College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, Shandong, China.
School of Public Health, Qingdao University, Qingdao 266021, China.
J Hazard Mater. 2021 Jul 15;414:125537. doi: 10.1016/j.jhazmat.2021.125537. Epub 2021 Feb 25.
Microplastics are ubiquitous in marine environments and may cause unexpected ecological effects. This study adopted a whole life-cycle exposure to illuminate the impact of polystyrene microplastics on life-history strategies of marine medaka (Oryzias melastigma), including the hatching of embryos, growth and reproduction of F generation, and embryonic and larval development of F offspring. Microplastics accumulated on the eggshell and reduced embryonic hatching rate and larval body length and weight. Similarly, 150 days of microplastic exposure decreased body mass and gonadosomatic index of adult fish, but accelerated sexual maturity of female fish, showing a trade-off between growth and reproduction. Microplastic exposure also caused obvious histopathological damages to gonads and decreased egg productions and fertilization rates. Moreover, parental microplastic exposure induced elevated heartbeats, premature hatching, and slow growth in F offspring. Anti-oxidative stress response, sex hormone disruption, and disturbed transcription of steroidogenic genes in the reproductive axis could partially explain the reproduction impairment and transgenerational trade-offs. Furthermore, transcriptome analysis revealed that the steroid hormone biosynthesis and cytochrome P450 pathways in the testes of male fish were significantly affected after 20 μg/L microplastic exposure. These findings suggest that microplastic pollution may be an emerging threat to the sustainability of marine fish population.
微塑料在海洋环境中无处不在，可能会造成意想不到的生态影响。本研究采用全生命周期暴露的方法，研究了聚苯乙烯微塑料对海洋青鳉（Oryzias melastigma）生活史策略的影响，包括胚胎孵化、F 代生长和繁殖，以及 F 代后代的胚胎和幼虫发育。微塑料会在卵壳上积累，降低胚胎孵化率和幼体体长与体重。同样，150 天的微塑料暴露会降低成鱼的体质量和性腺指数，但会加速雌鱼的性成熟，表现出生长和繁殖之间的权衡。微塑料暴露还会对性腺造成明显的组织病理学损伤，并降低产卵量和受精率。此外，亲代微塑料暴露会引起 F 代心跳加快、提前孵化和生长缓慢。抗氧化应激反应、性激素紊乱以及生殖轴中类固醇生成基因的转录失调部分解释了繁殖损伤和跨代权衡。此外，转录组分析表明，暴露于 20μg/L 微塑料后，雄鱼睾丸中的类固醇激素生物合成和细胞色素 P450 途径受到显著影响。这些发现表明，微塑料污染可能是海洋鱼类种群可持续性的一个新威胁。
