NANOPARTICLES ACTIVITY DISTURB XENOPUS LAEVIS EMBRYOGENESIS

Nanoparticles (NPs) have extensive industrial, biotechnological, and biomedical/pharmaceutical applications, leading to concerns over health risks to humans and biota. Because of their properties NPs are attractive for basic science also. Size, surface charge, geometry, and its modifications contribute to NPs toxicity. The aquatic environment is at risk of exposure to NPs, as it acts as a sink for environmental contaminants. There are insufficient evidence for environmental concentrations and derived harms for almost all NPs. This finding requires more standardised approaches for NPs hazard identification. The possibility to relate the data obtained in Xenopus laevis with higher vertebrates, including humans, makes it a convincing study model. Our aim is to evaluate the activity of three different commercial NPs: AgNPs, AuNPs and SiO2NPs, 20nm sized, on the embryogenesis of X. laevis. These commercial NPs were used as model to understand the possible consequences of similar NPs utilized in medicine. DLS and TEM was performed to characterize these NPs. The embryos were reared starting from st4/8 in FETAX containing 0.01, 1 and 5 mg/L NPs. All embryos were harvested at st46/47. The mortality, morphology, length, heartbeat and pigment distribution were statistically analyzed. Real Time-PCR were carried out from embryos st.46 to verify gene expression. Our data showed that all NPs, that we tested, aggregate in FETAX and do not cause mortality. Embryos treated with AuNPs are longer and bradycardic compared with control, whereas those treated with AgNPs or SiO2NPs are shorter and tachycardic (AgNPs).The pigment distribution and gene expressions are altered. In conclusion our studies indicate that the NPs that we tested affect embryonic development impairing the expression of genes involved in the early embryogenesis.