This study analysed the effects of styrene, a main monomer in plastic manufacturing and acknowledged to be amongst the most common plastic leachates, on early embryo development of the Mediterranean mussel. Embryotoxicity tests showed that styrene impaired normal embryo development at concentrations (0.01 μg/L–1 mg/L) encompassing the environmental range. Occurrence of normal D-veligers was significantly reduced up to 40% of the total, and larval size was reduced of about 20%. D-veligers grown in the presence of styrene (0.1 and 10 μg/L) showed significant reduction of total Multixenobiotic resistance (MXR) efflux activity that was not apparently related to transcriptional expression of genes encoding P-glycoprotein (ABCB) and Mrp (ABCC), the two main ABC transporters of embryonal MXR system. Indeed, ABCB transcription was not affected by styrene, while ABCC was up-regulated. At these same concentrations, transcriptional profiles of 15 genes underlying key biological functions in embryo development and potential targets of adverse effects of styrene were analysed. Main transcriptional effects were observed for genes involved in shell biogenesis and lysosomal responses (down-regulation), and in neuroendocrine signaling and immune responses (up-regulation). On the whole, results indicate that styrene may affect mussel early development through dysregulation of gene transcription and suggest the possible conservation of styrene mode of action across bivalve life cycle and between bivalves and humans, as well as through unpredicted impacts on protective systems and on shell biogenesis.

这项研究分析了苯乙烯（它是塑料制造中的主要单体，并且被认为是最常见的塑料浸出液之一）对地中海贻贝早期胚胎发育的影响。胚胎毒性测试表明，在环境范围内的浓度（0.01μg/ L–1 mg / L）下，苯乙烯会损害正常胚胎发育。正常D-veligers的发生显着减少，最多占总数的40％，幼虫大小减少了约20％。在苯乙烯存在下生长的D-veligers（0.1和10μg/ L）显着降低了总的多异生物抗性（MXR）外排活性，这与编码P-糖蛋白（ABCB）和Mrp（ABCC）的基因的转录表达没有明显关系），这是胚胎MXR系统的两个主要ABC转运蛋白。确实，ABCB转录不受苯乙烯影响，而ABCC被上调了。在这些相同的浓度下，分析了胚胎发育中关键生物学功能和苯乙烯不良反应潜在靶点的15个基因的转录概况。对于参与壳生物发生和溶酶体反应（下调）以及神经内分泌信号传导和免疫反应（上调）的基因，观察到了主要的转录作用。总体而言，结果表明，苯乙烯可能通过基因转录失调影响贻贝的早期发育，并表明在双壳动物的整个生命周期中以及在双壳动物和人类之间，以及通过对保护系统和壳的不可预测的影响，苯乙烯的作用方式可能得以保留。生物发生。