Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand.
Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
J Hazard Mater. 2024 Mar 5;465:133325. doi: 10.1016/j.jhazmat.2023.133325. Epub 2023 Dec 21.
Global warming and nanoplastics (NPs) are critical global issues. Among NPs, one of the most hazardous types of plastics, polystyrene (PS), poses ecotoxicological threats to several freshwater organisms. The degree of toxicity of PS-NPs is strongly influenced by various environmental factors. This study illustrates the combined effects of temperature and PS-NPs on the water flea Daphnia magna. The sensitivity of D. magna to PS-NPs was tested under control (23 °C) and elevated temperatures (28 °C). As a result, increased temperatures influenced the uptake and accumulation of PS-NPs. Co-exposure to both higher temperatures and PS-NPs resulted in a drastic decrease in reproductive performance. The level of oxidative stress was found to have increased in a temperature-dependent manner. Oxidative stress was stimulated by both stressors, leading to increased levels of reactive oxygen species and antioxidant enzyme activity supported by upregulation of antioxidant enzyme-related genes under combined PS-NPs exposure and elevated temperature. In the imbalanced status of intracellular redox, activation of the p38 mitogen-activated protein kinase signaling pathway was induced by exposure to PS-NPs at high temperatures, which supported the decline of the reproductive capacity of D. magna. Therefore, our results suggest that PS-NPs exposure along with an increase in temperature significantly affects physiological processes triggered by damage from oxidative stress, leading to severely inhibited reproduction of D. magna.
全球变暖和纳米塑料（NPs）是两个重大的全球性问题。在 NPs 中，聚苯乙烯（PS）是最危险的塑料之一，对许多淡水生物具有生态毒性威胁。PS-NPs 的毒性程度强烈受各种环境因素影响。本研究说明了温度和 PS-NPs 对水蚤 Daphnia magna 的联合影响。在对照（23°C）和升高的温度（28°C）下测试了 D. magna 对 PS-NPs 的敏感性。结果表明，升高的温度影响了 PS-NPs 的吸收和积累。同时暴露于较高温度和 PS-NPs 会导致繁殖性能急剧下降。发现氧化应激水平呈温度依赖性增加。两种胁迫都刺激了氧化应激，导致活性氧和抗氧化酶活性增加，并在 PS-NPs 暴露和高温下通过上调抗氧化酶相关基因来支持抗氧化酶活性。在细胞内氧化还原失衡的情况下，高温下 PS-NPs 的暴露激活了 p38 丝裂原活化蛋白激酶信号通路，支持了 D. magna 繁殖能力的下降。因此，我们的结果表明，PS-NPs 暴露伴随着温度升高，显著影响了由氧化应激引起的生理过程，从而严重抑制了 D. magna 的繁殖。
