马尾松松针提取液对镉毒作用的干预及其机制的研究

Cadmium is a toxin with a long half life and affects multiple organs and systems. Exposure to cadmium in the industrial products or the polluted environment can be toxic and carcinogenic. The use of chelating agent in the prevention and control of cadmium poisoning is associated with considerable side effect, and the therapeutic outcome is not satisfactory. Therefore, the screening of safe intervention factors for cadmium poisoning is a fundamental part of the prevention and control measures. It is reported that the injury caused by oxidative stress is one of the most important mechanisms of cadmium poisoning. Our research shows that the extract of the Pinus massoniana needles exhibits a good anti-oxidative effect, and the extracting method has been applied for the national invention patent. Important is the preliminary results indicate that the extract can reduce the injury caused by oxidative stress in the multiple kinds of cells targeted by cadmium. In the present program, the multiple kinds of cells and rats models of cadmium exposure under different treatment conditions will be built. The toxic effect of cadmium on cells (lung, kidney and bones et al.) and rats and the resulting injury caused by oxidative stress was observed. In the meantime, the intervention and anti-oxidative effects of the extract of Pinus massoniana needles in cadmium poisoning and carcinogenesis were measured in order to verify that the extract of the Pinus massoniana needles could protect the cells and rat organs targeted by cadmium. It was supposed that the intervention effect was related to early response genes, releted response genes and DNA repair genes et al., and the influence of regulation on the oxidative stress. The results will be used as the basis for demonstrating the intervention effect of the extract of Pinus massoniana needles in cadmium poisoning, and the molecular mechanism involved in it will be clarified. Our research sheds light into the mechanism of intervention effect on cadmium toxicity, and the new substances will be found in safe and effective resistance and prevention of cadmium. It also provides new strategies for the prevention and control of cadmium related health risks.

镉是生物半减期很长的多器官、多系统毒物，人类通过工业生产或受污染的环境要素接触到镉而引致机体毒效应和致癌。目前以螯合剂防治镉中毒的效果并不理想且副作用大，因此筛选理想安全的镉中毒干预因素是防治之根本。据文献报道，氧化应激损伤是镉中毒的重要机制之一；我们的研究发现马尾松松针提取液具有良好的抗氧化等功能，并已申请国家发明专利，重要的是初步显示该提取液可降低多种染镉靶细胞的氧化应激损伤。本项目拟创建不同处理条件下多种细胞和动物镉毒性及其干预模型，观察肺、肾、骨等靶细胞和大鼠镉毒效应与氧化应激损伤，探索松针提取液对镉毒性及致癌的干预作用及抗氧化功能，论证该提取液对靶细胞及器官的抗镉和防镉效果，揭示镉中毒干预与早期反应、相关应答和DNA修复等基因表达的关系，以及对氧化应激调控的影响。有望阐明松针提取液对镉毒作用的干预功能及其分子机制，发现安全有效的抗镉及防镉新物质，为人群理想防治镉危害提供新的思路。

镉是生物半减期很长的多器官、多系统毒物，目前以螯合剂防治镉中毒的效果并不理想且副作用大。本项目应用我们的发明专利，开展马尾松松针提取液对镉毒作用的干预及其机制的研究。结果如下：在染镉的人肺16HBE和肾HEK293T细胞中，经松针提取液干预后的细胞活性上升和凋亡率下降；同时MDA和LDH含量逐渐降低，而SOD含量明显升高，均有剂量-反应关系。建立了松针提取液对HEK293T细胞镉毒性的拮抗和预防模型，观察到松针提取液可通过上调抑凋亡基因Bcl-2和氧化应激相关基因SOD、Nrf2的表达及下调促凋亡相关基因Bax和caspase-3的变化来干预镉的细胞毒性；发现松针提取液能明显提高镉处理组的DNA修复基因OGG1和hMSH2的表达量，同时下调早期反应癌基因c-myc的表达，具有时间-反应和浓度-反应关系。整体动物研究表明,各剂量松针提取液可逐渐升高SOD水平和降低MDA水平,各干预组的肝、肾和心OGG1基因表达量比染镉组明显升高而TEF-1δ基因却明显降低，具有剂量-反应关系；经过松针提取液对镉毒作的不同方式的干预，体内血镉和肝、肾镉含量出现有效下降，并与肝、肾、心等器官的氧化应激基因、DNA修复基因和镉相关应答基因密切相关。动物实验进一步表明，染镉组的肾脏和肝脏的金属硫蛋白（MT）明显升高，给予松针提取液干预后的肾和肝的MT下降到对照组的水平，主要靶器官的组织形态学改变也得到一定的修复。以上研究成果表明松针提取液对镉毒性有明显的干预作用，可为揭示和论证松针提取液的抗镉和防镉效果及相关机制提供了科学依据。此外，我们还发现BOK、LTBP2和ASPM基因参与了镉引起的毒性作用和恶性转化过程，这可为松针提取液干预镉毒作用的机制研究提供新的思路。研究成果在国内外期刊上投稿和发表的论文9篇，参加学术会议论文5篇，获得国家发明专利授权1项；培养博士和硕士9名，培养教师和技术人员4名。