光敏凝胶/微纳米钙磷缓释抗炎、促矿化NGR1的新型盖髓材料构建及作用机制研究

In the pathological states such as deep caries and accidental pulp exposure, pulp capping is needed to inhibit the release of inflammatory factors and oxidative stress to avoid pulp inflammation and necrosis. However, the currently clinically-used pulp-capping materials bear several limitations, such as thin reparative dentin, long repairing time and insufficient anti-inflammatory property. Our previous studies have already shown that Chinese Medicine-derived small molecule-notoginsenoside R1 (NGR1) can significantly antagonize oxidative stress, so as to maintain cell viability and reduce cell damage. At the same time, notoginsenoside R1 can also effectively promote cell mineralization in a dose-dependent manner. However, hitherto, the molecular mechanisms accounting for these phenomena are not clarified. In this project, we will explore the signaling pathway transduction mechanism accounting for the effect of NGR1 in antagonizing inflammation, oxidative stress and inducing dentin formation through cellular and molecular biological techniques, such as gene sequencing, ELISA and so on. In the previous work of our group, we have already successfully fabricated highly biocompatible, photosensitive methylacrylic acid anhydride-modified gelatin with high and fast liquid-solid conversion capacity, as well as micro-nano calcium phosphate that can internally incorporates and controlled releases growth factors. In this project, we wish to construct a photosensitive gel/micro-nano calcium phosphate complex with slowly released NGR1. In direct pulp-capping animal models, we will monitoring the expression changes of key factors for pulpitis and dentin formation, using various histological techniques, such as immunohistochemistry. In this way, we will develop an optimized, novel pulp-capping material with highly effective anti-inflammatory and pro-mineralization properties for eventually realizing its clinical translation.

牙髓在深龋、意外露髓等病理状态下需要盖髓治疗来抑制炎症因子释放和氧化应激反应，避免炎症和坏死。然而，目前临床使用的盖髓材料存在形成修复性牙本质较薄、所需时间长，炎性浸润不易缓解等不足。课题组研究表明：中药单体三七皂苷R1（NGR1）能够显著对抗氧化应激，保持细胞活性，减少细胞损伤，同时NGR1还能够剂量依赖高效促进细胞矿化。然而其发挥作用的分子机制尚不明确。本项目拟通过基因测序、ELISA等细胞、分子生物学技术探究NGR1抗炎、抗氧化应激、促牙本质形成的信号通路转导机制。课题组前期已成功合成具有高生物相容性、可快速液固转换的光敏甲基丙烯酸酐改性明胶以及可内部负载、且局部缓释的微纳米钙磷颗粒。我们拟通过复合光敏凝胶/微纳米钙磷材料来缓释NGR1，在直接盖髓动物模型中，通过免疫染色等方法观察牙髓炎症及牙本质生成的关键因子表达，从而优化出一种高效抗炎、促矿化的新型盖髓材料，以期最终获得临床转化。

牙髓在深龋、意外露髓等病理状态下需要盖髓治疗来抑制炎症因子释放和氧化应激反应，进而防治牙髓炎症和坏死。然而，目前临床使用的盖髓材料存在以下不足：诱导形成的修复性牙本质薄弱、所需时间较长，炎性浸润不易缓解。针对以上问题，构建一种可有效抵抗牙髓炎症反应，高效促进牙本质再生的盖髓材料具有重要意义。课题组研究表明：中药单体三七皂苷R1（NGR1）能够显著对抗牙髓细胞的炎症损伤，保持细胞活性，并且NGR1呈剂量依赖性促进牙髓细胞的矿化。然而其发挥作用的分子机制尚不明确。课题组合成一种具有良好生物活性和物理性能的复合光敏凝胶来装载NGR1，在直接盖髓动物模型中，通过免疫染色、microCT等方法证明该材料能够显著抑制牙髓氧化应激损伤，促进修复性牙本质再生。在体外细胞实验中，进一步验证NGR1能诱导小鼠前成牙本质细胞（mDPC6T）成牙本质向分化，并进一步探究其促成牙本质向分化的分子机理。综上，基于盖髓治疗的临床问题，本项目构建出一种高效抗炎、促矿化的新型盖髓材料，具有良好的临床应用前景。