Research On The Effects Of Nano-silica On Zebrafish Embryos Development

Nanomaterials are particles with diameter under 100 nm. Nano-silica has many unique and good properties, so it is more widely used in production. In addition, nanosilica can enter the water environment through direct emission, waste emission, routine use and the other various ways, so it is necessary to evaluate the nanomaterials toxicity to aquatic organisms.To illustrate the effects of nano-silica on zebrafish embryos development, zebrafish were used as the model animal and nano-silica was used as the research object in this study. Adding suspended nano-silica to the water to observe the influence of nanosilica on zebrafish embryos morphology development. Using the gene chip technology, real-time quantitative RT-PCR and whole embryo in situ hybridization technique to reveal the molecular mechanism of the effect of nano-silica on zebrafish from the gene expression level. The developmental toxicity of nanomaterials to aquatic organisms was studied, which would provide the evidence for the safe use of nano-silica.Nano-silica can lead to a decrease in the survival rate, 48 hpf heart rate and 24 hpf autonomous movement frequency of zebrafish embryos through morphology and statistical analysis. It can also cause the deformity in 96 hpf zebrafish, such as pericardial sac edema, yolk sac absorption developmental delay and so on.Microarray analysis found that nano-silica can significantly inhibit the expression of zebrafish embryonic somite development related genes col2a1 a, col9a2 and lect1. It can also promote the expression of the gene her12 which can damage somite development. Quantitative RT-PCR found that nano-silica can significantly reduce the expression of liver development related genes prox, wnt2 bb and mypt1 of 48 hpf zebrafish embryos. It can also reduce the expression of cardiovascular development related genes hand2, mef2 a, nkx2.5, atp1a2 a and flk-1. Whole embryo in situ hybridization experiment found that nano-silica can significantly reduce the expression of cardiovascular development related genes amhc and flk-1 of 48 hpf zebrafish embryos. It can also cause the transfer delay of the original heart tube from line to the left which showed the development delay of the heart. In addition, the nano-silica can hinder the hematopoietic function of zebrafish embryos by affecting the development of original red blood cells and myeloid cells.Nano-silica can induce cell apoptosis in zebrafish embryos by raising the expression of apoptosis related genes bax and bid and reducing the expression of anti-apoptosis related genes bcl-2 and mcl-1b. AO staining results showed that apoptosis mainly concentrated in the heart area. Nano-silica can promote the expression of endoplasmic reticulum stress related genes chop, bip, perk and e IF2 a. The endoplasmic reticulum stress response can be induced in zebrafish embryos.From above results, nano-silica can induce endoplasmic reticulum stress, cell apoptosis in zebrafish embryos and influence the cardiovascular, liver and articulate development of zebrafish embryos.