【作者】 兰天；

【导师】 赵春燕；

【作者基本信息】 吉林大学 ， 生理学， 2014， 硕士

【摘要】 纳米氧化锌，是纳米家族中性能较为优越的一种材料，粒径在1-100nm范围内，具有纳米材料和传统氧化锌的双重特性，应用前景十分广阔，成为医学生物学研究的热点之一。氧化锌本身是无毒的，但可吸入的氧化锌颗粒是有害的。临床流行病学调查及研究发现，职业暴露氧化锌尘雾中，可以导致类似感冒的急性呼吸道炎症性疾病金属烟雾病(MFF)等[1,2]，表现为肺或呼吸系统炎症反应，对人体健康产生负面影响。这些颗粒物具有纳米级理化特性，不仅本身具有毒性[3]，而且还会对机体造成较大的损伤。氧化锌颗粒通过呼吸进入人体后造成人体机能障碍[4]，对心血管系统产生负面影响[5]。有研究表明，纳米颗粒可以通过毛囊、伸缩或受伤的皮肤渗透[6-8]。因此纳米氧化锌可能具有更强的毒性作用，这就使得纳米氧化锌的健康危害和生态安全性引起了普遍关注。Sharma V等研究表明低浓度的纳米氧化锌，会使表皮细胞产生潜在遗传毒性[9]。例如，在澳大利亚，纳米氧化锌作为防晒霜的成分而广泛使用，每年有超过25万人被诊断为非黑色素瘤皮肤癌，超过8000人为黑色素瘤[10]。刘子宏[11]等人通过气管滴注途径研究纳米氧化锌对小鼠的急性毒性作用，研究发现随纳米氧化锌剂量的增加，肺的炎症反应和增生改变加重。吴诚等[12]通过灌胃途径研究30nm氧化锌颗粒对小鼠的急性毒性，结果显示高剂量的纳米氧化锌可损伤肾脏和肝脏等组织器官，而纳米氧化锌对心血管系统的研究未见报道。本论文以纳米氧化锌为研究对象，观察纳米氧化锌对大鼠心肌生物电活动的影响，我们将采用常规电生理学方法和膜片钳技术观察纳米氧化锌对整体动物心率、离体心肌收缩力和心肌细胞动作电位及Na+、Ca2+离子通道电流的影响，阐明纳米氧化锌对心肌细胞的作用及其电生理学机制，为临床应用提供理论基础。主要实验结果如下：1.在整体水平实验中观察到：纳米氧化锌浓度为10-6M时心率未发生明显变化，而纳米氧化锌浓度为10-5M和10-4M时大鼠心率明显减慢，由550.23±47.26次/min分别降低到451.25±40.13和373.22±38.77次/min。2.在器官水平上观察到：10-5M和10-4M的纳米氧化锌可使心肌收缩幅值明显降低，心肌收缩力减弱，与对照组相比由100%分别降低到94.34±5.12和85.66±6.53%。3.在细胞水平上观察到：纳米氧化锌浓度为10-6M时动作电位未发生明显变化，而纳米氧化锌浓度为10-5M和10-4M时可使动作电位幅值降低，动作电位时程缩短。纳米氧化锌浓度为10-6M时钠、钙峰值电流未发生明显变化，10-5M和10-4M纳米氧化锌INa峰值电流由对照组的-76±6.2pA/pF分别降低到-67±5.6pA/pF(P<0.05)和-61±5.3pA/pF(P<0.01,n=6)。10-5M和10-4M纳米氧化锌ICa峰值电流由对照组的-3.35±0.32pA/pF分别降低到-2.87±0.25pA/pF (P<0.01,n=6)和-2.54±0.21pA/pF (P<0.001,n=6)。综上我们得出如下结论：纳米氧化锌在10-6~10-4M浓度范围内，使心率减慢，心肌收缩减弱，影响心肌细胞的电活动。其机制可能是通过减小大鼠心室肌细胞钠、钙通道电流，使动作电位幅值降低，时程缩短来实现的。更多还原

