Graphene oxide (GO) and graphene-based nanomaterials have been widely applied in recent years, but their potential health risk and neurotoxic potentials remain poorly understood. In this study, neurotoxic potential of GO and its underlying molecular and cellular mechanism were investigated using the nematode, Caenorhabditis elegans. Deposition of GO in the head region and increased reactive oxygen species (ROS) was observed in C. elegans after exposure to GO. The neurotoxic potential of GO was then investigated, focusing on neurotransmitters contents and neuronal activity using AFD sensory neurons. The contents of all neurotransmitters, such as, tyrosine, tryptophan, dopamine, tyramine, and GABA, decreased significantly by GO exposure. Decreased fluorescence of Pgcy-8:GFP, a marker of AFD sensory neuron, by GO exposure suggested GO could cause neuronal damage on AFD neuron. GO exposure led decreased expression of ttx-1 and ceh-14, genes required for the function of AFD neurons also confirmed possible detrimental effect of GO to AFD neuron. To understand physiological meaning of AFD neuronal damage by GO exposure, locomotive behavior was then investigated in wild-type as well as in loss-of-function mutants of ttx-1 and ceh-14. GO exposure significantly altered locomotor behavior markers, such as, speed, acceleration, stop time, etc., in wild-type C. elegans, which were mostly rescued in AFD neuron mutants. The present study suggested the GO possesses neurotoxic potential, especially on neurotransmitters and AFD neuron in C. elegans. These findings provide useful information to understand the neurotoxic potential of GO and other graphene-based nanomaterials, which will guide their safe application.

中文翻译：

---

氧化石墨烯对秀丽隐杆线虫的神经递质，AFD神经元和机车行为的神经毒性。

近年来，氧化石墨烯（GO）和基于石墨烯的纳米材料得到了广泛应用，但是对它们的潜在健康风险和神经毒性潜力却知之甚少。在这项研究中，使用线虫秀丽隐杆线虫研究了GO的神经毒性潜力及其潜在的分子和细胞机制。暴露于GO后，秀丽隐杆线虫中在头部区域沉积了GO，并增加了活性氧（ROS）。然后研究了GO的神经毒性潜力，重点研究了使用AFD感觉神经元的神经递质含量和神经元活性。接触GO后，所有神经递质（如酪氨酸，色氨酸，多巴胺，酪胺和GABA）的含量均显着降低。AFD感觉神经元标记Pgcy-8：GFP的荧光减弱，通过GO暴露提示GO可能对AFD神经元造成神经元损伤。GO暴露导致ttx-1和ceh-14表达降低，AFD神经元功能所需的基因也证实GO可能对AFD神经元有害。为了了解GO暴露对AFD神经元损害的生理意义，然后研究了野生型以及ttx-1和ceh-14的功能丧失型突变体中的机车行为。在野生型秀丽隐杆线虫中，GO暴露显着改变了运动行为标记，例如速度，加速度，停止时间等，这些标记大多在AFD神经元突变体中得以挽救。本研究提示GO具有潜在的神经毒性，尤其是对秀丽隐杆线虫的神经递质和AFD神经元具有潜在的毒性作用。