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目的:研究纳米银颗粒对一种体外原代培养的神经元的细胞毒性作用,并对其细胞毒性机理进行初步推测。方法:试验中以纳米银颗粒为试验样品、微米银颗粒为对照样品,将不同浓度(2.5～400μg·mL-1)的试样和对照样(100μg·mL-1,400μg·mL-1)和神经元细胞共同培养24 h,采用MTT法测定各组细胞的相对增殖率(RGR),并采用TEM观察细胞的超微结构。结果:结果显示,在相同剂量下(100μg·mL-1,400μg·mL-1),纳米银颗粒引起的细胞毒性要显著高于微米银颗粒。当剂量在5～100μg·mL-1的范围内时,纳米银颗粒对神经元的毒性存在有一定的剂量-效应关系,纳米银颗粒对神经元的半数抑制浓度IC50=41.5μg·mL-1。超微结构观察结果显示只有纳米银颗粒能够进入细胞内部,而微米银颗粒不能进入细胞内部。结论:初步推断纳米银颗粒进入细胞内部使其产生细胞毒性是纳米银颗粒细胞毒性的作用机理,这和微米银颗粒具有显著的差异。这也提示我们,一旦银颗粒尺寸降至纳米尺度,将会产生新的生物效应并对人体健康产生危害,具有潜在的风险。因此在使用含有纳米银颗粒的医疗器械时应持谨慎的态度。
OBJECTIVE: To study the cytotoxic effect of nano-silver particles on a kind of primary cultured neurons in vitro, and to preliminarily estimate its cytotoxicity. Methods: Nano-silver particles were used as the test sample and the silver particles as the control sample. Different concentrations (2.5-400μg · mL-1) of the sample and the control sample (100μg · mL-1,400μg · mL-1) The neuronal cells were co-cultured for 24 h. The relative proliferation rate (RGR) of the cells in each group was determined by MTT method. The ultrastructure of the cells was observed by TEM. Results: The results showed that the cytotoxicity of silver nanoparticles was significantly higher than that of silver nanoparticles at the same dose (100μg · mL-1,400μg · mL-1). When the dosage was in the range of 5 ~ 100μg · mL-1, there was a certain dose-effect relationship between the nano-silver particles and the neurons. IC50 of the nano-silver particles to the neurons was 41.5μg · mL-1 . The results of the ultrastructure observation showed that only the nano-silver particles can enter the interior of the cells, while the micro-silver particles can not enter the interior of the cells. CONCLUSION: It is preliminarily concluded that the mechanism of cytotoxicity of nano-silver particles into the cells and the cytotoxicity of the nano-silver particles into the cells has significant difference from that of the micro-silver particles. This also prompts us that once the silver particle size down to nanoscale, will have a new biological effects and human health hazards, with potential risks. Therefore, the use of nano-silver particles containing medical devices should be cautious attitude.