小儿中成药“一捻金”中朱砂的潜在神经发育毒性及配伍减毒研究

Cinnabar, mineral containing mercury, has been used in traditional Chinese medicine (TCM) with long history. "China Pharmacopoeia" records herbal preparations containing cinnabar, in which 14 kinds of them are specific for infants and children. Children are more susceptible than adults to the exposure of low-dose mercury. Our previous study found that young mice accumulated more mercury in brain tissue than adults after taking cinnabar; cinnabar may affect the neural development of C. elegans at larval stage. There have increasing concerns about the safety of pediatric medicine comprising cinnabar. The present project plan to study the potential developmental neurotoxicity of cinnabar and detoxification of pediatric medicine “Yinian Jin” as follows:.To investigate the effect of "Yinian Jin" in whole formulae on absorption and accumulation of mercury in cinnabar and changes in species of mercury in weanling rats. To determine the dose-time-effect relationships of the developmental neurotoxicity for oral administration of cinnabar by conducting TK-TD study. To investigate whether whole formulae of "Yinian Jin" reduce the developmental neurotoxicity induced by cinnabar. .Application of the model organism C. elegans during larval stage, to further study whether other TCM compatibility in "Yinian Jin" decrease developmental neurotoxicity of cinnabar; using a higher sensitivity to mercury toxicity model, multidrug resistance protein (MRP-7) knockdown nematode C. elegans, investigate the compatibility detoxification mechanism of "Yinian Jin" mediated by MRP-7 , in order to explore its rationality of the prescription. .This study will provide scientific evidences for safe use of "Yinian Jin" in clinic and to provide a new method for safety evaluation of mineral TCM containing mercury.

朱砂为含汞矿物药，《中国药典》收载含朱砂的儿科专用制剂14种，儿童对于低剂量的汞暴露较成年人有更高的易感性。我们前期研究发现：幼年小鼠服用朱砂，汞更易蓄积在脑组织中；朱砂可能影响幼虫期秀丽线虫的神经发育。含朱砂儿科制剂的安全性研究尤为重要。本项目拟研究小儿中成药“一捻金”中朱砂的潜在神经发育毒性及配伍减毒：用幼年大鼠研究“一捻金”全方对朱砂中汞吸收、蓄积的影响及其汞形态变化，结合毒代动力学和毒性效应（TK-TD）研究，明确“一捻金”中朱砂潜在神经发育毒性的剂量-时间-毒性关系，确认“一捻金”全方对朱砂神经发育毒性的减毒作用。应用秀丽线虫模型，拆方研究“一捻金”对朱砂神经发育毒性的减毒效应；用对汞毒性敏感性更高的多药耐药蛋白（MRP-7）基因敲低线虫，阐明基于MRP-7介导的“一捻金”对朱砂神经发育毒性的配伍减毒机制，为其用药安全提供科学依据，并为含汞矿物药的安全性评价提供新方法。

朱砂为含汞矿物药，含朱砂中成药在儿科中的使用历史悠久，然而其中的朱砂是否影响儿童的神经发育和行为尚不清楚。本项目以常用的含朱砂小儿中成药“一捻金”为研究对象，深入研究“一捻金”中朱砂的潜在神经发育毒性和配伍的其他中药的减毒作用及其机制。在整体啮齿类动物水平研究，发现幼年大鼠较成年大鼠对朱砂中的汞暴露更加敏感，进入体内的汞量更多。与朱砂单方相比，“一捻金”全方中的汞幼年大鼠吸收入血较少，但在其组织内蓄积较多。重复给予相当于临床常用剂量15倍的“一捻金”和相应组方剂量的朱砂对幼年大鼠的肝、肾功能和学习记忆能力均无明显影响。重复给予相当于临床常用剂量15倍的“一捻金”可对幼年大鼠的自主行为有一定抑制作用；重复给予相当于临床常用剂量3倍以上的“一捻金”可引起幼年大鼠的焦虑情绪。.应用模式生物秀丽线虫模型拆方研究“一捻金”对朱砂神经发育毒性的减毒效应，发现4.50 mg/ml剂量的“一捻金”可延缓秀丽线虫幼虫的生长发育、加快头部摆动和排便频率，可能与其组方中的炒牵牛子有关；而组方剂量的朱砂单独给药对秀丽线虫幼虫的生长发育和神经发育并无明显影响。秀丽线虫幼虫暴露于“一捻金”及其拆方后，其摄食、运动和排便行为的改变可能与体内活性氧水平升高以及神经递质系统改变有关。.本研究为“一捻金”临床合理用药提供了新的科学依据，提示“一捻金”常规剂量和相应组方剂量的朱砂对神经发育和和学习记忆能力无明显影响，长期超剂量服用可能影响自主行为和情绪。“一捻金”应按《中国药典》规定的服用量用药，不宜久服，以确保小儿用药的安全性。