CdSe/ZnS量子点对稀有鮈鲫胚胎发育的影响及其氧化应激作用

本研究以稀有鮈鲫(Gobiocypris rarus)为对象,研究了不同浓度CdSe/ZnS量子点(QDs)暴露下,稀有鮈鲫胚胎发育过程中自主运动频率、内心率和体长的变化,以及利用体内超氧化物歧化酶(SOD)和丙二醛(MDA)作为毒性指标,反映CdSe/ZnS QDs暴露对稀有鮈鲫胚胎发育的氧化应激作用.结果显示:CdSe/ZnS QDs对稀有鮈鲫胚胎72 hpf(hours post fertilization)的半致死浓度(LC50)为319.629 nmol·L-1,96 hpf的半致畸浓度(EC50)为203.312 nmol·L-1.CdSe/ZnS QDs暴露不仅影响稀有鮈鲫胚胎死亡率、畸形率、自主运动频率、孵化时间和孵化率,而且使其内心率减缓、体长缩短,导致胚胎卵凝结,心包囊肿,出现脊椎弯曲等多种毒性现象.同时发现,CdSe/ZnS QDs暴露导致稀有鮈鲫体内MDA含量增加以及SOD活力的降低.这表明CdSe/ZnS QDs对稀有鮈鲫胚胎发育具有致畸、致死作用,而氧化应激可能是引起其胚胎致畸、致死的重要机制之一.

Developmental toxicity and oxidative stress of CdSe/ZnS quantum dots to rare minnow (Gobiocypris rarus) embryos

The toxic effects and oxidative stress of CdSe/ZnS QDs on Chinese rare minnow (Gobiocypris rarus) at different developmental stages were investigated in this study. The results showed that the LC₅₀ for rare minnow embryos exposed to CdSe/ZnS QDs after 72 hpf was 319.629 nmol·L^-1 and the EC₅₀ after 96hpf was 203.312 nmol·L^-1. Embryos exposed to CdSe/ZnS QDs showed a significant increase in mortality and malformation rate, while demonstrated significant reduction in hatching rate and delay in hatching time of fry. The spontaneous movement frequency was accelerated, while the heart rate and body length decreased. Thus the exposure to CdSe/ZnS QDs resulted in many toxic effects to the embryos, such as the condensation of embryonic eggs, the formation of pericardial cysts, and curvature of the spine bending. In addition, it was found that the MDA contents in the embryos in CdSe/ZnS QDs groups significantly increased, whereas the SOD activities of the embryos in the mid-high concentration exposure groups significantly decreased. The results suggested that CdSe/ZnS QDs had teratogenic and lethal effects to rare minnow embryos. The oxidative stress was likely to be one of the key mechanisms of their embryonic toxicity.