Kumari Mamta, Mukherjee A, Chandrasekaran N
Nanobio-Medicine Group, School of Bio Sciences & Technology, VIT University, Vellore 632014, India.
Sci Total Environ. 2009 Sep 15;407(19):5243-6. doi: 10.1016/j.scitotenv.2009.06.024. Epub 2009 Jul 17.
Potential health and environmental effects of nanoparticles need to be thoroughly assessed before their widespread commercialization. Though there are few studies on cytotoxicity of nanoparticles on mammalian and human cell lines, there are hardly any reports on genotoxic and cytotoxic behavior of nanoparticles in plant cells. This study aims to investigate cytotoxic and genotoxic impacts of silver nanoparticles using root tip cells of Allium cepa as an indicator organism. A.cepa root tip cells were treated with four different concentrations (25, 20, 75, and 100 ppm) of engineered silver nanoparticles (below 100 nm size) dispersion, to study endpoints like mitotic index, distribution of cells in mitotic phases, different types of chromosomal aberrations, disturbed metaphase, sticky chromosome, cell wall disintegration, and breaks. For each concentration five sets of microscopic observations were carried out. No chromosomal aberration was observed in the control (untreated onion root tips) and the mitotic index (MI) value was 60.3%. With increasing concentration of the nanoparticles decrease in the mitotic index was noticed (60.30% to 27.62%). The different cytological effects including the chromosomal aberrations were studied in detail for the treated cells as well as control. We infer from this study that silver nanoparticles could penetrate plant system and may impair stages of cell division causing chromatin bridge, stickiness, disturbed metaphase, multiple chromosomal breaks and cell disintegration. The findings also suggest that plants as an important component of the ecosystems need to be included when evaluating the overall toxicological impact of the nanoparticles in the environment.
在纳米颗粒广泛商业化之前，需要对其潜在的健康和环境影响进行全面评估。尽管关于纳米颗粒对哺乳动物和人类细胞系细胞毒性的研究较少，但几乎没有关于纳米颗粒在植物细胞中的遗传毒性和细胞毒性行为的报道。本研究旨在以洋葱根尖细胞作为指示生物，研究银纳米颗粒的细胞毒性和遗传毒性影响。用四种不同浓度（25、20、75和100 ppm）的工程银纳米颗粒（尺寸小于100 nm）分散液处理洋葱根尖细胞，以研究有丝分裂指数、细胞在有丝分裂阶段的分布、不同类型的染色体畸变、中期紊乱、染色体粘连、细胞壁解体和断裂等终点指标。对每种浓度进行五组显微镜观察。在对照（未处理的洋葱根尖）中未观察到染色体畸变，有丝分裂指数（MI）值为60.3%。随着纳米颗粒浓度的增加，有丝分裂指数降低（从60.30%降至27.62%）。对处理过的细胞和对照细胞详细研究了包括染色体畸变在内的不同细胞学效应。我们从这项研究中推断，银纳米颗粒可以穿透植物系统，并可能损害细胞分裂阶段，导致染色质桥、粘连、中期紊乱、多条染色体断裂和细胞解体。研究结果还表明，在评估纳米颗粒对环境的整体毒理学影响时，需要将植物作为生态系统的重要组成部分纳入考虑。
