新兴污染物可能是导致全球两栖动物种群减少的因素。最近,科学家们已经注意到微塑料和纳米材料在两栖动物中潜在的生态毒性,然而,它们对胚胎发育阶段的可能影响仍然不存在。因此,本研究分析了环境相关浓度的聚乙烯微塑料(PEMPs;60mg/L)和二氧化钛纳米颗粒(TiO2NPs;10μg/L)的发育毒性,在牛蛙胚胎上分离或组合(混合组),AquaranaCatesbeiana,适应青蛙胚胎致畸试验(FETAX,96h).与FETAX协议结盟,我们还分析了心率和形态测量数据.暴露降低了暴露于TiO2NP的组的存活率和孵化率,在较小程度上,也影响了Mix组。TiO2NP可能与胚胎的孵化酶相互作用,防止孵化,减少他们的生存。在混合组中减少的影响是由于两种毒物的团聚,使NPs对胚胎的可用性降低。PEMPs附着在绒毛膜的凝胶状胶囊上(通过荧光显微镜证实),保护胚胎免受微塑料对孵化率和存活率的最终直接影响。虽然没有心脏毒性作用,也没有形态学改变,PEMPs组孵化胚胎的腹腔水肿明显增加,这表明渗透调节可能受到微塑料附着在胚胎凝胶状胶囊上的影响。这项研究提供了微塑料和纳米颗粒环境混合物对两栖动物的发育毒性的第一个证据,并加强了对其他两栖动物物种进行更多研究的必要性。尤其是新热带地区的标本,可以呈现更大的敏感性。我们的研究还强调了FETAX方案的几个特征,作为评估几种污染物对两栖动物的胚胎毒性的有用工具。
Emerging contaminants can act as contributing factors to the decline of amphibian populations worldwide. Recently, scientists have drawn attention to the potential ecotoxicity of microplastics and nanomaterials in amphibians, however, their possible effects on embryonic developmental stages are still absent. Thus, the present
study analyzed the developmental toxicity of environmentally relevant concentrations of polyethylene microplastics (PE MPs; 60 mg/L) and titanium dioxide nanoparticles (TiO2 NPs; 10 μg/L), isolated or in combination (Mix group) on bullfrog embryos, Aquarana catesbeiana, adapting the Frog Embryo Teratogenesis Assay (FETAX, 96h). Allied to the FETAX protocol, we also analyzed the heart rate and morphometric data. The exposure reduced the survival and hatching rates in groups exposed to TiO2 NPs, and to a lesser extent, also affected the Mix group. TiO2 NPs possibly interacted with the hatching enzymes of the embryos, preventing hatching, and reducing their survival. The reduced effects in the Mix group are due to the agglomeration of both toxicants, making the NPs less available for the embryos. PE MPs got attached to the gelatinous capsule of the chorion (confirmed by fluorescence microscopy), which protected the embryos from eventual direct effects of the microplastics on the hatching and survival rates. Although there were no cardiotoxic effects nor morphometric alterations, there was a significant increase in abdominal edemas in the hatched embryos of the PE MPs group, which indicates that osmoregulation might have been affected by the attachment of the microplastics on the embryos\' gelatinous capsule. This
study presents the first evidence of developmental toxicity of environmental mixtures of microplastics and nanoparticles on amphibians and reinforces the need for more studies with other amphibian species, especially neotropical specimens that could present bigger sensibility. Our
study also highlighted several features of the FETAX protocol as useful tools to evaluate the embryotoxicity of several pollutants on amphibians.