CuInS2/ZnS QD exposure induces developmental toxicity, oxidative stress and DNA damage in rare minnow (Gobiocypris rarus) embryos and larvae

Chinese rare minnow (Gobiocypris rarus) embryos were used as an experimental model to investigate the effects of CuInS2/ZnS quantum dots (QDs) on the early life stages of G. rarus. Normal developmental parameters (survival rate, body length and average heart rate), biomarker genes [stress response (Hsp70), detoxification (Cyp1a), organizer function and axis formation (Wnt8α), and muscle (Mstn)], enzymatic activity and DNA damage were recorded as endpoints in the developing embryos/larvae after exposure until 96 h post-fertilization (hpf). Reduced survival rate, decreased heart rate, altered body length, increased malformation rate, decreased hatching rate, advanced hatching time in response to low concentrations (50 and 100 nmol/L) and delayed hatching time in response to high concentrations were observed after exposure, as were many other toxic effects, including pericardial edema and bent tails. The 72 hpf LC50 (median lethal concentration) was determined to be 624.364 nmol/L. Treatment with certain concentrations of CuInS2/ZnS QDs significantly increased the superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels and significantly induced DNA damage. After treatment with CuInS2/ZnS QDs, the embryos showed highly up-regulated expression of Hsp70, Cyp1a and Wnt8a and significantly up-regulated expression of Mstn at 12 hpf. Overall, this study indicates that CuInS2/ZnS QDs are potentially toxic to G. rarus embryos. The information presented in this study will be helpful for fully understanding the toxicity induced by CuInS2/ZnS QDs in fish embryos.