纳米塑料和二氧化钛食相暴露对凡纳滨对虾血细胞功能及抗氧化系统的影响

纳米塑料和纳米金属氧化物粒子在不同领域的使用量日益增多,这些纳米材料进入水生系统可能带来的相关环境风险引起了人们的关注。本文通过食相暴露,分析了100 nm纳米聚苯乙烯(PS)和纳米二氧化钛(TiO2)暴露对凡纳滨对虾(Litopenaeus vannamei)的血细胞功能和氧化还原平衡的干扰。实验组对虾分别投喂混有200 mg/kg和2 000 mg/kg纳米PS和纳米TiO2的饲料,试验周期为28天。在暴露第14天和第28天测定其对凡纳滨对虾的血细胞ROS含量变化、细胞吞噬率和凋亡率,以及肝胰腺组织内的总抗氧化酶(T-AOC)活性、超氧化物歧化酶(SOD)活性、谷胱甘肽巯基转移酶(GST)活性、丙二醛(MDA)含量和Na+/K+-ATP酶活性的影响。结果表明,纳米PS和纳米TiO2均导致凡纳滨对虾血细胞凋亡率显著上升,并且导致肝胰腺组织T-AOC、SOD和GST活性不同程度的升高以及Na+/K+-ATP酶活性显著降低。生物标志物指数(IBR)结果显示,纳米TiO2对凡纳滨对虾产生的胁迫压力高于纳米PS。

Effects of nanoplastics and nanosized titanium dioxide on hemocytes function and antioxidant enzyme activities of Litopenaeus vannamei via dietary exposure

The increasing use of nanoplastics and nanometal oxide particles in different fields have aroused concern about the environmental risks associated with these nanomaterials entering the aquatic system. In the present study, through dietary exposure route, the interference of hemocytes function and oxidative balance of the white shrimp Litopenaeus vannamei after exposure to 100 nm nano-PS and nano-TiO2 was analyzed. Shrimps of treatment groups were fed with diets spiked with nanoPS and nano-TiO2 at doses of 200 mg/kg and 2 000 mg/kg respectively for 28 days. The ROS production, phagocytosis and apoptosis rate of hemocytes as well as the enzymatic activities of total antioxidant capacity (T-AOC), superoxidase dismutase (SOD), glutathione-S-transferase (GST), malondialdehyde level (MDA) and Na/K-ATPase in hepatopancreas were measure at Day-14 and Day-28. The results showed that both nano-PS and nano-TiO2 caused a significant increase in the apoptosis rate of hemocytes. Besides, the activities of T-AOC, SOD and GST in hepatopancreas were elevated to varying degrees, while the significant decrease of Na/K-ATPase activity was observed in the treatment groups. In addition, compared with nano-PS,nano-TiO2 caused more serious oxidative damage to shrimps after 28 days of exposure.