摘要:
碳纳米管的生态安全和健康风险日益受到人们的广泛关注。本文采用典型的海洋底栖生物——太平洋牡蛎(Crassostrea gigas, C. gigas)作为受试生物，研究了单壁碳纳米管(Single-Walled Carbon Nanotubes, SWCNTs)暴露对其造成的毒性效应及牡蛎自身的防御机制，以期为碳纳米管的海洋生态风险评价提供科学依据。在0.1~10 mg·L-1的SWCNTs暴露96 h后，太平洋牡蛎鳃和消化腺中的丙二醛(malondialdehyde, MDA)含量显著增加(P≤0.05)，总超氧化物歧化酶(superoxide dismutase, SOD)和过氧化氢酶(catalase, CAT)活性呈现显著的剂量依赖性升高(P≤0.05)，cat、hsp70、aox及caspase-7等基因的相对表达量显著上调(P≤0.05)。相比于单独暴露，P-gp蛋白抑制剂Tariquidar与SWCNTs的复合暴露显著增加了鳃和消化腺中MDA含量，产生了更严重的氧化损伤。这些结果表明，SWCNTs暴露对太平洋牡蛎的鳃和消化腺造成了一定程度的氧化损伤，而牡蛎体内的抗氧化系统和多外源性物质抗性机制在防御SWCNTs的过程中起到了至关重要的作用。
Abstract:
The ecological and health risks of carbon nanotubes are receiving more attention. In this study, Pacific oyster (Crassostrea gigas), a kind of typical marine benthic organism, was exposed to single-walled carbon nanotubes (SWCNTs) to investigate the toxicity induced by SWCNTs and the defense mechanism of C.gigas. After 96-h exposure to 0.1-10 mg·L-1 SWCNTs, the content of malondialdehyde (MDA) in gills and digestive glands increased significantly (P≤0.05), the activities of total superoxide dismutase (SOD) and catalase (CAT) showed the significant dose-dependent increase (P≤0.05), and the relative expressions of genes, i.e., cat, hsp70, aox and caspase-7, were significantly up-regulated (P≤0.05). The co-exposure of Tariquidar (P-gp protein inhibitor) and SWCNTs induced the significant increase of the MDA content in gills and digestive glands (P≤0.05), indicating that more serious oxidative damage were caused by the mixture. The results revealed that the antioxidant system and Multi-xenobiotic Resistance Mechanism played vital roles in the defense system of Pacific oyster against the SWCNTs exposure.
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