Bio-based plastics are marketed as environmentally friendly alternatives to petroleum-based plastics, although they require specific composting conditions for degradation, which leads to their accumulation in the environment and potential risks to aquatic organisms. We hypothesized that the accumulation of bio-based plastics may induce immunotoxic responses in fish. Our research focused on the accumulation and immunotoxicity of 80 nm polylactic acid (PLA) and polystyrene (PS) (0.1–10 mg/L) on early life stage zebrafish (Danio rerio) exposed for 7 days. Compared to PS, there was a higher accumulation of PLA in larvae. Exposure to PLA resulted in a significant increase in neutrophils and macrophages, while immune protein levels such as Complement 3 (C3), Immunoglobulin M (IgM), and C-reactive protein (CRP) were significantly reduced. Furthermore, the mRNA expression of pro-inflammatory cytokines, including tnf-α and il-6, were significantly elevated in PLA treatments. Additionally, PLA-exposed zebrafish were more susceptible to infection by Vibrio parahaemolyticus. Interestingly, at the same concentration, exposures to PS did not induce significant changes in macrophages or immune protein levels, C3 and IgM. This suggests that PLA has a greater immunotoxic response relative to PS. Our research findings contradict the popular belief that bio-based plastics are non-toxic and harmless, which may have potential risk to aquatic organisms.

中文翻译：

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生物基塑料对早期生命阶段斑马鱼 （Danio rerio） 的免疫毒性反应：石油基塑料的安全替代品？


生物基塑料作为石油基塑料的环保替代品销售，尽管它们需要特定的堆肥条件才能降解，这会导致它们在环境中积累并对水生生物构成潜在风险。我们假设生物基塑料的积累可能会诱导鱼类的免疫毒性反应。我们的研究重点是 80 nm 聚乳酸 （PLA） 和聚苯乙烯 （PS） （0.1-10 mg/L） 对暴露 7 天的早期斑马鱼 （Danio rerio） 的积累和免疫毒性。与 PS 相比，PLA 在幼虫中的积累更高。暴露于 PLA 导致中性粒细胞和巨噬细胞显着增加，而补体 3 （C3） 、免疫球蛋白 M （IgM） 和 C 反应蛋白 （CRP） 等免疫蛋白水平显着降低。此外，在 PLA 处理中，促炎细胞因子（包括 tnf-α 和 il-6）的 mRNA 表达显著升高。此外，暴露于 PLA 的斑马鱼更容易受到副溶血性弧菌的感染。有趣的是，在相同浓度下，暴露于 PS 不会诱导巨噬细胞或免疫蛋白水平、C3 和 IgM 的显着变化。这表明 PLA 相对于 PS 具有更大的免疫毒性反应。我们的研究结果与普遍的看法相矛盾，即生物基塑料无毒无害，这可能对水生生物有潜在风险。