School of Life Science, East China Normal University, Shanghai, 200241, China.
School of Life Science, East China Normal University, Shanghai, 200241, China.
Chemosphere. 2019 Jan;215:74-81. doi: 10.1016/j.chemosphere.2018.09.176. Epub 2018 Oct 5.
The widespread occurrence and accumulation of plastic waste have been globally recognized as a critical issue. However, there is limited information on the adverse effects of nanoplastics on freshwater invertebrates. In this study, the effects of a polystyrene nanoplastic on physiological changes (e.g., survival, growth, and reproduction) and expression levels of stress defense genes (oxidative stress-mediated and heat shock proteins) in the freshwater flea Daphnia pulex were measured. The results showed that the digestive organs of D. pulex were strongly fluorescent after exposure to the nanoplastic particles, and the 48-h median lethal concentration (LC 50) of the nanoplastic was determined to be 76.69 mg/L. In the 21-day chronic toxicity test, dose- and time-dependent relationships were observed for body length, and the time to first eggs was significantly prolonged in the 0.5 and 1 mg/L groups. The time to clutch was delayed, and total offspring per female and number of clutches were decreased in all the treatment groups. In addition, the offspring per clutch were significantly decreased in the 0.1 mg/L group. As the nanoplastic concentration increased, expression of stress defense genes (SOD, GST, GPx, and CAT) was first induced and then inhibited. The gene expressions of heat shock proteins (HSP70 and HSP90) were induced in all the treatment groups. Our results suggest that nanoplastics can be ingested by the freshwater cladoceran D. pulex and affect its growth and reproduction as well as induce stress defense.
塑料废物的广泛存在和积累已被全球公认为一个关键问题。然而，关于纳米塑料对淡水无脊椎动物的不良影响的信息有限。在这项研究中，研究了聚苯乙烯纳米塑料对淡水蚤（Daphnia pulex）生理变化（如生存、生长和繁殖）和应激防御基因（氧化应激介导和热休克蛋白）表达水平的影响。结果表明，暴露于纳米塑料颗粒后，D. pulex 的消化器官发出强烈荧光，纳米塑料的 48 小时半数致死浓度（LC 50）确定为 76.69 mg/L。在 21 天慢性毒性试验中，体长表现出剂量和时间依赖性关系，0.5 和 1 mg/L 组的首次产卵时间明显延长。卵囊形成时间延迟，所有处理组的总产卵数和产卵次数减少。此外，0.1 mg/L 组的每卵囊产卵数显著减少。随着纳米塑料浓度的增加，应激防御基因（SOD、GST、GPx 和 CAT）的表达先被诱导，然后被抑制。所有处理组的热休克蛋白（HSP70 和 HSP90）基因表达均被诱导。我们的结果表明，纳米塑料可以被淡水枝角类动物 D. pulex 摄入，并影响其生长和繁殖，以及诱导应激防御。
