Effects of copper oxide nanoparticles on reproductive system of zebrafish

A Pretty Kettle of Fish: A Review on the Current Challenges in Mediterranean Teleost Reproduction

The Mediterranean region is facing several environmental changes and pollution issues. Teleosts are particularly sensitive to these challenges due to their intricate reproductive biology and reliance on specific environmental cues for successful reproduction. Wild populations struggle with the triad of climate change, environmental contamination, and overfishing, which can deeply affect reproductive success and population dynamics. In farmed species, abiotic factors affecting reproduction are easier to control, whereas finding alternatives to conventional diets for farmed teleosts is crucial for enhancing broodstock health, reproductive success, and the sustainability of the aquaculture sector. Addressing these challenges involves ongoing research into formulating specialized diets, optimizing feeding strategies, and developing alternative and sustainable feed ingredients. To achieve a deeper comprehension of these challenges, studies employing model species have emerged as pivotal tools. These models offer advantages in understanding reproductive mechanisms due to their well-defined physiology, genetic tractability, and ease of manipulation. Yet, while providing invaluable insights, their applicability to diverse species remains constrained by inherent variations across taxa and oversimplification of complex environmental interactions, thus limiting the extrapolation of the scientific findings. Bridging these gaps necessitates multidisciplinary approaches, emphasizing conservation efforts for wild species and tailored nutritional strategies for aquaculture, thereby fostering sustainable teleost reproduction in the Mediterranean.

Toxic mechanism in Daphnia magna due to phthalic acid esters and CuO nanoparticles co-exposure: The insight of physiological, microbiomic and metabolomic profiles

Various phthalic acid esters (PAEs) such as dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP) co-exist with nanopollutants in aquatic environment. In this study, Daphnia magna was exposed to nano-CuO and DBP or BBP at environmental relevant concentrations for 21-days to investigate these combined toxic effects. Acute EC50 values (48 h) of nano-CuO, DBP, and BBP were 12.572 mg/L, 8.978 mg/L, and 4.785 mg/L, respectively. Results showed that co-exposure with nano-CuO (500 μg/L) for 21 days significantly enhanced the toxicity of DBP (100 μg/L) and BBP (100 μg/L) to Daphnia magna by 18.37% and 18.11%, respectively. The activities of superoxide dismutase, catalase, and glutathione S-transferase were enhanced by 10.95% and 14.07%, 25.63% and 25.91%, and 39.93% and 35.01% in nano-CuO+DBP and nano-CuO+BBP treatments as compared to the individual exposure groups, verifying that antioxidative defense responses were activated. Furthermore, the co-exposure of nano-CuO and PAEs decreased the population richness and diversity microbiota, and changed the microbial community composition in Daphnia magna. Metabolomic analysis elucidated that nano-CuO + PAEs exposure induced stronger disturbance on metabolic network and molecular function, including amino acid, nucleotides, and lipid metabolism-related metabolic pathways, as comparison to PAEs single exposure treatments. In summary, the integration of physiological, microflora, and untargeted metabolomics analysis offers a fresh perspective into the potential ecological risk associated with nanopollutants and phthalate pollution in aquatic ecosystems.

Copper oxide nanoparticles impairs oocyte meiosis maturation by inducing mitochondrial dysfunction and oxidative stress

Copper oxides nanoparticles (CuO NPs) are widely used for a variety of industrial and life science applications. In addition to cause neurotoxicity, hepatotoxicity, immunotoxicity, CuO NPs have also been reported to adversely affect the reproductive system in animals; However, little is known about the effects and potential mechanism of CuO NPs exposure on oocyte quality, especially oocyte maturation. In the present study, we reported that CuO NPs exposure impairs the oocyte maturation by disrupting meiotic spindle assembly and chromosome alignment, as well as kinetochore-microtubule attachment. In addition, CuO NPs exposure also affects the acetylation level of α-tubulin in mice oocyte, which hence impairs microtubule dynamics and organization. Besides, CuO NPs exposure would result in the mis-localization of Juno and Ovastacin, which might be one of the critical factors leading to the failure of oocyte maturation. Finally, CuO NPs exposure impairs the mitochondrial distribution and induced high levels of ROS, which led to the accumulation of DNA damage and occurrence of apoptosis. In summary, our results indicated that CuO NPs exposure had potential toxic effects on female fertility and led to the poor oocyte quality in female mice.