Saeed El-Ashram ,Dalia Abdel Moneim Kheirallah ,Lamia Moustafa El-Samad,Noura A. Toto
The extensive use of nanomaterials generates toxic effects on non-target species and the ecosystem. Although gold nanoparticles (Au-NPs) are generally expected to be safe, the recent study contains conflicting data regarding their cytotoxicity in the darkling beetles Trachyderma hispida. The study postulated cellular perturbation in the ovarian tissue of the beetles induced by a sublethal dose of Au-NPs (0.01 mg/g). When compared with the controls, a significant inhibition in the activities of the antioxidant enzymes selenium-dependent (GPOX) and selenium-independent (GSTP) glutathione peroxidases (GPx) was observed in the treated beetles. The study proposed microRNAs (miRNA-282 and miRNA-989) as genotoxic markers for the first time, reporting a significant suppression in their transcriptional levels in the treated beetles. Furthermore, TUNEL (Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) and flow cytometry assays (annexin V-Fitc) indicated a significant increase in ovarian cell apoptosis in the treated beetles. Additionally, an ultrastructure examination revealed pathological changes in the ovarian cells of the treated beetles. The resulting anomalies in the present study may interrupt the fecundity of the beetles and lead to the future suppression of beetle populations.
Nanoparticles (NPs) have been involved in the industrial division for over 20 years. The great potential of NPs results from their minute size that facilitates a rapid reaction (quantum size effect or surface-induced effects), which potentially makes them more toxic than traditional-sized particles. NPs (˂ 100 nm) similar in scale to cellular macromolecules may cross the natural mechanical barriers and result in adverse tissue reaction, such as chronic inflammation and disturbance in the metabolism. Therefore, their long-term usage can lead to an imbalance in the ecosystem. The bioaccumulation of NPs is expected to increase the potential risk to the environment and living beings. Their deposition in high quantities will expand the probability of antagonistic unions between living beings and NPs.
Materials & Methods
Ethics Statement: The ethical rules for animal regulations were followed and approved by Faculty of Science, Alexandria University committee in January 2019 (Alex-20-2019).
2.1. Insect identification
Darkling beetles were identified at the Faculty of Agriculture, Alexandria University, Entomology Department, as Trachyderma hispida from the family Tenebrionidae.
2.2. Sampling technique
Beetles were collected from a non-contaminated area in the garden of the Faculty of Science, Elshatby, Alexandria University, Alexandria, Egypt . About 350 specimens were collected and transferred to the lab. They were then placed in containers with native soil and vegetation. The temperature and relative humidity were adjusted to 27 ± 4°C and 80%, respectively, similar to their local habitat.
The specimens were sexed according to the median cleft on the 8th abdominal sternites, which is present in males and absent in females . One hundred and eighty adult females with an average weight of 1.60 ± 0.2 g were divided into nine groups (20 per group). The control group and eight treated groups were injected with saline solution and different doses of Au-NPs, respectively.
Au-NPs have been implicated in several biomedical applications. Despite the promises of engineered nanoparticles (ENPs) in solving medical problems, the potential risks of their use remain undetermined. The increase in the production rate of ENPs subsequently increases the potential release in the environment that may affect the ecosystem’s health. Consequently, understanding their behaviour in biological markers is important. Therefore, terrestrial insects, especially beetles, are acceptable biomarkers that can assess nanotoxicity. Any disturbance in the biological processes in exposed insects may be considered clues for nanotoxicity that might be expected in other living beings.
The authors are thankful to the Zoology Department and Electron microscope unit, Faculty of Science, Alexandria University.
Citation: El-Ashram S, Kheirallah DAM, El-Samad LM, Toto NA (2020) Relative expression of microRNAs, apoptosis, and ultrastructure anomalies induced by gold nanoparticles in Trachyderma hispida (Coleoptera: Tenebrionidae). PLoS ONE 15(11): e0241837. https://doi.org/10.1371/journal.pone.0241837
Editor: Shawky M. Aboelhadid, Beni Suef University, Faculty of Veterinary Medicine, EGYPT
Received: September 21, 2020; Accepted: October 21, 2020; Published: November 6, 2020.
Copyright: © 2020 El-Ashram et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
All relevant data are within the paper and its Supporting information files.
S.E. Start-up Research Grant Program provided by Foshan University, Foshan city, Guangdong province for distinguished researchers, Guangdong Science and Technology Plan Project (Grant No:1244 0600 4560 7389XC) and School of Life Science and Engineering fund (Grant No: KLPREAD201801-02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
The authors have declared that no competing interests exist.