【Abstract】 Nano zinc oxide is a more superior material in nano-family, particle size in therange1-100nm, with dual properties of nano materials and traditional zinc oxide, theapplication prospect is very broad, and become one of the hotspots of medicalbiology.Zinc oxide itself is not toxic, but zinc oxide particles are harmful. Clinical andepidemiological survey found that occupational exposure to zinc oxide dust cloudsthat can cause flu-like acute respiratory inflammatory disease-metal fume fever(MFF),the performance of the lung or respiratory system inflammatory reaction, havea negative impact on human health. These particles have greater toxicity not only initself, and having nanoscale physicochemical properties, and having a negative impactto human body health. Dysfunctions caused by the body after entering the bodythrough breathing, have a negative impact on the cardiovascular system.Studies have shown that nanoparticles can through the hair follicles, retractableor injured skin penetration. Therefore, nano-zinc oxide may have a stronger toxicity,which makes nano-ZnO health hazards and ecological security caused widespreadconcern. Sharma V and other studies have shown that low concentrations of nano-zincoxide, causes skin cells to produce genotoxic potential of lipid peroxidation andmediated by oxidative stress. For example, in Australia, nano-zinc oxide sunscreeningredients on as widely used, there are over25million people have been diagnosedwith non-melanoma skin cancer each year, and more than8,000human melanoma.Liu Zihong, who studied the acute toxicity of nano-zinc oxide in mice by intratrachealinstillation way, the study found that with increasing doses of nano-zinc oxide, lung inflammation and proliferative changes increased. Cheng Wu studied by intragastricroute30nm zinc oxide particles on the acute toxicity in mice showed that high dosesof nano-zinc oxide can damage the kidneys and liver and other organs, but study ofnano-zinc oxide on the cardiovascular system are not reported.This paper use nano zinc oxide as the research object, observe the effect of nanozinc oxide on cardiac bioelectric activity in rats, we will use the electrophysiology andpatch clamp methods to observe the effect of nano zinc oxide on the whole animalheart rate, myocardial contractility in vitro and isolated cardiomyocytes actionpotential and sodium, calcium ion channels, and clarify the role of nano zinc oxide onmyocardial cells and its electrophysiological mechanisms, and provide a theoreticalbasis for clinical application.The main results are as follows:1. It can be seen in the overall of nano zinc oxide on rat experiments. Comparedwith the control group, in the10-6M concentration range of nano zinc oxide, rat heartrate does not occur, in the10-5M and10-4M concentration range of nano zinc oxide,rat heart rate slowed down, respectively, by550.23±47.26beats/min down to451.25±40.13and373.22±38.77times/min.2. On the organ level observed,10-5M and10-4M of nano-zinc oxide cansignificantly reduce the amplitude of myocardial contractility, decreased myocardialcontractility, compared with the control group, respectively, decreased from100%to94.34±5.12and85.66±6.53%.3. On the cellular level observed: in the10-6M concentration of the actionpotential of nano zinc oxide did not change significantly, in the10-5M and10-4Mconcentration of the nano zinc oxide can decrease action potential amplitude andreduce the action potential schedule shortened. In the10-6M concentration of nanozinc oxide, the peak current of sodium and calcium does not changesignificantly,10-5M and10-4M peak current INaby the nano zinc oxide compared with the control group were reduced to-76±6.2pA/pF-67±5.6pA/pF (P <0.05) and-61±5.3pA/pF (P <0.01, n=6). the peak current of10-5M and10-4M nano-zinc oxideICacompare with control group were reduced to-3.35±0.32pA/pF-2.87±0.25pA/pF (P <0.01, n=6) and-2.54±0.21pA/pF (P <0.001, n=6).In conclusion we draw the following conclusions: Zinc oxide in the10-6-10-4Mconcentration range, the heart rate slows down, weakening myocardial contractility,and affect myocardial cell electrical activity. The mechanism may be by decreasingsodium and calcium channel currents of rat ventricular myocytes, reducing actionpotential amplitude, shortening action potential duration.更多还原