异常分泌的RANKL蛋白能够作用于破骨前体细胞可促使破骨活化导致骨溶解。本项目设计合成了一种联合了唑来膦酸的纳米载药体系，其具有良好的骨组织靶向的作用。在包载RANKL的siRNA之后能够将siRNA有效地递送至骨组织溶解区域，同时其酸性pH响应性释放特性使siRNA能在骨破坏部位的酸性环境下集中释放，提高siRNA对RANKL基因的沉默效率。项目从体内、体外实验验证所制备的复合纳米载药系统对颗粒诱导骨溶解的治疗效果、靶向特性以及pH反应性，为TJA术后PPO的有效治疗提供新的方法和思路，同时为骨组织相关疾病的纳米载药体系增加了新的应用可能。

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