纳米银颗粒对神经元的细胞毒性研究

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(2.5~400 μg·mL^-1)的试样和对照样(100 μg·mL^-1,400 μg·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(100 μg·mL^-1,400 μg·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5~100 μg·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=41.5 μg·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 investigate the cytotoxicity of silver nanoparticles(SNPs) in an in vitro primary culture of cerebral cortex neurons and investigate its mechanism. Methods: SNPs were taken as test samples and silver microparticles(SMPs) as control samples.SNPs and SMPs were cultured with neuron cells at different concentration ranges of 2.5 μg·mL^-1 to 400 μg·mL^-1 and 100 μg·mL^-1 and 400 μg·mL^-1,respectively.After 24 hours of culture,the cell's relative growth rates(RGR) were tested by MTT method and the ultrastructures of cells were evaluated with transmission electronic microscopy(TEM). Results: It demonstrated that the cytotoxicity induced by SNPs were more severe than by SMPs at the same dose(100 μg·mL^-1 and 400 μg·mL^-1).There was a dose-effect relationship between dose and RGR in the range of 5 μg·mL^-1 to 100 μg·mL^-1.And the median inhibitory concentration(IC₅₀) of SNPs in the neuron was 41.5 μg·mL^-1.Observation under the TEM showed SNPs could enter cells,while the SMPs could not. Conclusion: The results suggestes that SNPs entering cells and thus inducing cytotoxicity is the cytotoxicity mechanism of SNPs which is significantly different from that of SMPs.This study demonstrates that once the dimension of silver particles reduces to nanoscale,a new bioeffect will be induced which has potential risk for human health.A cautious attitude should be hold when silver nanoparticles-based medical devices are used in clinical practice.