Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
Chemosphere. 2020 Oct;257:127203. doi: 10.1016/j.chemosphere.2020.127203. Epub 2020 May 26.
Information on the occurrence and effects of nanoplastics in ecosystems worldwide currently represent one of the main challenges from the ecotoxicological point of view. This is particularly true for terrestrial environments, in which nanoplastics are released directly by human activities or derive from the fragmentation of larger plastic items incorrectly disposed. Since insects can represent a target for these emerging contaminants in land-based community, the aim of this study was the evaluation of ingestion of 0.5 μm polystyrene nanoplastics and their effects in silkworm (Bombyx mori) larvae, a useful and well-studied insect model. The ingestion of nanoplastics, the possible infiltration in the tissues and organ accumulation were checked by confocal microscopy, while we evaluated the effects due to the administered nanoplastics through a multi-tier approach based on insect development and behaviour assessment, as endpoints at organism level, and the measurements of some biochemical responses associated with the imbalance of the redox status (superoxide dismutase, catalase, glutathione s-transferase, reactive oxygen species evaluation, lipid peroxidation) to investigate the cellular and molecular effects. We observed the presence of microplastics in the intestinal lumen, but also inside the larvae, specifically into the midgut epithelium, the Malpighian tubules and in the haemocytes. The behavioural observations revealed a significant (p < 0.05) increase of erratic movements and chemotaxis defects, potentially reflecting negative indirect effects on B. mori survival and fitness, while neither effect on insect development nor redox status imbalance were measured, with the exception of the significant (p < 0.05) inhibition of superoxide dismutase activity.
目前，关于纳米塑料在全球生态系统中的出现和影响的信息是生态毒理学方面的主要挑战之一。这对于陆地环境来说尤其如此，因为纳米塑料是人类活动直接释放的，或者是由于不正确处理的较大塑料物品的碎片而产生的。由于昆虫可能是陆地群落中这些新兴污染物的目标，因此本研究的目的是评估 0.5μm 聚苯乙烯纳米塑料的摄入及其对家蚕（Bombyx mori）幼虫的影响，家蚕是一种有用且研究充分的昆虫模型。通过共聚焦显微镜检查纳米塑料的摄入、可能的组织渗透和器官积累，同时我们通过基于昆虫发育和行为评估的多层次方法评估由于给予的纳米塑料而产生的影响，作为生物体水平的终点，并测量一些与氧化还原状态失衡相关的生化反应（超氧化物歧化酶、过氧化氢酶、谷胱甘肽 S-转移酶、活性氧评价、脂质过氧化），以研究细胞和分子效应。我们观察到微塑料存在于肠腔中，也存在于幼虫体内，特别是在中肠上皮、马氏管和血细胞中。行为观察显示，不规则运动和趋化性缺陷显著增加（p<0.05），这可能反映了对家蚕生存和适应性的负面影响，而昆虫发育或氧化还原状态失衡均未测量到，除了超氧化物歧化酶活性显著抑制（p<0.05）。
