The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China.
The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China.
Environ Pollut. 2021 Aug 15;283:117084. doi: 10.1016/j.envpol.2021.117084. Epub 2021 Apr 3.
Benzo[a]pyrene (B[a]P), a representative polycyclic aromatic hydrocarbon (PAH) compound in marine ecosystem, has great potential for chronic toxicity to marine animals. It is becoming increasingly apparent that reproductive system is the major target of B[a]P, but the adverse effects of B[a]P on subcellular fractions in bivalve gonads have not been elucidated. Scallops Chlamys farreri are used as the experimental species since they are sensitive to environmental pollutants. This study was conducted to investigate how B[a]P affected the gonadal subcellular fractions, including plasma membrane, nucleus, mitochondria and microsome in scallops, and whether subcellular damages were related to reproductive toxicity. The results showed that mature gametes' counts were significantly decreased in B[a]P-treated scallops. Three biological macromolecules (viz., DNA, lipids and proteins) in gonadal subcellular fractions obtained by differential centrifugation suffered damages, including DNA damage, lipid peroxidation and protein carbonylation in B[a]P treatment groups. Interestingly, mitochondria and microsome were more vulnerable to lipid peroxidation and protein carbonylation than plasma membrane and nucleus, meanwhile males were more susceptible to DNA damage than females under B[a]P exposure. In addition, histological analysis showed that B[a]P delayed gonadal development in C. farreri. To summarize, our results indicated that B[a]P caused damages to biological macromolecules in gonadal subcellular fractions and then induced damages to gonadal tissues of C. farreri, which further inhibited gonadal development and ultimately leaded to reduction in fertility. This study firstly reports the impacts of PAHs on subcellular fractions in bivalves and their relationship with reproductive toxicity. Moreover, exposure of reproductive scallops to B[a]P leads to defects in reproduction, raising concerns on the possible long-term consequences of PAHs for natural populations of bivalves.
苯并[a]芘（B[a]P）是海洋生态系统中多环芳烃（PAH）的代表性化合物，对海洋动物具有很大的慢性毒性潜力。越来越明显的是，生殖系统是 B[a]P 的主要靶标，但 B[a]P 对双壳类动物性腺亚细胞成分的不良影响尚未阐明。扇贝 Chlamys farreri 被用作实验物种，因为它们对环境污染物敏感。本研究旨在探讨 B[a]P 如何影响扇贝性腺的亚细胞成分，包括质膜、核、线粒体和微粒体，以及亚细胞损伤是否与生殖毒性有关。结果表明，B[a]P 处理的扇贝成熟配子数明显减少。通过差速离心获得的性腺亚细胞成分中的三种生物大分子（即 DNA、脂质和蛋白质）受到损伤，包括 B[a]P 处理组中的 DNA 损伤、脂质过氧化和蛋白质羰基化。有趣的是，与质膜和核相比，线粒体和微粒体更容易受到脂质过氧化和蛋白质羰基化的影响，而在 B[a]P 暴露下，雄性比雌性更容易受到 DNA 损伤。此外，组织学分析表明，B[a]P 延迟了 C. farreri 的性腺发育。总之，我们的结果表明，B[a]P 对性腺亚细胞成分中的生物大分子造成损伤，进而对 C. farreri 的性腺组织造成损伤，从而抑制性腺发育，最终导致生殖力下降。本研究首次报道了多环芳烃对双壳类动物亚细胞成分的影响及其与生殖毒性的关系。此外，生殖扇贝暴露于 B[a]P 会导致生殖缺陷，这引起了人们对多环芳烃对双壳类动物自然种群可能产生的长期影响的关注。
