Since nano-quantum dots (QDs) are increasingly used as fluorescent dyes in biomedical sciences, the possibility of QDs contaminating aquatic environments is generally increasing. There is concern about potential toxicity of QDs. However, their risks in the aquatic environment are not entirely understood. In this study, the freshwater crab Sinopotamon henanense was exposed to cadmium telluride (CdTe) QDs by intraperitoneal injection to detect the reproductive toxicity of QDs (1/32, 1/16 and 1/4 LD50; Crab was exposed for 1, 3, 5, and 7 days). After CdTe QD exposure, no significant effect was detected on the body weight and gonadosomatic index. Additionally, morphological observations showed tissue vacuolation in the testis, and inflammatory cell infiltration in the ovary. The submicroscopic structure showed that exposure to CdTe QDs damaged the organelles and cell structures of the gonads of S. henanense. Among the adverse effects, pathological changes in the nuclear membrane, mitochondria and lysosomes were particularly significant. Antioxidant enzymes responded differently to different doses of QDs. The 0.5-mg/kg dose induced superoxide dismutase activity in the testes. And in the 1-mg/kg and 4-mg/kg dose QD exposure test, the testis responded by activating glutathione peroxidase and inducing reduced glutathione and overconsuming glutathione peroxidase. Respectively, the ovaries responded by overconsuming superoxide dismutase and glutathione peroxidase and reduced glutathione. Thus, we conclude that the gonads of S. henanense were injured by CdTe QD, and male are better indicators of the toxicity of QDs than female crabs according to greater alterations in tissue structure and antioxidant enzyme in the analyses.
Keywords: CdTe QDs; Enzyme activity; Histopathological analysis; Oxidative stress; Sinopotamon henanense.
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